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Response-time measurement: A definitive progress report
JOURNAL
OF MATHEMATICAL
PSYCHOLOGY
32, 474477 (1988)
Book
Review
Response-Time Measurement: A Definitive Progress Report R. DUNCAN LUCE. ResponseTimes: Their Role in Inferring Elementary Mental Organization. New York: Oxford Univ. Press, 1986. Pp. xv + 562. $75.00. Reviewed
by RICHARD G. SWENSSON
R. DuncanLute was Alfred North Whitehead Professor of Psychology and now is Victor S. Thomas Professor of Psychology at Harvard University. He received his Ph.D. in mathematics in 1950 from the Massachusetts Institute of Technology, and remained at MIT as a member of the Research Laboratory for Electronics until 1953. Since that time he has held various academic positions, including a Benjamin Franklin Professorship in the Departmentof Psychology at the University of Pennsylvania, a Visiting Professorship of Social Science at the Institute for Advanced Study, Princeton, and Professor of Social Sciences at the University of California at Irvine. He is a member of the National Academy of Science and of the American Academy of Arts and Science, and he was president of the Psychometric Society, 1976-77, and of the Society for Mathematical Psychology, 1979-80. He has published numerous books including Games and decisions: Introduction and critical survey (with H. Raiffa, Wiley. New York, 1957), individual choice behavior: A theoretical analysis (Wiley, New York, 1959), and Foundations of measurement (with D. H. Krantz, P. Suppes, and A. Tversky, Academic Press, San Diego, Vol. I, 1971; Vols. II and III, in press). His current research interests include theoretical work on measurement structures, especially in the areas of utility and risk. The reviewer, Richard G. Swensson, is with the Department of Radiology, Harvard Medical School and Brigham and Women’s Hospital. He obtained his Ph.D. in experimental psychology at the University of Michigan in 1969 and has been on the staff of the Army Behavioral Science Research Laboratory, Washington, DC, and of Bell Telephone Laboratories, Holmdel, New Jersey. His current research interests involve signal detection theory and psychophysics, with applications to radiographic image analysis.
The subtitle of this book conveys Duncan Lute’s view that the goal of studying response time (RT) is to infer the basic organization of mental processes in perceptual and cognitive tasks. Lute believes that these underlying processes can be best understood by developing quantitative theory to describe their characteristics and interaction. Accordingly, his book focuses on formal, analytic models that can interpret and predict measurements of RT and response probability in experimental tasks. But Lute also respects the consensus of empirical data that theory must Requests for reprints should be sent to Richard G. Swensson, Department of Radiology, Harvard Medical School and Brigham and Women’s Hospital, 25 Shattuck St., Boston, MA 02115. 474 0022-2496/88 $3.00 Copyright ,CI 1988 by Academic Press, Inc. All rights of reproductmn m any form reserved.
BOOK
REVIEW
475
explain. The book reviews, and presents in some detail, a careful selection of the important quantitative experimental results in this large and complex field. In addition to a rigorous examination of existing models, and their predictive adequacy, there is considerable thoughtful discussion of the methods (both statistical and experimental) by which theory and data are related. What Lute modestly describes as a “progress report” is a book that systematically integrates present theory with the experimental methods and available data. It represents a definitive review of RT measurement in experimental Psychology. The book has been organized into three major sections that deal with experimental paradigms of increasing task complexity: Detection, Identification, and Matching and Search. In a Detection (e.g., “simple-RT”) Paradigm the subject makes a single response, usually as quickly as possible, to a single reaction signal. An Identification (e.g., “choice-RT”) Paradigm specifies separate responses for each of two or more reaction signals, usually directing the subject to respond both quickly and accurately. Matching and Search Paradigms represent “more cognitive” tasks that map several different signals into the specified responses (often only two). For example, the subject’s response may classify a given signal according to some prespecified mapping (Matching), or it may indicate whether or not any of several signals fall into a specified class (e.g., Visual Search). Despite its focus on RT models, this book can be understood and appreciated by readers with diverse mathematical backgrounds. Much of the material, including substantial discussions of experimental results and methods within each section, demands little beyond logarithms and elementary probability. The formal tools and concepts needed for the more theoretical material are developed, clearly and concisely, in Chapter 1. These are the ideas of probability and random variables used to characterize RT distributions (e.g., by hazard functions and as latency convolutions) and