- Home
- Kinesiology/Exercise and Sport Science
- Motor Control and Learning
Motor Control and Learning
A Behavioral Emphasis
by Richard A. Schmidt, Timothy D. Lee, Carolee Winstein, Gabriele Wulf and Howard N. Zelaznik
552 Pages
Motor Control and Learning, Sixth Edition With Web Resource, focuses on observable movement behavior, the many factors that influence quality of movement, and how movement skills are acquired. The text examines the motivational, cognitive, biomechanical, and neurological processes of complex motor behaviors that allow human movement to progress from unrefined and clumsy to masterfully smooth and agile.
This updated sixth edition builds upon the foundational work of Richard Schmidt and Timothy Lee in previous editions. The three new authors—each a distinguished scholar—offer a range and depth of knowledge that includes current directions in the field. The extensively revised content reflects the latest research and new directions in motor control and learning. Additional new features of the sixth edition include the following:
• A web resource that includes narratives and learning activities from Motor Control in Everyday Actions that correspond with the chapters in the book, giving students additional opportunities to analyze how research in motor learning and control can be expanded and applied in everyday settings
• An instructor guide that offers sample answers for the learning experiences found in the student web resource
• New content on sleep and movement memory, the role of vision, illusions and reaching, the OPTIMAL theory of motor learning, the neuroscience of learning, and more
Motor Control and Learning begins with a brief introduction to the field and an introduction to important concepts and research methods. Part II thoroughly covers motor control with topics such as closed-loop perspective, the role of the central nervous system for movement control, speed and accuracy, and coordination. Part III deals with motor learning, exploring the effects of attentional focus, the structure of practice sessions, the role of feedback, theoretical views of motor learning, and the retention and transfer of skills.
Throughout the book, art and practical examples are included to elucidate complex topics. Sidebars with historical examples, classic research, and examples of real-world applications highlight the importance of motor control and learning research and bring attention to influential research studies and pioneers. End-of-chapter summaries and student assignments reinforce important concepts and terms and provide review opportunities. For instructors, an image bank complements the new instructor guide; it is available to course adopters at www.HumanKinetics.com/MotorControlAndLearning.
The updated research, new features, and highly respected authors of Motor Control and Learning, Sixth Edition With Web Study Guide, provide a solid foundation for both students and practitioners who study and work in fields that encompass movement behavior.
Part I. Introduction to Motor Behavior
Chapter 1. Evolution of a Field of Study
Understanding Movement
Origins of the Field
Summary
Chapter 2. Methodology for Studying Motor Performance
Classification of Motor Skills
Basic Considerations in Measurement
Measuring Motor Behavior
Measuring and Evaluating Relationships
Reliability and Individual Differences
Summary
Chapter 3. Human Information Processing
Information-Processing Model
Three Stages of Information Processing
Anticipation
Signal-Detection Theory
Memory
Summary
Chapter 4. Attention and Performance
Types of Attention
Theories of Attention
Competition for Attention
Attention During Movement
Focus of Attention
Automaticity: The Constrained Action Hypothesis
Attention and Anxiety
Summary
Part II. Motor Control
Chapter 5. Sensory and Perceptual Contributions to Motor Control
Closed-Loop Control Systems
Vision
Audition
Proprioceptors
Proprioception and Motor Control
Feedforward Influences on Motor Control
Summary
Chapter 6. Central Contributors to Motor Control
Open-Loop Processes
Central Control Mechanisms
Central Control of Rapid Movements
Generalized Motor Programs
Summary
Chapter 7. Principles of Speed and Accuracy
Fitts’ Law: The Logarithmic Speed–Accuracy Trade-Off
Linear Speed–Accuracy Trade-Off (Schmidt’s Law)
Temporal Speed–Accuracy Trade-Off
Central Contributions to the Spatial Speed–Accuracy Trade-Off
Correction Models of the Speed–Accuracy Trade-Off
Summary
Chapter 8. Coordination
Discrete Tasks
Continuous Tasks
A Dynamical-Systems Account of Coordination
Summary
Part III. Motor Learning
Chapter 9. Motor Learning Concepts and Research Methods
Defining Motor Learning
Measuring Motor Learning
Designing Experiments on Learning
Using Alternative Methods to Measure Learning
Understanding Issues About the “Amount” of Learning
Understanding Learning and Performance Variables
Summary
Chapter 10. Conditions of Practice
Verbal information
Focus of Attention
Motivational Influences on Learning
Observational Learning
Mental Practice
Distribution of Practice
Variability of Practice
Contextual Interference
Guidance
Summary
Chapter 11. Augmented Feedback
Classifications and Definitions
Informational Functions of Feedback
Motivational Functions of Feedback
Attentional Focus Functions of Feedback
Theoretical Issues: How Does Augmented Feedback “Work”?
Summary
Chapter 12. The Learning Process
Stages of Motor Learning
Closed-Loop Theory
Schema Theory
Differing Theoretical Perspectives of Motor Learning
OPTIMAL Theory
Summary
Chapter 13. Retention and Transfer
Fundamental Distinctions and Definitions
Measuring Retention and Transfer
Retention and Motor Memory
Retention Loss
Transfer of Learning
Summary
Richard A. Schmidt, PhD, passed away in 2015, leaving a legacy of groundbreaking research in motor control and learning. He had authored the first edition of Motor Control and Learning in 1982; followed up with a second edition of the popular text in 1988; and collaborated with Timothy Lee for the third edition in 1999, the fourth edition in 2005, and the fifth edition in 2011.
Schmidt was a professor emeritus in the department of psychology at UCLA and ran a consulting firm, Human Performance Research, working in the areas of human factors and human performance. The originator of schema theory, Schmidt founded the Journal of Motor Behavior in 1969 and was editor for 11 years.
Schmidt received two honorary doctorate degrees, from Catholic University of Leuven (Belgium) and Joseph Fournier University (France), in recognition of his work. He was a member of the North American Society for the Psychology of Sport and Physical Activity (of which he was president in 1982), the Human Factors and Ergonomics Society, and the Psychonomic Society.
Timothy D. Lee, PhD, is a professor emeritus in the department of kinesiology at McMaster University in Hamilton, Ontario. He has published extensively in motor behavior and psychology journals since 1979, served as an editor for the Journal of Motor Behavior and Research Quarterly for Exercise and Sport, and has been an editorial board member for Psychological Review. Until his retirement in 2014, his research was supported primarily by grants from the Natural Sciences and Engineering Research Council of Canada.
Lee is a member and past president of the Canadian Society for Psychomotor Learning and Sport Psychology (SCAPPS) and a member of the North American Society for the Psychology of Sport and Physical Activity (NASPSPA). In 1980, Lee received the inaugural Young Scientist Award from SCAPPS, and 31 years later he was awarded its highest honor, being named a fellow of the society. He presented a prestigious senior lecture at NASPSPA’s 2005 conference and received the organization’s highest honor, the Distinguished Scholar Award, in 2017.
In his leisure time, Lee enjoys playing golf. He has maintained a lifelong fascination with blues music and would one day love to put years of motor learning study into practice by learning to play blues guitar.
Carolee J. Winstein, PhD, PT, is a professor of biokinesiology and physical therapy at the University of Southern California, as well as in the department of neurology at the Keck School of Medicine. Winstein serves as an associate editor of the journal Neurorehabilitation and Neural Repair and is a fellow of the American Physical Therapy Association (APTA), the American Heart Association (AHA), and the National Academy of Kinesiology (NAK).
She has more than 30 years of multidisciplinary collaborative research experience focused on understanding rehabilitation outcomes and promoting optimal recovery of goal-directed movement behaviors that emerge from a dynamic brain-behavior system in brain-damaged conditions.
Over the past 25 years, her research program has been consistently funded through NIH, NIDILRR, and the Foundation for Physical Therapy. She has authored or coauthored more than 120 research papers, chapters, proceedings, and commentaries. Recently, the Journal of the American Medicaal Association published the results of her NIH-funded, multisite clinical trial of stroke rehabilitation. Winstein has mentored over a dozen doctoral students and postdoctoral scholars from diverse fields, including engineering, neuroscience, and rehabilitation.
In her free time, Winstein enjoys gourmet cooking and is pursuing her private pilot’s license to fly a Cessna 172.
Gabriele Wulf, PhD, is a professor in the department of kinesiology and nutrition sciences at the University of Nevada at Las Vegas. Wulf studies factors that influence motor skill learning, including the performer’s focus of attention and motivational variables (e.g., autonomy support and performance expectancies). Wulf has received various awards for her research, including UNLV’s Barrick Distinguished Scholar Award. She served as president of the North American Society for the Psychology of Sport and Physical Activity (NASPSPA) in 2015. She has been elected a fellow of the National Academy of Kinesiology (NAK).
Her research has resulted in approximately 200 journal articles and book chapters, as well as two books. She served as the founding editor of Frontiers in Movement Science and Sport Psychology (2010-2012) and the Journal of Motor Learning and Development (2012-2015). In conjunction with Rebecca Lewthwaite, Wulf developed the OPTIMAL theory of motor learning.
In her leisure time, Wulf enjoys golf, tennis, skiing, and photography.
Howard N. Zelaznik, PhD, is a professor of health and kinesiology at Purdue University. He is a fellow of the National Academy of Kinesiology, the Association for Psychological Science, the Psychonomic Society, and the American Association for the Advancement of Science, and he is an active member of the North American Society for the Psychology of Sport and Physical Activity. Zelaznik has served as executive editor for the Journal of Motor Behavior.
His research specialty is human motor control. Over the past 15 years, Zelaznik has developed, tested, and promoted a theoretical framework to examine issues in human movement timing. He has been funded for over 30 years by NIH and currently has an interdisciplinary project funded by NSF.
A former college tennis player, Zelaznik is still an active (albeit unranked) tennis player. He is an active road cyclist and former marathon runner. As his students continually tell him, he does not have a good sense of humor, although he loves to laugh.
“This book provides a blend of current literature and classic studies in motor control and learning, and the authors cite advantages and limitations for the research. I found part III the most thought-provoking and applicable to my practice of physical therapy, particularly chapter 10, which discusses how conditions of practice influence motor learning. The book comprehensively examines human movement and performance.”
—Doody’s Review Service
Using constant error and variable error
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE.
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE. This situation was described years ago by Chapanis (1951) and is illustrated in figure 2.4 (see "The Relative Importance of Constant and Variable Errors"). Which riflemanman, A or B, appears to be the more skilled?
The study of motor learning will show that the measure of error that is most sensitive to the effects of practice is consistency (VE); bias (CE) often changes quickly in the first several trials and remains near zero thereafter, even after years of practice. There are some situations, however, in which CE is preferred to VE; but these are specialized applications. Thus, these two measures of error, CE and VE, seem to represent two distinct aspects of performance - bias and variability, respectively. But sometimes it is more desirable to have a single measure of "overall error" that combines both of these performance indicators rather than using separate measures of accuracy and inconsistency.
The Relative Importance of Constant and Variable Errors
Research Capsule
Alphonse Chapanis was one of the pioneers in the emergence of human factors research. His analysis of errors in movement is as important today as it was over a half century ago.
"Having defined constant and variable errors, we might ask: Which is the more important? Let us return for a moment to the target patterns shot by the two riflemen [figure 2.4]. At first glance, you might say that B is a very inaccurate shooter. And yet any rifleman will tell you that this is not the case at all. B is a much better shooter than A. The reason is this: The large constant error in the trial shots fired by B can be compensated for very easily by simple adjustments in his sights. With suitable corrections in elevation and windage, rifleman B will turn in a perfect score. In rifle shooting, then, constant errors are not the important ones, because they can be very easily adjusted for by changing the position of the sights on the gun. The really important errors are the variable errors. No correction of the sights on A's gun will make all of his shots fall in the center. He is inherently much too variable." (Chapanis, 1951, p. 1187)
Figure 2.4 Distribution of rifle shots. Rifleman A has a small constant error (CE) and large variable error (VE). Rifleman B has a large CE bias, but a small VE.
