Review of Arthur R. Jensen (2006)--Clocking the mind: Mental chronometry and individual differences.

Abstract

Mental chronometry, as Arthur Jensen stresses, is study of reaction time (RT) in its various guises, contexts, and applications. As with respect to much of experimental psychology (cognitive and other), there is a venerable past here lying in background, providing a wide-ranging context in which to embed our current (that is, our 40-odd year) preoccupation with as a primary dependent measure in cognitive psychology. This recent book, Clocking Mind: Mental Chronometry and Individual Differences (published by Elsevier), weds both differential psychology's concern with measurement of individual differences in (e.g., Austin, Deary, Gibson, McGregor, & Dent, 1998) and experimental psychology's concern with the effects of manipulating various external conditions on variation in measurements of RT (p. 1). The reader of this journal will most probably be more familiar with latter use of in literature, especially when embedded within such familiar experimental tasks as those tapping both Garner and Stroop effects (Pansky & Algom, 1999). If this be case, then one might well be wondering why such a book is needed. After all, do we not all know how to measure and to use this profitably in our research? In answer, I would like to state that it is always instructive to read a book by a master of field. Arthur Jensen is, of course, well known for his contributions to study of intelligence, including (but not limited to) use of in this domain. The book comprises 14 chapters (272 pages), discussing history, terminology, and paradigms (first three chapters), continuing with measurement, developmental issues, cognitive aging and genetics (next four), focussing on individual differences in five subsequent chapters (dealing with psychometrics, correlating Chronometrie and psychometric measures, inspection time, and IQ, and relation of to other variables), and ending with two chapters discussing clinical and medical uses of and a plea for standardizing chronometry. To my mind, first half of book (until page 135) will be of use to a general audience, who have an interest in use of in research, while not necessarily being concerned with issue of individual differences. This notwithstanding, it is from vantage of study of individual differences (including psychometric considerations) that Jensen contributes some compelling thoughts regarding RT, some of which will certainly challenge experimental psychologist. I will elaborate on eight of these points - choosing five from first half and three from second half, but intermeshed below. These points are as follows, and discussed in this order: 1) standard measurement of RT, 2) use of additive factors in analyzing RT, 3) psychometric considerations for RT, 4) Brinley plot, mapping older (aging) onto younger RT, 5) use of regression parameters in chronometry, 6) ensuring independence of measures in multivariate analyses, 7) speed-accuracy trade-off for RT, and 8) brain-behaviour relationships and RT. I will exploit this platform to engage in debate with author. To begin with, even though this insight appears at end of book, standard practice of using a computer keyboard to measure comes under attack (Point 1): The four cursor keys are most frequently used. Because these keys are on right-hand side of keyboard, they possibly favor right-handed subjects... Subjects also find it distracting or confusing to have whole complex keyboard exposed when only a few keys are needed for particular task... Many obvious disadvantages of using a computer keyboard as response console make it least desirable choice for minimizing irrelevant and unwanted sources of variance in Chronometrie measurements, (p. 240) As Jensen indicates, experimental psychologists may well have introduced a source of systematic error into computerized lab. …