to derive the predictions of various RT models. Even sophistocated readers can profit from this conceptual review; others, if diligent, will find these tools suffjcient for all but a few of the formal derivations. The two largest sections are those on Detection and Identification paradigms, for which quantitative models of RT have been developed in most detail. Separate chapters in these two sections examine the basic empirical results and methods for simple-RT tasks (Chapter 2), for two-choice RT tasks (Chapter 6), and for multiple-alternative RT tasks (Chapter 10). Theoretical issues are the focus of Chapters 3-5 (Detection) and Chapters 7-9 (Identification), which develop the predictions of existing models and examine their adequacy. The section on Matching and Search Paradigms first discusses basic experimental results and methods for memory scanning, visual search and “samedifferent” tasks (Chapter 1 l), together with the models typically used to interpret such data. This is followed by a more mathematical discussion (Chapter 12) of the uniqueness and identifiability of the underlying structures assumed by these “cognitive” models. Lute identifies several reoccurring “themes,” which represent similar effects, methodological problems, and theoretical concerns in both detection and identification paradigms: One is the generally accepted presumption that a measured ao/32:4-9
476
BOOK
REVIEW
RT represents a sum of component latencies: the time consumed by some central “decision” process (the focus of most models) added to a “residual” latency, contributed by a series of peripheral (input and response) processes. Chapter 3 discusses the decomposition of RT into decision and residual-latency components. This is a major theoretical concern for models in detection paradigms, and a methodological problem for models of the decision process in identification paradigms. Another major theme is the pervasive phenomena of subject-controlled tradeoffs, which affect both RT and response probability. The speed-accuracy tradeoff, i.e., an inverse relation between the speed and accuracy of a subject’s responses, is a wellknown result in identification tasks. A similar tradeoff occurs in detection tasks; subjects may vary their “responsiveness,” with faster simple-RTs achieved at a cost of more anticipations or catch-trial responses. Such tradeoffs impose fundamental constraints on models of the decision processes, which must predict a functional relation between the decision’s latency and its “adequacy.” Although empirical tradeoff functions are difficult and tedious to estimate with sufficient precision, they can provide unique information about the structure of the underlying decision processes. Lute uses the predicted form of the speed-accuracy tradeoff function in Identification Paradigms as a major basis for his discussion and comparison of alternative models (Chapters 7-9). A third reoccurring theme is Lute’s discomfort with the rigid temporal structure that most experiments impose on the presentation of signals, i.e., time partitioned into individual trials, but which subjects never encounter outside the laboratory. Experiments that present signals at random intervals in time create the possibility of interactions between successive signals (and responses), however, since a subject may still be processing one signal (or preparing its response) when the next arrives. Much of the substantial theory and data on this problem, i.e., detecting signals presented at irregular intervals (discussed in Chapter 5), represents Lute’s own collaborative work with David Green. Stimulus and response interactions (termed “sequential effects”) also arise in Identification Paradigms, usually studied in “serial RT” tasks that present each new choice stimulus as soon as (or shortly after) a subject responds to the previous stimulus. For a book of this length and complexity it is remarkably free of errors, typographic or other. There are two places, however, where the captions have been switched between figures, which might temporarily confuse an unwary reader. This occurs on pp. 18-19 (Fig. 1.6 and Fig. 1.7) and on pp. 160-161 (Fig. 4.21 and Fig. 4.22). I found no errors in the equations or formal derivations-other than those I committed while filling in steps that were uncomfortably long. This is a book that should be read by every experimental psychologist, surely by those interested in quantitative models or whose research involves RT measurement. It would form an ideal core for a graduate course or seminar, and was, in fact, developed out of a graduate seminar that Lute taught for several years. No other source even approaches the breadth of material that Lute has covered in this book, in its treatment of either RT theory or RT methods and data. Previously,
BOOK
REVIEW
477
the only sources other than the original individual articles have been a few specialized reviews and books, narrowly focused on particular experimental paradrgms or types of models. In view of the fact that Lute has written the only broadly conceived book on RT theory and measurement, it is particularly fortunate for us that he has done such a good job of it.