Reprinted, by permission, from A. Chapanis, 1951, "Theory and methods for analyzing errors in man-machine systems," Annals of the New York Academy of Sciences 51: 1181.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Visual proprioception
Figure 5.4 illustrates one of James Gibson’s concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979).
Figure 5.4 illustrates one of James Gibson's concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979). The pattern of rays experienced is called the optical array, and it provides a unique specification of the location of the eye in space. The changes in the optical array when the eye is moved from one place to another are called the optical flow, implying that the visual environment "flows past us" as we move around. An important point is that the particular patterns of flow specify distinct kinds of movements of the eyes with respect to the environment. For example, if the angle between the light rays from two sides of an object is constant over time, this specifies that you are not moving with respect to that object. If the angle between these rays is increasing, then you are moving toward the object; if it is decreasing, you are moving away from it. Also, if the angles from two sides of an object (with respect to straight ahead) are increasing at the same rate, the eye is moving toward the center of the object (e.g., your eye(s) are moving toward the center of a picture on the wall). In conditions in which the angles from both sides of an object are changing in the same direction, if the rate of increase in the angle of the rays from the right side of the object is greater than the rate of increase from the left side and continues in this way, you will pass the object so that it is on your right side.
Figure 5.4 The detection of distance: The angles of the light rays from the distant pole change less than those from the near pole as the head and eyes are moved.
The optical flow generated as you move in the environment also tells you about the environment itself in ways that could not be achieved if you were stationary. For example, imagine looking out the window at two telephone poles as illustrated in figure 5.4. Which of them is closer? The question is difficult to answer if you remain still, because the poles appear to be nearly the same thickness and height. But if you move your head sideways, you can tell immediately. You will notice that one of the poles seems to "move more quickly" as you change head position. This, of course, is the same as saying that the angles of the rays received from one object changed more quickly (α1 in the figure) than did those from the other (α2), implying that pole 1 is closer than pole 2. Thus, the visual system, through movement of the entire head, body, or both, can provide rich information about the nature of the environment. In this view, vision is not merely an exteroceptive sense, passively providing information about the environment. It is also a proprioceptive sense telling us about our own movements. As well, vision is dependent on movement in some situations for informing us about the environment. In this way, vision and movement are very closely and reciprocally linked. Excellent discussions of this basic idea are found in Gibson (1966, 1979) and Lee (1980; Lee & Young, 1985), the latter showing relevance to many situations, such as sport-related motions and bird flight.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Fundamental distinctions and definitions in motor learning
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill.
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill. This is because psychologists and others tend to use the metaphor of memory as a place where information is stored, such as a computer hard drive or a library. Statements like "I have a good memory for names and dates," or "The person placed the phone number in long-term memory," are representative of this use of the term. The implication is that some set of processes has led to the acquisition of the materials, and now some other set of processes is responsible for keeping them "in" memory.
Memory
A common meaning of the term motor memory is "the persistence of the acquired capability for performance." In this sense, habit and memory are conceptually similar. Remember, the usual test for learning of a task concerns how well the individual can perform the skill on a retention or transfer test. That is, a skill has been learned if and only if it can be retained "relatively permanently" (see chapter 9). If you can still perform a skill after not having practiced it for a year (or even for a day or just a few minutes), then you have a memory of the skill. In this sense, memory is the capability for performance, not a location where that capability is stored. Depending on one's theoretical orientation about motor learning, memory could be a motor program, a reference of correctness, a schema, or an intrinsic coordination pattern (Amazeen, 2002). From this viewpoint, as you can see, learning and memory are just "different sides of the same behavioral coin," as Adams (1976a, p. 223) put it (see also Adams, 1967).
Chapter 9 introduced the motor behavior - memory framework that connects the temporal evolution of motor memory processes and the phases of motor learning (Kantak & Winstein, 2012). Memory researchers describe the information processes as encoding, consolidation, and retrieval. Because learning and memory are just different sides of the same behavioral coin, we can map motor learning processes onto memory processes using this framework. Thus, acquisition or practice corresponds to the encoding processes of a motor memory, and the end-of-practice or immediate retention phase of motor learning corresponds to consolidation processes where the memory is somewhat more fragile, and finally, the delayed retention or transfer phase that represents retrieval processes are referred to as recall. We refer back to these memory processes throughout this chapter as they relate to retention and transfer.
Forgetting
Another term used in this context is forgetting. The term is used to indicate the opposite of learning, in that learning refers to the acquisition of the capability for movement whereas forgetting refers to the loss of such capability. It is likely that the processes and principles having to do with gains and losses in the capability for moving will be different, but the terms refer to the different directions of the change in this capability. "Forgetting" is a term that has to do with theoretical constructs, just as "learning" does. Memory is a construct, and forgetting is the loss of memory; so forgetting is a concept at a theoretical, rather than a behavioral, level of thinking.
As shown in table 13.1, the analogy to the study of learning is a close one. At the theoretical level, learning is a gain in the capability for skilled action, while forgetting is the loss of same. On the behavioral level, learning is evidenced by relatively permanent gains in performance, while forgetting is evidenced by relatively permanent losses in performance, or losses in retention. So, if you understand what measures of behavior suggest about learning, then you also understand the same about forgetting. Remember that we cannot measure forgetting directly; like learning, it must be inferred from performance. As such, an inability to retrieve a specific memory may only reflect a problem with the retrieval mechanism and not the memory itself. A good example of this phenomenon is behavior after head trauma when a loss of memory is evidenced by forgetting. With time, however, the person is usually able to retrieve the information and thereby demonstrate that memory was intact all along but the retrieval processes were temporarily impaired (Coste et al., 2011).
Retention and Transfer
Retention refers to the persistence or lack of persistence of the performance, and is considered at the behavioral level rather than at the theoretical level (table 13.1). It might or might not tell us whether memory has been lost. The test on which decisions about retention are based is called the retention test, performed at a period of time after practice trials have ended (following the retention interval). If performance on the retention test is as proficient as it was immediately after the end of the practice session (or acquisition phase), then we might be inclined to say that no memory loss (no forgetting) has occurred. If performance on the retention test is poor, then we may decide that a memory loss has occurred. However, because the test for memory (the retention test) is a test of performance, it is subject to all the variations that cause performances to change in temporary ways - just as in the study of learning. Thus, it could be that performance is poor on the retention test for some temporary reason (fatigue, anxiety) or a problem with the retrieval processes mentioned earlier, and so one could falsely conclude that a memory loss has occurred. (At this point it might be helpful to review the learning - performance distinction presented in chapter 9.)
For all practical purposes, a retention test and a transfer test are very similar. In both cases, the interest is in the persistence of the acquired capability for performance (habit). The two types of tests differ only in that the transfer test has individuals (all or some) switching to different tasks or conditions, whereas the retention test usually involves retesting people on the same task or conditions.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Using constant error and variable error
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE.
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE. This situation was described years ago by Chapanis (1951) and is illustrated in figure 2.4 (see "The Relative Importance of Constant and Variable Errors"). Which riflemanman, A or B, appears to be the more skilled?
The study of motor learning will show that the measure of error that is most sensitive to the effects of practice is consistency (VE); bias (CE) often changes quickly in the first several trials and remains near zero thereafter, even after years of practice. There are some situations, however, in which CE is preferred to VE; but these are specialized applications. Thus, these two measures of error, CE and VE, seem to represent two distinct aspects of performance - bias and variability, respectively. But sometimes it is more desirable to have a single measure of "overall error" that combines both of these performance indicators rather than using separate measures of accuracy and inconsistency.
The Relative Importance of Constant and Variable Errors
Research Capsule
Alphonse Chapanis was one of the pioneers in the emergence of human factors research. His analysis of errors in movement is as important today as it was over a half century ago.
"Having defined constant and variable errors, we might ask: Which is the more important? Let us return for a moment to the target patterns shot by the two riflemen [figure 2.4]. At first glance, you might say that B is a very inaccurate shooter. And yet any rifleman will tell you that this is not the case at all. B is a much better shooter than A. The reason is this: The large constant error in the trial shots fired by B can be compensated for very easily by simple adjustments in his sights. With suitable corrections in elevation and windage, rifleman B will turn in a perfect score. In rifle shooting, then, constant errors are not the important ones, because they can be very easily adjusted for by changing the position of the sights on the gun. The really important errors are the variable errors. No correction of the sights on A's gun will make all of his shots fall in the center. He is inherently much too variable." (Chapanis, 1951, p. 1187)
Figure 2.4 Distribution of rifle shots. Rifleman A has a small constant error (CE) and large variable error (VE). Rifleman B has a large CE bias, but a small VE.
Reprinted, by permission, from A. Chapanis, 1951, "Theory and methods for analyzing errors in man-machine systems," Annals of the New York Academy of Sciences 51: 1181.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Visual proprioception
Figure 5.4 illustrates one of James Gibson’s concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979).
Figure 5.4 illustrates one of James Gibson's concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979). The pattern of rays experienced is called the optical array, and it provides a unique specification of the location of the eye in space. The changes in the optical array when the eye is moved from one place to another are called the optical flow, implying that the visual environment "flows past us" as we move around. An important point is that the particular patterns of flow specify distinct kinds of movements of the eyes with respect to the environment. For example, if the angle between the light rays from two sides of an object is constant over time, this specifies that you are not moving with respect to that object. If the angle between these rays is increasing, then you are moving toward the object; if it is decreasing, you are moving away from it. Also, if the angles from two sides of an object (with respect to straight ahead) are increasing at the same rate, the eye is moving toward the center of the object (e.g., your eye(s) are moving toward the center of a picture on the wall). In conditions in which the angles from both sides of an object are changing in the same direction, if the rate of increase in the angle of the rays from the right side of the object is greater than the rate of increase from the left side and continues in this way, you will pass the object so that it is on your right side.
Figure 5.4 The detection of distance: The angles of the light rays from the distant pole change less than those from the near pole as the head and eyes are moved.
The optical flow generated as you move in the environment also tells you about the environment itself in ways that could not be achieved if you were stationary. For example, imagine looking out the window at two telephone poles as illustrated in figure 5.4. Which of them is closer? The question is difficult to answer if you remain still, because the poles appear to be nearly the same thickness and height. But if you move your head sideways, you can tell immediately. You will notice that one of the poles seems to "move more quickly" as you change head position. This, of course, is the same as saying that the angles of the rays received from one object changed more quickly (α1 in the figure) than did those from the other (α2), implying that pole 1 is closer than pole 2. Thus, the visual system, through movement of the entire head, body, or both, can provide rich information about the nature of the environment. In this view, vision is not merely an exteroceptive sense, passively providing information about the environment. It is also a proprioceptive sense telling us about our own movements. As well, vision is dependent on movement in some situations for informing us about the environment. In this way, vision and movement are very closely and reciprocally linked. Excellent discussions of this basic idea are found in Gibson (1966, 1979) and Lee (1980; Lee & Young, 1985), the latter showing relevance to many situations, such as sport-related motions and bird flight.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Fundamental distinctions and definitions in motor learning
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill.
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill. This is because psychologists and others tend to use the metaphor of memory as a place where information is stored, such as a computer hard drive or a library. Statements like "I have a good memory for names and dates," or "The person placed the phone number in long-term memory," are representative of this use of the term. The implication is that some set of processes has led to the acquisition of the materials, and now some other set of processes is responsible for keeping them "in" memory.
Memory
A common meaning of the term motor memory is "the persistence of the acquired capability for performance." In this sense, habit and memory are conceptually similar. Remember, the usual test for learning of a task concerns how well the individual can perform the skill on a retention or transfer test. That is, a skill has been learned if and only if it can be retained "relatively permanently" (see chapter 9). If you can still perform a skill after not having practiced it for a year (or even for a day or just a few minutes), then you have a memory of the skill. In this sense, memory is the capability for performance, not a location where that capability is stored. Depending on one's theoretical orientation about motor learning, memory could be a motor program, a reference of correctness, a schema, or an intrinsic coordination pattern (Amazeen, 2002). From this viewpoint, as you can see, learning and memory are just "different sides of the same behavioral coin," as Adams (1976a, p. 223) put it (see also Adams, 1967).