OF MATHEMATICAL
PSYCHOLOGY
32, 474477 (1988)
Book
Review
Response-Time Measurement: A Definitive Progress Report R. DUNCAN LUCE. ResponseTimes: Their Role in Inferring Elementary Mental Organization. New York: Oxford Univ. Press, 1986. Pp. xv + 562. $75.00. Reviewed
by RICHARD G. SWENSSON
R. DuncanLute was Alfred North Whitehead Professor of Psychology and now is Victor S. Thomas Professor of Psychology at Harvard University. He received his Ph.D. in mathematics in 1950 from the Massachusetts Institute of Technology, and remained at MIT as a member of the Research Laboratory for Electronics until 1953. Since that time he has held various academic positions, including a Benjamin Franklin Professorship in the Departmentof Psychology at the University of Pennsylvania, a Visiting Professorship of Social Science at the Institute for Advanced Study, Princeton, and Professor of Social Sciences at the University of California at Irvine. He is a member of the National Academy of Science and of the American Academy of Arts and Science, and he was president of the Psychometric Society, 1976-77, and of the Society for Mathematical Psychology, 1979-80. He has published numerous books including Games and decisions: Introduction and critical survey (with H. Raiffa, Wiley. New York, 1957), individual choice behavior: A theoretical analysis (Wiley, New York, 1959), and Foundations of measurement (with D. H. Krantz, P. Suppes, and A. Tversky, Academic Press, San Diego, Vol. I, 1971; Vols. II and III, in press). His current research interests include theoretical work on measurement structures, especially in the areas of utility and risk. The reviewer, Richard G. Swensson, is with the Department of Radiology, Harvard Medical School and Brigham and Women’s Hospital. He obtained his Ph.D. in experimental psychology at the University of Michigan in 1969 and has been on the staff of the Army Behavioral Science Research Laboratory, Washington, DC, and of Bell Telephone Laboratories, Holmdel, New Jersey. His current research interests involve signal detection theory and psychophysics, with applications to radiographic image analysis.
The subtitle of this book conveys Duncan Lute’s view that the goal of studying response time (RT) is to infer the basic organization of mental processes in perceptual and cognitive tasks. Lute believes that these underlying processes can be best understood by developing quantitative theory to describe their characteristics and interaction. Accordingly, his book focuses on formal, analytic models that can interpret and predict measurements of RT and response probability in experimental tasks. But Lute also respects the consensus of empirical data that theory must Requests for reprints should be sent to Richard G. Swensson, Department of Radiology, Harvard Medical School and Brigham and Women’s Hospital, 25 Shattuck St., Boston, MA 02115. 474 0022-2496/88 $3.00 Copyright ,CI 1988 by Academic Press, Inc. All rights of reproductmn m any form reserved.
BOOK
REVIEW
475
explain. The book reviews, and presents in some detail, a careful selection of the important quantitative experimental results in this large and complex field. In addition to a rigorous examination of existing models, and their predictive adequacy, there is considerable thoughtful discussion of the methods (both statistical and experimental) by which theory and data are related. What Lute modestly describes as a “progress report” is a book that systematically integrates present theory with the experimental methods and available data. It represents a definitive review of RT measurement in experimental Psychology. The book has been organized into three major sections that deal with experimental paradigms of increasing task complexity: Detection, Identification, and Matching and Search. In a Detection (e.g., “simple-RT”) Paradigm the subject makes a single response, usually as quickly as possible, to a single reaction signal. An Identification (e.g., “choice-RT”) Paradigm specifies separate responses for each of two or more reaction signals, usually directing the subject to respond both quickly and accurately. Matching and Search Paradigms represent “more cognitive” tasks that map several different signals into the specified responses (often only two). For example, the subject’s response may classify a given signal according to some prespecified mapping (Matching), or it may indicate whether or not any of several signals fall into a specified class (e.g., Visual Search). Despite its focus on RT models, this book can be understood and appreciated by readers with diverse mathematical backgrounds. Much of the material, including substantial discussions of experimental results and methods within each section, demands little beyond logarithms and elementary probability. The formal tools and concepts needed for the more theoretical material are developed, clearly and concisely, in Chapter 1. These are the ideas of probability and random variables used to characterize RT distributions (e.g., by hazard functions and as latency convolutions) and to derive the predictions of various RT models. Even