Chapter 9 introduced the motor behavior - memory framework that connects the temporal evolution of motor memory processes and the phases of motor learning (Kantak & Winstein, 2012). Memory researchers describe the information processes as encoding, consolidation, and retrieval. Because learning and memory are just different sides of the same behavioral coin, we can map motor learning processes onto memory processes using this framework. Thus, acquisition or practice corresponds to the encoding processes of a motor memory, and the end-of-practice or immediate retention phase of motor learning corresponds to consolidation processes where the memory is somewhat more fragile, and finally, the delayed retention or transfer phase that represents retrieval processes are referred to as recall. We refer back to these memory processes throughout this chapter as they relate to retention and transfer.
Forgetting
Another term used in this context is forgetting. The term is used to indicate the opposite of learning, in that learning refers to the acquisition of the capability for movement whereas forgetting refers to the loss of such capability. It is likely that the processes and principles having to do with gains and losses in the capability for moving will be different, but the terms refer to the different directions of the change in this capability. "Forgetting" is a term that has to do with theoretical constructs, just as "learning" does. Memory is a construct, and forgetting is the loss of memory; so forgetting is a concept at a theoretical, rather than a behavioral, level of thinking.
As shown in table 13.1, the analogy to the study of learning is a close one. At the theoretical level, learning is a gain in the capability for skilled action, while forgetting is the loss of same. On the behavioral level, learning is evidenced by relatively permanent gains in performance, while forgetting is evidenced by relatively permanent losses in performance, or losses in retention. So, if you understand what measures of behavior suggest about learning, then you also understand the same about forgetting. Remember that we cannot measure forgetting directly; like learning, it must be inferred from performance. As such, an inability to retrieve a specific memory may only reflect a problem with the retrieval mechanism and not the memory itself. A good example of this phenomenon is behavior after head trauma when a loss of memory is evidenced by forgetting. With time, however, the person is usually able to retrieve the information and thereby demonstrate that memory was intact all along but the retrieval processes were temporarily impaired (Coste et al., 2011).
Retention and Transfer
Retention refers to the persistence or lack of persistence of the performance, and is considered at the behavioral level rather than at the theoretical level (table 13.1). It might or might not tell us whether memory has been lost. The test on which decisions about retention are based is called the retention test, performed at a period of time after practice trials have ended (following the retention interval). If performance on the retention test is as proficient as it was immediately after the end of the practice session (or acquisition phase), then we might be inclined to say that no memory loss (no forgetting) has occurred. If performance on the retention test is poor, then we may decide that a memory loss has occurred. However, because the test for memory (the retention test) is a test of performance, it is subject to all the variations that cause performances to change in temporary ways - just as in the study of learning. Thus, it could be that performance is poor on the retention test for some temporary reason (fatigue, anxiety) or a problem with the retrieval processes mentioned earlier, and so one could falsely conclude that a memory loss has occurred. (At this point it might be helpful to review the learning - performance distinction presented in chapter 9.)
For all practical purposes, a retention test and a transfer test are very similar. In both cases, the interest is in the persistence of the acquired capability for performance (habit). The two types of tests differ only in that the transfer test has individuals (all or some) switching to different tasks or conditions, whereas the retention test usually involves retesting people on the same task or conditions.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Using constant error and variable error
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE.
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE. This situation was described years ago by Chapanis (1951) and is illustrated in figure 2.4 (see "The Relative Importance of Constant and Variable Errors"). Which riflemanman, A or B, appears to be the more skilled?
The study of motor learning will show that the measure of error that is most sensitive to the effects of practice is consistency (VE); bias (CE) often changes quickly in the first several trials and remains near zero thereafter, even after years of practice. There are some situations, however, in which CE is preferred to VE; but these are specialized applications. Thus, these two measures of error, CE and VE, seem to represent two distinct aspects of performance - bias and variability, respectively. But sometimes it is more desirable to have a single measure of "overall error" that combines both of these performance indicators rather than using separate measures of accuracy and inconsistency.
The Relative Importance of Constant and Variable Errors
Research Capsule
Alphonse Chapanis was one of the pioneers in the emergence of human factors research. His analysis of errors in movement is as important today as it was over a half century ago.
"Having defined constant and variable errors, we might ask: Which is the more important? Let us return for a moment to the target patterns shot by the two riflemen [figure 2.4]. At first glance, you might say that B is a very inaccurate shooter. And yet any rifleman will tell you that this is not the case at all. B is a much better shooter than A. The reason is this: The large constant error in the trial shots fired by B can be compensated for very easily by simple adjustments in his sights. With suitable corrections in elevation and windage, rifleman B will turn in a perfect score. In rifle shooting, then, constant errors are not the important ones, because they can be very easily adjusted for by changing the position of the sights on the gun. The really important errors are the variable errors. No correction of the sights on A's gun will make all of his shots fall in the center. He is inherently much too variable." (Chapanis, 1951, p. 1187)
Figure 2.4 Distribution of rifle shots. Rifleman A has a small constant error (CE) and large variable error (VE). Rifleman B has a large CE bias, but a small VE.
Reprinted, by permission, from A. Chapanis, 1951, "Theory and methods for analyzing errors in man-machine systems," Annals of the New York Academy of Sciences 51: 1181.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Visual proprioception
Figure 5.4 illustrates one of James Gibson’s concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979).
Figure 5.4 illustrates one of James Gibson's concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979). The pattern of rays experienced is called the optical array, and it provides a unique specification of the location of the eye in space. The changes in the optical array when the eye is moved from one place to another are called the optical flow, implying that the visual environment "flows past us" as we move around. An important point is that the particular patterns of flow specify distinct kinds of movements of the eyes with respect to the environment. For example, if the angle between the light rays from two sides of an object is constant over time, this specifies that you are not moving with respect to that object. If the angle between these rays is increasing, then you are moving toward the object; if it is decreasing, you are moving away from it. Also, if the angles from two sides of an object (with respect to straight ahead) are increasing at the same rate, the eye is moving toward the center of the object (e.g., your eye(s) are moving toward the center of a picture on the wall). In conditions in which the angles from both sides of an object are changing in the same direction, if the rate of increase in the angle of the rays from the right side of the object is greater than the rate of increase from the left side and continues in this way, you will pass the object so that it is on your right side.
Figure 5.4 The detection of distance: The angles of the light rays from the distant pole change less than those from the near pole as the head and eyes are moved.
The optical flow generated as you move in the environment also tells you about the environment itself in ways that could not be achieved if you were stationary. For example, imagine looking out the window at two telephone poles as illustrated in figure 5.4. Which of them is closer? The question is difficult to answer if you remain still, because the poles appear to be nearly the same thickness and height. But if you move your head sideways, you can tell immediately. You will notice that one of the poles seems to "move more quickly" as you change head position. This, of course, is the same as saying that the angles of the rays received from one object changed more quickly (α1 in the figure) than did those from the other (α2), implying that pole 1 is closer than pole 2. Thus, the visual system, through movement of the entire head, body, or both, can provide rich information about the nature of the environment. In this view, vision is not merely an exteroceptive sense, passively providing information about the environment. It is also a proprioceptive sense telling us about our own movements. As well, vision is dependent on movement in some situations for informing us about the environment. In this way, vision and movement are very closely and reciprocally linked. Excellent discussions of this basic idea are found in Gibson (1966, 1979) and Lee (1980; Lee & Young, 1985), the latter showing relevance to many situations, such as sport-related motions and bird flight.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Fundamental distinctions and definitions in motor learning
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill.
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill. This is because psychologists and others tend to use the metaphor of memory as a place where information is stored, such as a computer hard drive or a library. Statements like "I have a good memory for names and dates," or "The person placed the phone number in long-term memory," are representative of this use of the term. The implication is that some set of processes has led to the acquisition of the materials, and now some other set of processes is responsible for keeping them "in" memory.
Memory
A common meaning of the term motor memory is "the persistence of the acquired capability for performance." In this sense, habit and memory are conceptually similar. Remember, the usual test for learning of a task concerns how well the individual can perform the skill on a retention or transfer test. That is, a skill has been learned if and only if it can be retained "relatively permanently" (see chapter 9). If you can still perform a skill after not having practiced it for a year (or even for a day or just a few minutes), then you have a memory of the skill. In this sense, memory is the capability for performance, not a location where that capability is stored. Depending on one's theoretical orientation about motor learning, memory could be a motor program, a reference of correctness, a schema, or an intrinsic coordination pattern (Amazeen, 2002). From this viewpoint, as you can see, learning and memory are just "different sides of the same behavioral coin," as Adams (1976a, p. 223) put it (see also Adams, 1967).
Chapter 9 introduced the motor behavior - memory framework that connects the temporal evolution of motor memory processes and the phases of motor learning (Kantak & Winstein, 2012). Memory researchers describe the information processes as encoding, consolidation, and retrieval. Because learning and memory are just different sides of the same behavioral coin, we can map motor learning processes onto memory processes using this framework. Thus, acquisition or practice corresponds to the encoding processes of a motor memory, and the end-of-practice or immediate retention phase of motor learning corresponds to consolidation processes where the memory is somewhat more fragile, and finally, the delayed retention or transfer phase that represents retrieval processes are referred to as recall. We refer back to these memory processes throughout this chapter as they relate to retention and transfer.
Forgetting
Another term used in this context is forgetting. The term is used to indicate the opposite of learning, in that learning refers to the acquisition of the capability for movement whereas forgetting refers to the loss of such capability. It is likely that the processes and principles having to do with gains and losses in the capability for moving will be different, but the terms refer to the different directions of the change in this capability. "Forgetting" is a term that has to do with theoretical constructs, just as "learning" does. Memory is a construct, and forgetting is the loss of memory; so forgetting is a concept at a theoretical, rather than a behavioral, level of thinking.
As shown in table 13.1, the analogy to the study of learning is a close one. At the theoretical level, learning is a gain in the capability for skilled action, while forgetting is the loss of same. On the behavioral level, learning is evidenced by relatively permanent gains in performance, while forgetting is evidenced by relatively permanent losses in performance, or losses in retention. So, if you understand what measures of behavior suggest about learning, then you also understand the same about forgetting. Remember that we cannot measure forgetting directly; like learning, it must be inferred from performance. As such, an inability to retrieve a specific memory may only reflect a problem with the retrieval mechanism and not the memory itself. A good example of this phenomenon is behavior after head trauma when a loss of memory is evidenced by forgetting. With time, however, the person is usually able to retrieve the information and thereby demonstrate that memory was intact all along but the retrieval processes were temporarily impaired (Coste et al., 2011).
Retention and Transfer
Retention refers to the persistence or lack of persistence of the performance, and is considered at the behavioral level rather than at the theoretical level (table 13.1). It might or might not tell us whether memory has been lost. The test on which decisions about retention are based is called the retention test, performed at a period of time after practice trials have ended (following the retention interval). If performance on the retention test is as proficient as it was immediately after the end of the practice session (or acquisition phase), then we might be inclined to say that no memory loss (no forgetting) has occurred. If performance on the retention test is poor, then we may decide that a memory loss has occurred. However, because the test for memory (the retention test) is a test of performance, it is subject to all the variations that cause performances to change in temporary ways - just as in the study of learning. Thus, it could be that performance is poor on the retention test for some temporary reason (fatigue, anxiety) or a problem with the retrieval processes mentioned earlier, and so one could falsely conclude that a memory loss has occurred. (At this point it might be helpful to review the learning - performance distinction presented in chapter 9.)
For all practical purposes, a retention test and a transfer test are very similar. In both cases, the interest is in the persistence of the acquired capability for performance (habit). The two types of tests differ only in that the transfer test has individuals (all or some) switching to different tasks or conditions, whereas the retention test usually involves retesting people on the same task or conditions.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Using constant error and variable error
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE.
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE. This situation was described years ago by Chapanis (1951) and is illustrated in figure 2.4 (see "The Relative Importance of Constant and Variable Errors"). Which riflemanman, A or B, appears to be the more skilled?
The study of motor learning will show that the measure of error that is most sensitive to the effects of practice is consistency (VE); bias (CE) often changes quickly in the first several trials and remains near zero thereafter, even after years of practice. There are some situations, however, in which CE is preferred to VE; but these are specialized applications. Thus, these two measures of error, CE and VE, seem to represent two distinct aspects of performance - bias and variability, respectively. But sometimes it is more desirable to have a single measure of "overall error" that combines both of these performance indicators rather than using separate measures of accuracy and inconsistency.
The Relative Importance of Constant and Variable Errors
Research Capsule
Alphonse Chapanis was one of the pioneers in the emergence of human factors research. His analysis of errors in movement is as important today as it was over a half century ago.
"Having defined constant and variable errors, we might ask: Which is the more important? Let us return for a moment to the target patterns shot by the two riflemen [figure 2.4]. At first glance, you might say that B is a very inaccurate shooter. And yet any rifleman will tell you that this is not the case at all. B is a much better shooter than A. The reason is this: The large constant error in the trial shots fired by B can be compensated for very easily by simple adjustments in his sights. With suitable corrections in elevation and windage, rifleman B will turn in a perfect score. In rifle shooting, then, constant errors are not the important ones, because they can be very easily adjusted for by changing the position of the sights on the gun. The really important errors are the variable errors. No correction of the sights on A's gun will make all of his shots fall in the center. He is inherently much too variable." (Chapanis, 1951, p. 1187)
Figure 2.4 Distribution of rifle shots. Rifleman A has a small constant error (CE) and large variable error (VE). Rifleman B has a large CE bias, but a small VE.
Reprinted, by permission, from A. Chapanis, 1951, "Theory and methods for analyzing errors in man-machine systems," Annals of the New York Academy of Sciences 51: 1181.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Visual proprioception
Figure 5.4 illustrates one of James Gibson’s concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979).
Figure 5.4 illustrates one of James Gibson's concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979). The pattern of rays experienced is called the optical array, and it provides a unique specification of the location of the eye in space. The changes in the optical array when the eye is moved from one place to another are called the optical flow, implying that the visual environment "flows past us" as we move around. An important point is that the particular patterns of flow specify distinct kinds of movements of the eyes with respect to the environment. For example, if the angle between the light rays from two sides of an object is constant over time, this specifies that you are not moving with respect to that object. If the angle between these rays is increasing, then you are moving toward the object; if it is decreasing, you are moving away from it. Also, if the angles from two sides of an object (with respect to straight ahead) are increasing at the same rate, the eye is moving toward the center of the object (e.g., your eye(s) are moving toward the center of a picture on the wall). In conditions in which the angles from both sides of an object are changing in the same direction, if the rate of increase in the angle of the rays from the right side of the object is greater than the rate of increase from the left side and continues in this way, you will pass the object so that it is on your right side.
Figure 5.4 The detection of distance: The angles of the light rays from the distant pole change less than those from the near pole as the head and eyes are moved.
The optical flow generated as you move in the environment also tells you about the environment itself in ways that could not be achieved if you were stationary. For example, imagine looking out the window at two telephone poles as illustrated in figure 5.4. Which of them is closer? The question is difficult to answer if you remain still, because the poles appear to be nearly the same thickness and height. But if you move your head sideways, you can tell immediately. You will notice that one of the poles seems to "move more quickly" as you change head position. This, of course, is the same as saying that the angles of the rays received from one object changed more quickly (α1 in the figure) than did those from the other (α2), implying that pole 1 is closer than pole 2. Thus, the visual system, through movement of the entire head, body, or both, can provide rich information about the nature of the environment. In this view, vision is not merely an exteroceptive sense, passively providing information about the environment. It is also a proprioceptive sense telling us about our own movements. As well, vision is dependent on movement in some situations for informing us about the environment. In this way, vision and movement are very closely and reciprocally linked. Excellent discussions of this basic idea are found in Gibson (1966, 1979) and Lee (1980; Lee & Young, 1985), the latter showing relevance to many situations, such as sport-related motions and bird flight.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Fundamental distinctions and definitions in motor learning
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill.
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill. This is because psychologists and others tend to use the metaphor of memory as a place where information is stored, such as a computer hard drive or a library. Statements like "I have a good memory for names and dates," or "The person placed the phone number in long-term memory," are representative of this use of the term. The implication is that some set of processes has led to the acquisition of the materials, and now some other set of processes is responsible for keeping them "in" memory.
Memory
A common meaning of the term motor memory is "the persistence of the acquired capability for performance." In this sense, habit and memory are conceptually similar. Remember, the usual test for learning of a task concerns how well the individual can perform the skill on a retention or transfer test. That is, a skill has been learned if and only if it can be retained "relatively permanently" (see chapter 9). If you can still perform a skill after not having practiced it for a year (or even for a day or just a few minutes), then you have a memory of the skill. In this sense, memory is the capability for performance, not a location where that capability is stored. Depending on one's theoretical orientation about motor learning, memory could be a motor program, a reference of correctness, a schema, or an intrinsic coordination pattern (Amazeen, 2002). From this viewpoint, as you can see, learning and memory are just "different sides of the same behavioral coin," as Adams (1976a, p. 223) put it (see also Adams, 1967).
Chapter 9 introduced the motor behavior - memory framework that connects the temporal evolution of motor memory processes and the phases of motor learning (Kantak & Winstein, 2012). Memory researchers describe the information processes as encoding, consolidation, and retrieval. Because learning and memory are just different sides of the same behavioral coin, we can map motor learning processes onto memory processes using this framework. Thus, acquisition or practice corresponds to the encoding processes of a motor memory, and the end-of-practice or immediate retention phase of motor learning corresponds to consolidation processes where the memory is somewhat more fragile, and finally, the delayed retention or transfer phase that represents retrieval processes are referred to as recall. We refer back to these memory processes throughout this chapter as they relate to retention and transfer.
Forgetting
Another term used in this context is forgetting. The term is used to indicate the opposite of learning, in that learning refers to the acquisition of the capability for movement whereas forgetting refers to the loss of such capability. It is likely that the processes and principles having to do with gains and losses in the capability for moving will be different, but the terms refer to the different directions of the change in this capability. "Forgetting" is a term that has to do with theoretical constructs, just as "learning" does. Memory is a construct, and forgetting is the loss of memory; so forgetting is a concept at a theoretical, rather than a behavioral, level of thinking.
As shown in table 13.1, the analogy to the study of learning is a close one. At the theoretical level, learning is a gain in the capability for skilled action, while forgetting is the loss of same. On the behavioral level, learning is evidenced by relatively permanent gains in performance, while forgetting is evidenced by relatively permanent losses in performance, or losses in retention. So, if you understand what measures of behavior suggest about learning, then you also understand the same about forgetting. Remember that we cannot measure forgetting directly; like learning, it must be inferred from performance. As such, an inability to retrieve a specific memory may only reflect a problem with the retrieval mechanism and not the memory itself. A good example of this phenomenon is behavior after head trauma when a loss of memory is evidenced by forgetting. With time, however, the person is usually able to retrieve the information and thereby demonstrate that memory was intact all along but the retrieval processes were temporarily impaired (Coste et al., 2011).
Retention and Transfer
Retention refers to the persistence or lack of persistence of the performance, and is considered at the behavioral level rather than at the theoretical level (table 13.1). It might or might not tell us whether memory has been lost. The test on which decisions about retention are based is called the retention test, performed at a period of time after practice trials have ended (following the retention interval). If performance on the retention test is as proficient as it was immediately after the end of the practice session (or acquisition phase), then we might be inclined to say that no memory loss (no forgetting) has occurred. If performance on the retention test is poor, then we may decide that a memory loss has occurred. However, because the test for memory (the retention test) is a test of performance, it is subject to all the variations that cause performances to change in temporary ways - just as in the study of learning. Thus, it could be that performance is poor on the retention test for some temporary reason (fatigue, anxiety) or a problem with the retrieval processes mentioned earlier, and so one could falsely conclude that a memory loss has occurred. (At this point it might be helpful to review the learning - performance distinction presented in chapter 9.)
For all practical purposes, a retention test and a transfer test are very similar. In both cases, the interest is in the persistence of the acquired capability for performance (habit). The two types of tests differ only in that the transfer test has individuals (all or some) switching to different tasks or conditions, whereas the retention test usually involves retesting people on the same task or conditions.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Using constant error and variable error
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE.
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE. This situation was described years ago by Chapanis (1951) and is illustrated in figure 2.4 (see "The Relative Importance of Constant and Variable Errors"). Which riflemanman, A or B, appears to be the more skilled?
The study of motor learning will show that the measure of error that is most sensitive to the effects of practice is consistency (VE); bias (CE) often changes quickly in the first several trials and remains near zero thereafter, even after years of practice. There are some situations, however, in which CE is preferred to VE; but these are specialized applications. Thus, these two measures of error, CE and VE, seem to represent two distinct aspects of performance - bias and variability, respectively. But sometimes it is more desirable to have a single measure of "overall error" that combines both of these performance indicators rather than using separate measures of accuracy and inconsistency.
The Relative Importance of Constant and Variable Errors
Research Capsule
Alphonse Chapanis was one of the pioneers in the emergence of human factors research. His analysis of errors in movement is as important today as it was over a half century ago.
"Having defined constant and variable errors, we might ask: Which is the more important? Let us return for a moment to the target patterns shot by the two riflemen [figure 2.4]. At first glance, you might say that B is a very inaccurate shooter. And yet any rifleman will tell you that this is not the case at all. B is a much better shooter than A. The reason is this: The large constant error in the trial shots fired by B can be compensated for very easily by simple adjustments in his sights. With suitable corrections in elevation and windage, rifleman B will turn in a perfect score. In rifle shooting, then, constant errors are not the important ones, because they can be very easily adjusted for by changing the position of the sights on the gun. The really important errors are the variable errors. No correction of the sights on A's gun will make all of his shots fall in the center. He is inherently much too variable." (Chapanis, 1951, p. 1187)
Figure 2.4 Distribution of rifle shots. Rifleman A has a small constant error (CE) and large variable error (VE). Rifleman B has a large CE bias, but a small VE.
Reprinted, by permission, from A. Chapanis, 1951, "Theory and methods for analyzing errors in man-machine systems," Annals of the New York Academy of Sciences 51: 1181.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Visual proprioception
Figure 5.4 illustrates one of James Gibson’s concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979).
Figure 5.4 illustrates one of James Gibson's concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979). The pattern of rays experienced is called the optical array, and it provides a unique specification of the location of the eye in space. The changes in the optical array when the eye is moved from one place to another are called the optical flow, implying that the visual environment "flows past us" as we move around. An important point is that the particular patterns of flow specify distinct kinds of movements of the eyes with respect to the environment. For example, if the angle between the light rays from two sides of an object is constant over time, this specifies that you are not moving with respect to that object. If the angle between these rays is increasing, then you are moving toward the object; if it is decreasing, you are moving away from it. Also, if the angles from two sides of an object (with respect to straight ahead) are increasing at the same rate, the eye is moving toward the center of the object (e.g., your eye(s) are moving toward the center of a picture on the wall). In conditions in which the angles from both sides of an object are changing in the same direction, if the rate of increase in the angle of the rays from the right side of the object is greater than the rate of increase from the left side and continues in this way, you will pass the object so that it is on your right side.
Figure 5.4 The detection of distance: The angles of the light rays from the distant pole change less than those from the near pole as the head and eyes are moved.