sophistocated readers can profit from this conceptual review; others, if diligent, will find these tools suffjcient for all but a few of the formal derivations. The two largest sections are those on Detection and Identification paradigms, for which quantitative models of RT have been developed in most detail. Separate chapters in these two sections examine the basic empirical results and methods for simple-RT tasks (Chapter 2), for two-choice RT tasks (Chapter 6), and for multiple-alternative RT tasks (Chapter 10). Theoretical issues are the focus of Chapters 3-5 (Detection) and Chapters 7-9 (Identification), which develop the predictions of existing models and examine their adequacy. The section on Matching and Search Paradigms first discusses basic experimental results and methods for memory scanning, visual search and “samedifferent” tasks (Chapter 1 l), together with the models typically used to interpret such data. This is followed by a more mathematical discussion (Chapter 12) of the uniqueness and identifiability of the underlying structures assumed by these “cognitive” models. Lute identifies several reoccurring “themes,” which represent similar effects, methodological problems, and theoretical concerns in both detection and identification paradigms: One is the generally accepted presumption that a measured ao/32:4-9
476
BOOK
REVIEW
RT represents a sum of component latencies: the time consumed by some central “decision” process (the focus of most models) added to a “residual” latency, contributed by a series of peripheral (input and response) processes. Chapter 3 discusses the decomposition of RT into decision and residual-latency components. This is a major theoretical concern for models in detection paradigms, and a methodological problem for models of the decision process in identification paradigms. Another major theme is the pervasive phenomena of subject-controlled tradeoffs, which affect both RT and response probability. The speed-accuracy tradeoff, i.e., an inverse relation between the speed and accuracy of a subject’s responses, is a wellknown result in identification tasks. A similar tradeoff occurs in detection tasks; subjects may vary their “responsiveness,” with faster simple-RTs achieved at a cost of more anticipations or catch-trial responses. Such tradeoffs impose fundamental constraints on models of the decision processes, which must predict a functional relation between the decision’s latency and its “adequacy.” Although empirical tradeoff functions are difficult and tedious to estimate with sufficient precision, they can provide unique information about the structure of the underlying decision processes. Lute uses the predicted form of the speed-accuracy tradeoff function in Identification Paradigms as a major basis for his discussion and comparison of alternative models (Chapters 7-9). A third reoccurring theme is Lute’s discomfort with the rigid temporal structure that most experiments impose on the presentation of signals, i.e., time partitioned into individual trials, but which subjects never encounter outside the laboratory. Experiments that present signals at random intervals in time create the possibility of interactions between successive signals (and responses), however, since a subject may still be processing one signal (or preparing its response) when the next arrives. Much of the substantial theory and data on this problem, i.e., detecting signals presented at irregular intervals (discussed in Chapter 5), represents Lute’s own collaborative work with David Green. Stimulus and response interactions (termed “sequential effects”) also arise in Identification Paradigms, usually studied in “serial RT” tasks that present each new choice stimulus as soon as (or shortly after) a subject responds to the previous stimulus. For a book of this length and complexity it is remarkably free of errors, typographic or other. There are two places, however, where the captions have been switched between figures, which might temporarily confuse an unwary reader. This occurs on pp. 18-19 (Fig. 1.6 and Fig. 1.7) and on pp. 160-161 (Fig. 4.21 and Fig. 4.22). I found no errors in the equations or formal derivations-other than those I committed while filling in steps that were uncomfortably long. This is a book that should be read by every experimental psychologist, surely by those interested in quantitative models or whose research involves RT measurement. It would form an ideal core for a graduate course or seminar, and was, in fact, developed out of a graduate seminar that Lute taught for several years. No other source even approaches the breadth of material that Lute has covered in this book, in its treatment of either RT theory or RT methods and data. Previously,
BOOK
REVIEW
477
the only sources other than the original individual articles have been a few specialized reviews and books, narrowly focused on particular experimental paradrgms or types of models. In view of the fact that Lute has written the only broadly conceived book on RT theory and measurement, it is particularly fortunate for us that he has done such a good job of it.