The optical flow generated as you move in the environment also tells you about the environment itself in ways that could not be achieved if you were stationary. For example, imagine looking out the window at two telephone poles as illustrated in figure 5.4. Which of them is closer? The question is difficult to answer if you remain still, because the poles appear to be nearly the same thickness and height. But if you move your head sideways, you can tell immediately. You will notice that one of the poles seems to "move more quickly" as you change head position. This, of course, is the same as saying that the angles of the rays received from one object changed more quickly (α1 in the figure) than did those from the other (α2), implying that pole 1 is closer than pole 2. Thus, the visual system, through movement of the entire head, body, or both, can provide rich information about the nature of the environment. In this view, vision is not merely an exteroceptive sense, passively providing information about the environment. It is also a proprioceptive sense telling us about our own movements. As well, vision is dependent on movement in some situations for informing us about the environment. In this way, vision and movement are very closely and reciprocally linked. Excellent discussions of this basic idea are found in Gibson (1966, 1979) and Lee (1980; Lee & Young, 1985), the latter showing relevance to many situations, such as sport-related motions and bird flight.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Fundamental distinctions and definitions in motor learning
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill.
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill. This is because psychologists and others tend to use the metaphor of memory as a place where information is stored, such as a computer hard drive or a library. Statements like "I have a good memory for names and dates," or "The person placed the phone number in long-term memory," are representative of this use of the term. The implication is that some set of processes has led to the acquisition of the materials, and now some other set of processes is responsible for keeping them "in" memory.
Memory
A common meaning of the term motor memory is "the persistence of the acquired capability for performance." In this sense, habit and memory are conceptually similar. Remember, the usual test for learning of a task concerns how well the individual can perform the skill on a retention or transfer test. That is, a skill has been learned if and only if it can be retained "relatively permanently" (see chapter 9). If you can still perform a skill after not having practiced it for a year (or even for a day or just a few minutes), then you have a memory of the skill. In this sense, memory is the capability for performance, not a location where that capability is stored. Depending on one's theoretical orientation about motor learning, memory could be a motor program, a reference of correctness, a schema, or an intrinsic coordination pattern (Amazeen, 2002). From this viewpoint, as you can see, learning and memory are just "different sides of the same behavioral coin," as Adams (1976a, p. 223) put it (see also Adams, 1967).
Chapter 9 introduced the motor behavior - memory framework that connects the temporal evolution of motor memory processes and the phases of motor learning (Kantak & Winstein, 2012). Memory researchers describe the information processes as encoding, consolidation, and retrieval. Because learning and memory are just different sides of the same behavioral coin, we can map motor learning processes onto memory processes using this framework. Thus, acquisition or practice corresponds to the encoding processes of a motor memory, and the end-of-practice or immediate retention phase of motor learning corresponds to consolidation processes where the memory is somewhat more fragile, and finally, the delayed retention or transfer phase that represents retrieval processes are referred to as recall. We refer back to these memory processes throughout this chapter as they relate to retention and transfer.
Forgetting
Another term used in this context is forgetting. The term is used to indicate the opposite of learning, in that learning refers to the acquisition of the capability for movement whereas forgetting refers to the loss of such capability. It is likely that the processes and principles having to do with gains and losses in the capability for moving will be different, but the terms refer to the different directions of the change in this capability. "Forgetting" is a term that has to do with theoretical constructs, just as "learning" does. Memory is a construct, and forgetting is the loss of memory; so forgetting is a concept at a theoretical, rather than a behavioral, level of thinking.
As shown in table 13.1, the analogy to the study of learning is a close one. At the theoretical level, learning is a gain in the capability for skilled action, while forgetting is the loss of same. On the behavioral level, learning is evidenced by relatively permanent gains in performance, while forgetting is evidenced by relatively permanent losses in performance, or losses in retention. So, if you understand what measures of behavior suggest about learning, then you also understand the same about forgetting. Remember that we cannot measure forgetting directly; like learning, it must be inferred from performance. As such, an inability to retrieve a specific memory may only reflect a problem with the retrieval mechanism and not the memory itself. A good example of this phenomenon is behavior after head trauma when a loss of memory is evidenced by forgetting. With time, however, the person is usually able to retrieve the information and thereby demonstrate that memory was intact all along but the retrieval processes were temporarily impaired (Coste et al., 2011).
Retention and Transfer
Retention refers to the persistence or lack of persistence of the performance, and is considered at the behavioral level rather than at the theoretical level (table 13.1). It might or might not tell us whether memory has been lost. The test on which decisions about retention are based is called the retention test, performed at a period of time after practice trials have ended (following the retention interval). If performance on the retention test is as proficient as it was immediately after the end of the practice session (or acquisition phase), then we might be inclined to say that no memory loss (no forgetting) has occurred. If performance on the retention test is poor, then we may decide that a memory loss has occurred. However, because the test for memory (the retention test) is a test of performance, it is subject to all the variations that cause performances to change in temporary ways - just as in the study of learning. Thus, it could be that performance is poor on the retention test for some temporary reason (fatigue, anxiety) or a problem with the retrieval processes mentioned earlier, and so one could falsely conclude that a memory loss has occurred. (At this point it might be helpful to review the learning - performance distinction presented in chapter 9.)
For all practical purposes, a retention test and a transfer test are very similar. In both cases, the interest is in the persistence of the acquired capability for performance (habit). The two types of tests differ only in that the transfer test has individuals (all or some) switching to different tasks or conditions, whereas the retention test usually involves retesting people on the same task or conditions.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Using constant error and variable error
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE.
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE. This situation was described years ago by Chapanis (1951) and is illustrated in figure 2.4 (see "The Relative Importance of Constant and Variable Errors"). Which riflemanman, A or B, appears to be the more skilled?
The study of motor learning will show that the measure of error that is most sensitive to the effects of practice is consistency (VE); bias (CE) often changes quickly in the first several trials and remains near zero thereafter, even after years of practice. There are some situations, however, in which CE is preferred to VE; but these are specialized applications. Thus, these two measures of error, CE and VE, seem to represent two distinct aspects of performance - bias and variability, respectively. But sometimes it is more desirable to have a single measure of "overall error" that combines both of these performance indicators rather than using separate measures of accuracy and inconsistency.
The Relative Importance of Constant and Variable Errors
Research Capsule
Alphonse Chapanis was one of the pioneers in the emergence of human factors research. His analysis of errors in movement is as important today as it was over a half century ago.
"Having defined constant and variable errors, we might ask: Which is the more important? Let us return for a moment to the target patterns shot by the two riflemen [figure 2.4]. At first glance, you might say that B is a very inaccurate shooter. And yet any rifleman will tell you that this is not the case at all. B is a much better shooter than A. The reason is this: The large constant error in the trial shots fired by B can be compensated for very easily by simple adjustments in his sights. With suitable corrections in elevation and windage, rifleman B will turn in a perfect score. In rifle shooting, then, constant errors are not the important ones, because they can be very easily adjusted for by changing the position of the sights on the gun. The really important errors are the variable errors. No correction of the sights on A's gun will make all of his shots fall in the center. He is inherently much too variable." (Chapanis, 1951, p. 1187)
Figure 2.4 Distribution of rifle shots. Rifleman A has a small constant error (CE) and large variable error (VE). Rifleman B has a large CE bias, but a small VE.
Reprinted, by permission, from A. Chapanis, 1951, "Theory and methods for analyzing errors in man-machine systems," Annals of the New York Academy of Sciences 51: 1181.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Visual proprioception
Figure 5.4 illustrates one of James Gibson’s concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979).
Figure 5.4 illustrates one of James Gibson's concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979). The pattern of rays experienced is called the optical array, and it provides a unique specification of the location of the eye in space. The changes in the optical array when the eye is moved from one place to another are called the optical flow, implying that the visual environment "flows past us" as we move around. An important point is that the particular patterns of flow specify distinct kinds of movements of the eyes with respect to the environment. For example, if the angle between the light rays from two sides of an object is constant over time, this specifies that you are not moving with respect to that object. If the angle between these rays is increasing, then you are moving toward the object; if it is decreasing, you are moving away from it. Also, if the angles from two sides of an object (with respect to straight ahead) are increasing at the same rate, the eye is moving toward the center of the object (e.g., your eye(s) are moving toward the center of a picture on the wall). In conditions in which the angles from both sides of an object are changing in the same direction, if the rate of increase in the angle of the rays from the right side of the object is greater than the rate of increase from the left side and continues in this way, you will pass the object so that it is on your right side.
Figure 5.4 The detection of distance: The angles of the light rays from the distant pole change less than those from the near pole as the head and eyes are moved.
The optical flow generated as you move in the environment also tells you about the environment itself in ways that could not be achieved if you were stationary. For example, imagine looking out the window at two telephone poles as illustrated in figure 5.4. Which of them is closer? The question is difficult to answer if you remain still, because the poles appear to be nearly the same thickness and height. But if you move your head sideways, you can tell immediately. You will notice that one of the poles seems to "move more quickly" as you change head position. This, of course, is the same as saying that the angles of the rays received from one object changed more quickly (α1 in the figure) than did those from the other (α2), implying that pole 1 is closer than pole 2. Thus, the visual system, through movement of the entire head, body, or both, can provide rich information about the nature of the environment. In this view, vision is not merely an exteroceptive sense, passively providing information about the environment. It is also a proprioceptive sense telling us about our own movements. As well, vision is dependent on movement in some situations for informing us about the environment. In this way, vision and movement are very closely and reciprocally linked. Excellent discussions of this basic idea are found in Gibson (1966, 1979) and Lee (1980; Lee & Young, 1985), the latter showing relevance to many situations, such as sport-related motions and bird flight.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Fundamental distinctions and definitions in motor learning
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill.
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill. This is because psychologists and others tend to use the metaphor of memory as a place where information is stored, such as a computer hard drive or a library. Statements like "I have a good memory for names and dates," or "The person placed the phone number in long-term memory," are representative of this use of the term. The implication is that some set of processes has led to the acquisition of the materials, and now some other set of processes is responsible for keeping them "in" memory.
Memory
A common meaning of the term motor memory is "the persistence of the acquired capability for performance." In this sense, habit and memory are conceptually similar. Remember, the usual test for learning of a task concerns how well the individual can perform the skill on a retention or transfer test. That is, a skill has been learned if and only if it can be retained "relatively permanently" (see chapter 9). If you can still perform a skill after not having practiced it for a year (or even for a day or just a few minutes), then you have a memory of the skill. In this sense, memory is the capability for performance, not a location where that capability is stored. Depending on one's theoretical orientation about motor learning, memory could be a motor program, a reference of correctness, a schema, or an intrinsic coordination pattern (Amazeen, 2002). From this viewpoint, as you can see, learning and memory are just "different sides of the same behavioral coin," as Adams (1976a, p. 223) put it (see also Adams, 1967).
Chapter 9 introduced the motor behavior - memory framework that connects the temporal evolution of motor memory processes and the phases of motor learning (Kantak & Winstein, 2012). Memory researchers describe the information processes as encoding, consolidation, and retrieval. Because learning and memory are just different sides of the same behavioral coin, we can map motor learning processes onto memory processes using this framework. Thus, acquisition or practice corresponds to the encoding processes of a motor memory, and the end-of-practice or immediate retention phase of motor learning corresponds to consolidation processes where the memory is somewhat more fragile, and finally, the delayed retention or transfer phase that represents retrieval processes are referred to as recall. We refer back to these memory processes throughout this chapter as they relate to retention and transfer.
Forgetting
Another term used in this context is forgetting. The term is used to indicate the opposite of learning, in that learning refers to the acquisition of the capability for movement whereas forgetting refers to the loss of such capability. It is likely that the processes and principles having to do with gains and losses in the capability for moving will be different, but the terms refer to the different directions of the change in this capability. "Forgetting" is a term that has to do with theoretical constructs, just as "learning" does. Memory is a construct, and forgetting is the loss of memory; so forgetting is a concept at a theoretical, rather than a behavioral, level of thinking.
As shown in table 13.1, the analogy to the study of learning is a close one. At the theoretical level, learning is a gain in the capability for skilled action, while forgetting is the loss of same. On the behavioral level, learning is evidenced by relatively permanent gains in performance, while forgetting is evidenced by relatively permanent losses in performance, or losses in retention. So, if you understand what measures of behavior suggest about learning, then you also understand the same about forgetting. Remember that we cannot measure forgetting directly; like learning, it must be inferred from performance. As such, an inability to retrieve a specific memory may only reflect a problem with the retrieval mechanism and not the memory itself. A good example of this phenomenon is behavior after head trauma when a loss of memory is evidenced by forgetting. With time, however, the person is usually able to retrieve the information and thereby demonstrate that memory was intact all along but the retrieval processes were temporarily impaired (Coste et al., 2011).
Retention and Transfer
Retention refers to the persistence or lack of persistence of the performance, and is considered at the behavioral level rather than at the theoretical level (table 13.1). It might or might not tell us whether memory has been lost. The test on which decisions about retention are based is called the retention test, performed at a period of time after practice trials have ended (following the retention interval). If performance on the retention test is as proficient as it was immediately after the end of the practice session (or acquisition phase), then we might be inclined to say that no memory loss (no forgetting) has occurred. If performance on the retention test is poor, then we may decide that a memory loss has occurred. However, because the test for memory (the retention test) is a test of performance, it is subject to all the variations that cause performances to change in temporary ways - just as in the study of learning. Thus, it could be that performance is poor on the retention test for some temporary reason (fatigue, anxiety) or a problem with the retrieval processes mentioned earlier, and so one could falsely conclude that a memory loss has occurred. (At this point it might be helpful to review the learning - performance distinction presented in chapter 9.)
For all practical purposes, a retention test and a transfer test are very similar. In both cases, the interest is in the persistence of the acquired capability for performance (habit). The two types of tests differ only in that the transfer test has individuals (all or some) switching to different tasks or conditions, whereas the retention test usually involves retesting people on the same task or conditions.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Using constant error and variable error
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE.
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE. This situation was described years ago by Chapanis (1951) and is illustrated in figure 2.4 (see "The Relative Importance of Constant and Variable Errors"). Which riflemanman, A or B, appears to be the more skilled?
The study of motor learning will show that the measure of error that is most sensitive to the effects of practice is consistency (VE); bias (CE) often changes quickly in the first several trials and remains near zero thereafter, even after years of practice. There are some situations, however, in which CE is preferred to VE; but these are specialized applications. Thus, these two measures of error, CE and VE, seem to represent two distinct aspects of performance - bias and variability, respectively. But sometimes it is more desirable to have a single measure of "overall error" that combines both of these performance indicators rather than using separate measures of accuracy and inconsistency.
The Relative Importance of Constant and Variable Errors
Research Capsule
Alphonse Chapanis was one of the pioneers in the emergence of human factors research. His analysis of errors in movement is as important today as it was over a half century ago.
"Having defined constant and variable errors, we might ask: Which is the more important? Let us return for a moment to the target patterns shot by the two riflemen [figure 2.4]. At first glance, you might say that B is a very inaccurate shooter. And yet any rifleman will tell you that this is not the case at all. B is a much better shooter than A. The reason is this: The large constant error in the trial shots fired by B can be compensated for very easily by simple adjustments in his sights. With suitable corrections in elevation and windage, rifleman B will turn in a perfect score. In rifle shooting, then, constant errors are not the important ones, because they can be very easily adjusted for by changing the position of the sights on the gun. The really important errors are the variable errors. No correction of the sights on A's gun will make all of his shots fall in the center. He is inherently much too variable." (Chapanis, 1951, p. 1187)
Figure 2.4 Distribution of rifle shots. Rifleman A has a small constant error (CE) and large variable error (VE). Rifleman B has a large CE bias, but a small VE.
Reprinted, by permission, from A. Chapanis, 1951, "Theory and methods for analyzing errors in man-machine systems," Annals of the New York Academy of Sciences 51: 1181.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Visual proprioception
Figure 5.4 illustrates one of James Gibson’s concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979).
Figure 5.4 illustrates one of James Gibson's concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979). The pattern of rays experienced is called the optical array, and it provides a unique specification of the location of the eye in space. The changes in the optical array when the eye is moved from one place to another are called the optical flow, implying that the visual environment "flows past us" as we move around. An important point is that the particular patterns of flow specify distinct kinds of movements of the eyes with respect to the environment. For example, if the angle between the light rays from two sides of an object is constant over time, this specifies that you are not moving with respect to that object. If the angle between these rays is increasing, then you are moving toward the object; if it is decreasing, you are moving away from it. Also, if the angles from two sides of an object (with respect to straight ahead) are increasing at the same rate, the eye is moving toward the center of the object (e.g., your eye(s) are moving toward the center of a picture on the wall). In conditions in which the angles from both sides of an object are changing in the same direction, if the rate of increase in the angle of the rays from the right side of the object is greater than the rate of increase from the left side and continues in this way, you will pass the object so that it is on your right side.
Figure 5.4 The detection of distance: The angles of the light rays from the distant pole change less than those from the near pole as the head and eyes are moved.
The optical flow generated as you move in the environment also tells you about the environment itself in ways that could not be achieved if you were stationary. For example, imagine looking out the window at two telephone poles as illustrated in figure 5.4. Which of them is closer? The question is difficult to answer if you remain still, because the poles appear to be nearly the same thickness and height. But if you move your head sideways, you can tell immediately. You will notice that one of the poles seems to "move more quickly" as you change head position. This, of course, is the same as saying that the angles of the rays received from one object changed more quickly (α1 in the figure) than did those from the other (α2), implying that pole 1 is closer than pole 2. Thus, the visual system, through movement of the entire head, body, or both, can provide rich information about the nature of the environment. In this view, vision is not merely an exteroceptive sense, passively providing information about the environment. It is also a proprioceptive sense telling us about our own movements. As well, vision is dependent on movement in some situations for informing us about the environment. In this way, vision and movement are very closely and reciprocally linked. Excellent discussions of this basic idea are found in Gibson (1966, 1979) and Lee (1980; Lee & Young, 1985), the latter showing relevance to many situations, such as sport-related motions and bird flight.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Fundamental distinctions and definitions in motor learning
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill.
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill. This is because psychologists and others tend to use the metaphor of memory as a place where information is stored, such as a computer hard drive or a library. Statements like "I have a good memory for names and dates," or "The person placed the phone number in long-term memory," are representative of this use of the term. The implication is that some set of processes has led to the acquisition of the materials, and now some other set of processes is responsible for keeping them "in" memory.
Memory
A common meaning of the term motor memory is "the persistence of the acquired capability for performance." In this sense, habit and memory are conceptually similar. Remember, the usual test for learning of a task concerns how well the individual can perform the skill on a retention or transfer test. That is, a skill has been learned if and only if it can be retained "relatively permanently" (see chapter 9). If you can still perform a skill after not having practiced it for a year (or even for a day or just a few minutes), then you have a memory of the skill. In this sense, memory is the capability for performance, not a location where that capability is stored. Depending on one's theoretical orientation about motor learning, memory could be a motor program, a reference of correctness, a schema, or an intrinsic coordination pattern (Amazeen, 2002). From this viewpoint, as you can see, learning and memory are just "different sides of the same behavioral coin," as Adams (1976a, p. 223) put it (see also Adams, 1967).
Chapter 9 introduced the motor behavior - memory framework that connects the temporal evolution of motor memory processes and the phases of motor learning (Kantak & Winstein, 2012). Memory researchers describe the information processes as encoding, consolidation, and retrieval. Because learning and memory are just different sides of the same behavioral coin, we can map motor learning processes onto memory processes using this framework. Thus, acquisition or practice corresponds to the encoding processes of a motor memory, and the end-of-practice or immediate retention phase of motor learning corresponds to consolidation processes where the memory is somewhat more fragile, and finally, the delayed retention or transfer phase that represents retrieval processes are referred to as recall. We refer back to these memory processes throughout this chapter as they relate to retention and transfer.
Forgetting
Another term used in this context is forgetting. The term is used to indicate the opposite of learning, in that learning refers to the acquisition of the capability for movement whereas forgetting refers to the loss of such capability. It is likely that the processes and principles having to do with gains and losses in the capability for moving will be different, but the terms refer to the different directions of the change in this capability. "Forgetting" is a term that has to do with theoretical constructs, just as "learning" does. Memory is a construct, and forgetting is the loss of memory; so forgetting is a concept at a theoretical, rather than a behavioral, level of thinking.
As shown in table 13.1, the analogy to the study of learning is a close one. At the theoretical level, learning is a gain in the capability for skilled action, while forgetting is the loss of same. On the behavioral level, learning is evidenced by relatively permanent gains in performance, while forgetting is evidenced by relatively permanent losses in performance, or losses in retention. So, if you understand what measures of behavior suggest about learning, then you also understand the same about forgetting. Remember that we cannot measure forgetting directly; like learning, it must be inferred from performance. As such, an inability to retrieve a specific memory may only reflect a problem with the retrieval mechanism and not the memory itself. A good example of this phenomenon is behavior after head trauma when a loss of memory is evidenced by forgetting. With time, however, the person is usually able to retrieve the information and thereby demonstrate that memory was intact all along but the retrieval processes were temporarily impaired (Coste et al., 2011).
Retention and Transfer
Retention refers to the persistence or lack of persistence of the performance, and is considered at the behavioral level rather than at the theoretical level (table 13.1). It might or might not tell us whether memory has been lost. The test on which decisions about retention are based is called the retention test, performed at a period of time after practice trials have ended (following the retention interval). If performance on the retention test is as proficient as it was immediately after the end of the practice session (or acquisition phase), then we might be inclined to say that no memory loss (no forgetting) has occurred. If performance on the retention test is poor, then we may decide that a memory loss has occurred. However, because the test for memory (the retention test) is a test of performance, it is subject to all the variations that cause performances to change in temporary ways - just as in the study of learning. Thus, it could be that performance is poor on the retention test for some temporary reason (fatigue, anxiety) or a problem with the retrieval processes mentioned earlier, and so one could falsely conclude that a memory loss has occurred. (At this point it might be helpful to review the learning - performance distinction presented in chapter 9.)
For all practical purposes, a retention test and a transfer test are very similar. In both cases, the interest is in the persistence of the acquired capability for performance (habit). The two types of tests differ only in that the transfer test has individuals (all or some) switching to different tasks or conditions, whereas the retention test usually involves retesting people on the same task or conditions.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Using constant error and variable error
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE.
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE. This situation was described years ago by Chapanis (1951) and is illustrated in figure 2.4 (see "The Relative Importance of Constant and Variable Errors"). Which riflemanman, A or B, appears to be the more skilled?
The study of motor learning will show that the measure of error that is most sensitive to the effects of practice is consistency (VE); bias (CE) often changes quickly in the first several trials and remains near zero thereafter, even after years of practice. There are some situations, however, in which CE is preferred to VE; but these are specialized applications. Thus, these two measures of error, CE and VE, seem to represent two distinct aspects of performance - bias and variability, respectively. But sometimes it is more desirable to have a single measure of "overall error" that combines both of these performance indicators rather than using separate measures of accuracy and inconsistency.
The Relative Importance of Constant and Variable Errors
Research Capsule
Alphonse Chapanis was one of the pioneers in the emergence of human factors research. His analysis of errors in movement is as important today as it was over a half century ago.
"Having defined constant and variable errors, we might ask: Which is the more important? Let us return for a moment to the target patterns shot by the two riflemen [figure 2.4]. At first glance, you might say that B is a very inaccurate shooter. And yet any rifleman will tell you that this is not the case at all. B is a much better shooter than A. The reason is this: The large constant error in the trial shots fired by B can be compensated for very easily by simple adjustments in his sights. With suitable corrections in elevation and windage, rifleman B will turn in a perfect score. In rifle shooting, then, constant errors are not the important ones, because they can be very easily adjusted for by changing the position of the sights on the gun. The really important errors are the variable errors. No correction of the sights on A's gun will make all of his shots fall in the center. He is inherently much too variable." (Chapanis, 1951, p. 1187)
Figure 2.4 Distribution of rifle shots. Rifleman A has a small constant error (CE) and large variable error (VE). Rifleman B has a large CE bias, but a small VE.
Reprinted, by permission, from A. Chapanis, 1951, "Theory and methods for analyzing errors in man-machine systems," Annals of the New York Academy of Sciences 51: 1181.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Visual proprioception
Figure 5.4 illustrates one of James Gibson’s concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979).
Figure 5.4 illustrates one of James Gibson's concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979). The pattern of rays experienced is called the optical array, and it provides a unique specification of the location of the eye in space. The changes in the optical array when the eye is moved from one place to another are called the optical flow, implying that the visual environment "flows past us" as we move around. An important point is that the particular patterns of flow specify distinct kinds of movements of the eyes with respect to the environment. For example, if the angle between the light rays from two sides of an object is constant over time, this specifies that you are not moving with respect to that object. If the angle between these rays is increasing, then you are moving toward the object; if it is decreasing, you are moving away from it. Also, if the angles from two sides of an object (with respect to straight ahead) are increasing at the same rate, the eye is moving toward the center of the object (e.g., your eye(s) are moving toward the center of a picture on the wall). In conditions in which the angles from both sides of an object are changing in the same direction, if the rate of increase in the angle of the rays from the right side of the object is greater than the rate of increase from the left side and continues in this way, you will pass the object so that it is on your right side.
Figure 5.4 The detection of distance: The angles of the light rays from the distant pole change less than those from the near pole as the head and eyes are moved.
The optical flow generated as you move in the environment also tells you about the environment itself in ways that could not be achieved if you were stationary. For example, imagine looking out the window at two telephone poles as illustrated in figure 5.4. Which of them is closer? The question is difficult to answer if you remain still, because the poles appear to be nearly the same thickness and height. But if you move your head sideways, you can tell immediately. You will notice that one of the poles seems to "move more quickly" as you change head position. This, of course, is the same as saying that the angles of the rays received from one object changed more quickly (α1 in the figure) than did those from the other (α2), implying that pole 1 is closer than pole 2. Thus, the visual system, through movement of the entire head, body, or both, can provide rich information about the nature of the environment. In this view, vision is not merely an exteroceptive sense, passively providing information about the environment. It is also a proprioceptive sense telling us about our own movements. As well, vision is dependent on movement in some situations for informing us about the environment. In this way, vision and movement are very closely and reciprocally linked. Excellent discussions of this basic idea are found in Gibson (1966, 1979) and Lee (1980; Lee & Young, 1985), the latter showing relevance to many situations, such as sport-related motions and bird flight.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Fundamental distinctions and definitions in motor learning
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill.
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill. This is because psychologists and others tend to use the metaphor of memory as a place where information is stored, such as a computer hard drive or a library. Statements like "I have a good memory for names and dates," or "The person placed the phone number in long-term memory," are representative of this use of the term. The implication is that some set of processes has led to the acquisition of the materials, and now some other set of processes is responsible for keeping them "in" memory.
Memory
A common meaning of the term motor memory is "the persistence of the acquired capability for performance." In this sense, habit and memory are conceptually similar. Remember, the usual test for learning of a task concerns how well the individual can perform the skill on a retention or transfer test. That is, a skill has been learned if and only if it can be retained "relatively permanently" (see chapter 9). If you can still perform a skill after not having practiced it for a year (or even for a day or just a few minutes), then you have a memory of the skill. In this sense, memory is the capability for performance, not a location where that capability is stored. Depending on one's theoretical orientation about motor learning, memory could be a motor program, a reference of correctness, a schema, or an intrinsic coordination pattern (Amazeen, 2002). From this viewpoint, as you can see, learning and memory are just "different sides of the same behavioral coin," as Adams (1976a, p. 223) put it (see also Adams, 1967).
Chapter 9 introduced the motor behavior - memory framework that connects the temporal evolution of motor memory processes and the phases of motor learning (Kantak & Winstein, 2012). Memory researchers describe the information processes as encoding, consolidation, and retrieval. Because learning and memory are just different sides of the same behavioral coin, we can map motor learning processes onto memory processes using this framework. Thus, acquisition or practice corresponds to the encoding processes of a motor memory, and the end-of-practice or immediate retention phase of motor learning corresponds to consolidation processes where the memory is somewhat more fragile, and finally, the delayed retention or transfer phase that represents retrieval processes are referred to as recall. We refer back to these memory processes throughout this chapter as they relate to retention and transfer.
Forgetting
Another term used in this context is forgetting. The term is used to indicate the opposite of learning, in that learning refers to the acquisition of the capability for movement whereas forgetting refers to the loss of such capability. It is likely that the processes and principles having to do with gains and losses in the capability for moving will be different, but the terms refer to the different directions of the change in this capability. "Forgetting" is a term that has to do with theoretical constructs, just as "learning" does. Memory is a construct, and forgetting is the loss of memory; so forgetting is a concept at a theoretical, rather than a behavioral, level of thinking.
As shown in table 13.1, the analogy to the study of learning is a close one. At the theoretical level, learning is a gain in the capability for skilled action, while forgetting is the loss of same. On the behavioral level, learning is evidenced by relatively permanent gains in performance, while forgetting is evidenced by relatively permanent losses in performance, or losses in retention. So, if you understand what measures of behavior suggest about learning, then you also understand the same about forgetting. Remember that we cannot measure forgetting directly; like learning, it must be inferred from performance. As such, an inability to retrieve a specific memory may only reflect a problem with the retrieval mechanism and not the memory itself. A good example of this phenomenon is behavior after head trauma when a loss of memory is evidenced by forgetting. With time, however, the person is usually able to retrieve the information and thereby demonstrate that memory was intact all along but the retrieval processes were temporarily impaired (Coste et al., 2011).
Retention and Transfer
Retention refers to the persistence or lack of persistence of the performance, and is considered at the behavioral level rather than at the theoretical level (table 13.1). It might or might not tell us whether memory has been lost. The test on which decisions about retention are based is called the retention test, performed at a period of time after practice trials have ended (following the retention interval). If performance on the retention test is as proficient as it was immediately after the end of the practice session (or acquisition phase), then we might be inclined to say that no memory loss (no forgetting) has occurred. If performance on the retention test is poor, then we may decide that a memory loss has occurred. However, because the test for memory (the retention test) is a test of performance, it is subject to all the variations that cause performances to change in temporary ways - just as in the study of learning. Thus, it could be that performance is poor on the retention test for some temporary reason (fatigue, anxiety) or a problem with the retrieval processes mentioned earlier, and so one could falsely conclude that a memory loss has occurred. (At this point it might be helpful to review the learning - performance distinction presented in chapter 9.)
For all practical purposes, a retention test and a transfer test are very similar. In both cases, the interest is in the persistence of the acquired capability for performance (habit). The two types of tests differ only in that the transfer test has individuals (all or some) switching to different tasks or conditions, whereas the retention test usually involves retesting people on the same task or conditions.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Using constant error and variable error
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE.
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE. This situation was described years ago by Chapanis (1951) and is illustrated in figure 2.4 (see "The Relative Importance of Constant and Variable Errors"). Which riflemanman, A or B, appears to be the more skilled?
The study of motor learning will show that the measure of error that is most sensitive to the effects of practice is consistency (VE); bias (CE) often changes quickly in the first several trials and remains near zero thereafter, even after years of practice. There are some situations, however, in which CE is preferred to VE; but these are specialized applications. Thus, these two measures of error, CE and VE, seem to represent two distinct aspects of performance - bias and variability, respectively. But sometimes it is more desirable to have a single measure of "overall error" that combines both of these performance indicators rather than using separate measures of accuracy and inconsistency.
The Relative Importance of Constant and Variable Errors
Research Capsule
Alphonse Chapanis was one of the pioneers in the emergence of human factors research. His analysis of errors in movement is as important today as it was over a half century ago.
"Having defined constant and variable errors, we might ask: Which is the more important? Let us return for a moment to the target patterns shot by the two riflemen [figure 2.4]. At first glance, you might say that B is a very inaccurate shooter. And yet any rifleman will tell you that this is not the case at all. B is a much better shooter than A. The reason is this: The large constant error in the trial shots fired by B can be compensated for very easily by simple adjustments in his sights. With suitable corrections in elevation and windage, rifleman B will turn in a perfect score. In rifle shooting, then, constant errors are not the important ones, because they can be very easily adjusted for by changing the position of the sights on the gun. The really important errors are the variable errors. No correction of the sights on A's gun will make all of his shots fall in the center. He is inherently much too variable." (Chapanis, 1951, p. 1187)
Figure 2.4 Distribution of rifle shots. Rifleman A has a small constant error (CE) and large variable error (VE). Rifleman B has a large CE bias, but a small VE.
Reprinted, by permission, from A. Chapanis, 1951, "Theory and methods for analyzing errors in man-machine systems," Annals of the New York Academy of Sciences 51: 1181.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Visual proprioception
Figure 5.4 illustrates one of James Gibson’s concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979).
Figure 5.4 illustrates one of James Gibson's concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979). The pattern of rays experienced is called the optical array, and it provides a unique specification of the location of the eye in space. The changes in the optical array when the eye is moved from one place to another are called the optical flow, implying that the visual environment "flows past us" as we move around. An important point is that the particular patterns of flow specify distinct kinds of movements of the eyes with respect to the environment. For example, if the angle between the light rays from two sides of an object is constant over time, this specifies that you are not moving with respect to that object. If the angle between these rays is increasing, then you are moving toward the object; if it is decreasing, you are moving away from it. Also, if the angles from two sides of an object (with respect to straight ahead) are increasing at the same rate, the eye is moving toward the center of the object (e.g., your eye(s) are moving toward the center of a picture on the wall). In conditions in which the angles from both sides of an object are changing in the same direction, if the rate of increase in the angle of the rays from the right side of the object is greater than the rate of increase from the left side and continues in this way, you will pass the object so that it is on your right side.
Figure 5.4 The detection of distance: The angles of the light rays from the distant pole change less than those from the near pole as the head and eyes are moved.
The optical flow generated as you move in the environment also tells you about the environment itself in ways that could not be achieved if you were stationary. For example, imagine looking out the window at two telephone poles as illustrated in figure 5.4. Which of them is closer? The question is difficult to answer if you remain still, because the poles appear to be nearly the same thickness and height. But if you move your head sideways, you can tell immediately. You will notice that one of the poles seems to "move more quickly" as you change head position. This, of course, is the same as saying that the angles of the rays received from one object changed more quickly (α1 in the figure) than did those from the other (α2), implying that pole 1 is closer than pole 2. Thus, the visual system, through movement of the entire head, body, or both, can provide rich information about the nature of the environment. In this view, vision is not merely an exteroceptive sense, passively providing information about the environment. It is also a proprioceptive sense telling us about our own movements. As well, vision is dependent on movement in some situations for informing us about the environment. In this way, vision and movement are very closely and reciprocally linked. Excellent discussions of this basic idea are found in Gibson (1966, 1979) and Lee (1980; Lee & Young, 1985), the latter showing relevance to many situations, such as sport-related motions and bird flight.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Fundamental distinctions and definitions in motor learning
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill.
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill. This is because psychologists and others tend to use the metaphor of memory as a place where information is stored, such as a computer hard drive or a library. Statements like "I have a good memory for names and dates," or "The person placed the phone number in long-term memory," are representative of this use of the term. The implication is that some set of processes has led to the acquisition of the materials, and now some other set of processes is responsible for keeping them "in" memory.
Memory
A common meaning of the term motor memory is "the persistence of the acquired capability for performance." In this sense, habit and memory are conceptually similar. Remember, the usual test for learning of a task concerns how well the individual can perform the skill on a retention or transfer test. That is, a skill has been learned if and only if it can be retained "relatively permanently" (see chapter 9). If you can still perform a skill after not having practiced it for a year (or even for a day or just a few minutes), then you have a memory of the skill. In this sense, memory is the capability for performance, not a location where that capability is stored. Depending on one's theoretical orientation about motor learning, memory could be a motor program, a reference of correctness, a schema, or an intrinsic coordination pattern (Amazeen, 2002). From this viewpoint, as you can see, learning and memory are just "different sides of the same behavioral coin," as Adams (1976a, p. 223) put it (see also Adams, 1967).
Chapter 9 introduced the motor behavior - memory framework that connects the temporal evolution of motor memory processes and the phases of motor learning (Kantak & Winstein, 2012). Memory researchers describe the information processes as encoding, consolidation, and retrieval. Because learning and memory are just different sides of the same behavioral coin, we can map motor learning processes onto memory processes using this framework. Thus, acquisition or practice corresponds to the encoding processes of a motor memory, and the end-of-practice or immediate retention phase of motor learning corresponds to consolidation processes where the memory is somewhat more fragile, and finally, the delayed retention or transfer phase that represents retrieval processes are referred to as recall. We refer back to these memory processes throughout this chapter as they relate to retention and transfer.
Forgetting
Another term used in this context is forgetting. The term is used to indicate the opposite of learning, in that learning refers to the acquisition of the capability for movement whereas forgetting refers to the loss of such capability. It is likely that the processes and principles having to do with gains and losses in the capability for moving will be different, but the terms refer to the different directions of the change in this capability. "Forgetting" is a term that has to do with theoretical constructs, just as "learning" does. Memory is a construct, and forgetting is the loss of memory; so forgetting is a concept at a theoretical, rather than a behavioral, level of thinking.
As shown in table 13.1, the analogy to the study of learning is a close one. At the theoretical level, learning is a gain in the capability for skilled action, while forgetting is the loss of same. On the behavioral level, learning is evidenced by relatively permanent gains in performance, while forgetting is evidenced by relatively permanent losses in performance, or losses in retention. So, if you understand what measures of behavior suggest about learning, then you also understand the same about forgetting. Remember that we cannot measure forgetting directly; like learning, it must be inferred from performance. As such, an inability to retrieve a specific memory may only reflect a problem with the retrieval mechanism and not the memory itself. A good example of this phenomenon is behavior after head trauma when a loss of memory is evidenced by forgetting. With time, however, the person is usually able to retrieve the information and thereby demonstrate that memory was intact all along but the retrieval processes were temporarily impaired (Coste et al., 2011).
Retention and Transfer
Retention refers to the persistence or lack of persistence of the performance, and is considered at the behavioral level rather than at the theoretical level (table 13.1). It might or might not tell us whether memory has been lost. The test on which decisions about retention are based is called the retention test, performed at a period of time after practice trials have ended (following the retention interval). If performance on the retention test is as proficient as it was immediately after the end of the practice session (or acquisition phase), then we might be inclined to say that no memory loss (no forgetting) has occurred. If performance on the retention test is poor, then we may decide that a memory loss has occurred. However, because the test for memory (the retention test) is a test of performance, it is subject to all the variations that cause performances to change in temporary ways - just as in the study of learning. Thus, it could be that performance is poor on the retention test for some temporary reason (fatigue, anxiety) or a problem with the retrieval processes mentioned earlier, and so one could falsely conclude that a memory loss has occurred. (At this point it might be helpful to review the learning - performance distinction presented in chapter 9.)
For all practical purposes, a retention test and a transfer test are very similar. In both cases, the interest is in the persistence of the acquired capability for performance (habit). The two types of tests differ only in that the transfer test has individuals (all or some) switching to different tasks or conditions, whereas the retention test usually involves retesting people on the same task or conditions.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Using constant error and variable error
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE.
An additional aspect of error scores is important from the point of view not only of research but also of practical application. Compare two riflemen: Rifleman A has a large VE and small CE, whereas rifleman B has a small VE and large CE. This situation was described years ago by Chapanis (1951) and is illustrated in figure 2.4 (see "The Relative Importance of Constant and Variable Errors"). Which riflemanman, A or B, appears to be the more skilled?
The study of motor learning will show that the measure of error that is most sensitive to the effects of practice is consistency (VE); bias (CE) often changes quickly in the first several trials and remains near zero thereafter, even after years of practice. There are some situations, however, in which CE is preferred to VE; but these are specialized applications. Thus, these two measures of error, CE and VE, seem to represent two distinct aspects of performance - bias and variability, respectively. But sometimes it is more desirable to have a single measure of "overall error" that combines both of these performance indicators rather than using separate measures of accuracy and inconsistency.
The Relative Importance of Constant and Variable Errors
Research Capsule
Alphonse Chapanis was one of the pioneers in the emergence of human factors research. His analysis of errors in movement is as important today as it was over a half century ago.
"Having defined constant and variable errors, we might ask: Which is the more important? Let us return for a moment to the target patterns shot by the two riflemen [figure 2.4]. At first glance, you might say that B is a very inaccurate shooter. And yet any rifleman will tell you that this is not the case at all. B is a much better shooter than A. The reason is this: The large constant error in the trial shots fired by B can be compensated for very easily by simple adjustments in his sights. With suitable corrections in elevation and windage, rifleman B will turn in a perfect score. In rifle shooting, then, constant errors are not the important ones, because they can be very easily adjusted for by changing the position of the sights on the gun. The really important errors are the variable errors. No correction of the sights on A's gun will make all of his shots fall in the center. He is inherently much too variable." (Chapanis, 1951, p. 1187)
Figure 2.4 Distribution of rifle shots. Rifleman A has a small constant error (CE) and large variable error (VE). Rifleman B has a large CE bias, but a small VE.
Reprinted, by permission, from A. Chapanis, 1951, "Theory and methods for analyzing errors in man-machine systems," Annals of the New York Academy of Sciences 51: 1181.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Visual proprioception
Figure 5.4 illustrates one of James Gibson’s concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979).
Figure 5.4 illustrates one of James Gibson's concepts about how changes in head position contribute to changes in the angles of light rays entering the eye (Gibson, 1966, 1979). The pattern of rays experienced is called the optical array, and it provides a unique specification of the location of the eye in space. The changes in the optical array when the eye is moved from one place to another are called the optical flow, implying that the visual environment "flows past us" as we move around. An important point is that the particular patterns of flow specify distinct kinds of movements of the eyes with respect to the environment. For example, if the angle between the light rays from two sides of an object is constant over time, this specifies that you are not moving with respect to that object. If the angle between these rays is increasing, then you are moving toward the object; if it is decreasing, you are moving away from it. Also, if the angles from two sides of an object (with respect to straight ahead) are increasing at the same rate, the eye is moving toward the center of the object (e.g., your eye(s) are moving toward the center of a picture on the wall). In conditions in which the angles from both sides of an object are changing in the same direction, if the rate of increase in the angle of the rays from the right side of the object is greater than the rate of increase from the left side and continues in this way, you will pass the object so that it is on your right side.
Figure 5.4 The detection of distance: The angles of the light rays from the distant pole change less than those from the near pole as the head and eyes are moved.
The optical flow generated as you move in the environment also tells you about the environment itself in ways that could not be achieved if you were stationary. For example, imagine looking out the window at two telephone poles as illustrated in figure 5.4. Which of them is closer? The question is difficult to answer if you remain still, because the poles appear to be nearly the same thickness and height. But if you move your head sideways, you can tell immediately. You will notice that one of the poles seems to "move more quickly" as you change head position. This, of course, is the same as saying that the angles of the rays received from one object changed more quickly (α1 in the figure) than did those from the other (α2), implying that pole 1 is closer than pole 2. Thus, the visual system, through movement of the entire head, body, or both, can provide rich information about the nature of the environment. In this view, vision is not merely an exteroceptive sense, passively providing information about the environment. It is also a proprioceptive sense telling us about our own movements. As well, vision is dependent on movement in some situations for informing us about the environment. In this way, vision and movement are very closely and reciprocally linked. Excellent discussions of this basic idea are found in Gibson (1966, 1979) and Lee (1980; Lee & Young, 1985), the latter showing relevance to many situations, such as sport-related motions and bird flight.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Fundamental distinctions and definitions in motor learning
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill.
You may have the impression that motor learning and motor memory are two different aspects of the same problem, one having to do with gains in skill, the other with maintenance of skill. This is because psychologists and others tend to use the metaphor of memory as a place where information is stored, such as a computer hard drive or a library. Statements like "I have a good memory for names and dates," or "The person placed the phone number in long-term memory," are representative of this use of the term. The implication is that some set of processes has led to the acquisition of the materials, and now some other set of processes is responsible for keeping them "in" memory.
Memory
A common meaning of the term motor memory is "the persistence of the acquired capability for performance." In this sense, habit and memory are conceptually similar. Remember, the usual test for learning of a task concerns how well the individual can perform the skill on a retention or transfer test. That is, a skill has been learned if and only if it can be retained "relatively permanently" (see chapter 9). If you can still perform a skill after not having practiced it for a year (or even for a day or just a few minutes), then you have a memory of the skill. In this sense, memory is the capability for performance, not a location where that capability is stored. Depending on one's theoretical orientation about motor learning, memory could be a motor program, a reference of correctness, a schema, or an intrinsic coordination pattern (Amazeen, 2002). From this viewpoint, as you can see, learning and memory are just "different sides of the same behavioral coin," as Adams (1976a, p. 223) put it (see also Adams, 1967).
Chapter 9 introduced the motor behavior - memory framework that connects the temporal evolution of motor memory processes and the phases of motor learning (Kantak & Winstein, 2012). Memory researchers describe the information processes as encoding, consolidation, and retrieval. Because learning and memory are just different sides of the same behavioral coin, we can map motor learning processes onto memory processes using this framework. Thus, acquisition or practice corresponds to the encoding processes of a motor memory, and the end-of-practice or immediate retention phase of motor learning corresponds to consolidation processes where the memory is somewhat more fragile, and finally, the delayed retention or transfer phase that represents retrieval processes are referred to as recall. We refer back to these memory processes throughout this chapter as they relate to retention and transfer.
Forgetting
Another term used in this context is forgetting. The term is used to indicate the opposite of learning, in that learning refers to the acquisition of the capability for movement whereas forgetting refers to the loss of such capability. It is likely that the processes and principles having to do with gains and losses in the capability for moving will be different, but the terms refer to the different directions of the change in this capability. "Forgetting" is a term that has to do with theoretical constructs, just as "learning" does. Memory is a construct, and forgetting is the loss of memory; so forgetting is a concept at a theoretical, rather than a behavioral, level of thinking.
As shown in table 13.1, the analogy to the study of learning is a close one. At the theoretical level, learning is a gain in the capability for skilled action, while forgetting is the loss of same. On the behavioral level, learning is evidenced by relatively permanent gains in performance, while forgetting is evidenced by relatively permanent losses in performance, or losses in retention. So, if you understand what measures of behavior suggest about learning, then you also understand the same about forgetting. Remember that we cannot measure forgetting directly; like learning, it must be inferred from performance. As such, an inability to retrieve a specific memory may only reflect a problem with the retrieval mechanism and not the memory itself. A good example of this phenomenon is behavior after head trauma when a loss of memory is evidenced by forgetting. With time, however, the person is usually able to retrieve the information and thereby demonstrate that memory was intact all along but the retrieval processes were temporarily impaired (Coste et al., 2011).
Retention and Transfer
Retention refers to the persistence or lack of persistence of the performance, and is considered at the behavioral level rather than at the theoretical level (table 13.1). It might or might not tell us whether memory has been lost. The test on which decisions about retention are based is called the retention test, performed at a period of time after practice trials have ended (following the retention interval). If performance on the retention test is as proficient as it was immediately after the end of the practice session (or acquisition phase), then we might be inclined to say that no memory loss (no forgetting) has occurred. If performance on the retention test is poor, then we may decide that a memory loss has occurred. However, because the test for memory (the retention test) is a test of performance, it is subject to all the variations that cause performances to change in temporary ways - just as in the study of learning. Thus, it could be that performance is poor on the retention test for some temporary reason (fatigue, anxiety) or a problem with the retrieval processes mentioned earlier, and so one could falsely conclude that a memory loss has occurred. (At this point it might be helpful to review the learning - performance distinction presented in chapter 9.)
For all practical purposes, a retention test and a transfer test are very similar. In both cases, the interest is in the persistence of the acquired capability for performance (habit). The two types of tests differ only in that the transfer test has individuals (all or some) switching to different tasks or conditions, whereas the retention test usually involves retesting people on the same task or conditions.
Learn more about Motor Control and Learning, Sixth Edition With Web Resource.
Related Books
