lems—using correct or incorrect, taught or invented strategies—by such formal analysis. As the simple addition example in Box 3–4 illustrates, hypothesized models of underlying cognitive activities lead researchers to collect rich data sets that can be used to test hypotheses about both the process and progress of students’ learning. Such models can also provide a foundation for interpreting evidence derived using other data gathering and analysis techniques. Some of the most useful techniques, including reaction-time studies, computational modeling and simulations, analysis of protocols, microgenetic analysis, and ethnographic analysis, are described below.
As illustrated for the case of simple addition problems, one method of evaluating cognitive processes is to measure and analyze the amount of time people spend on various phases or components of a given task. Data from these analyses can be highly informative when interpreted according to a model of cognitive processes. With an appropriately chosen set of problems, researchers can determine which of several potential strategies or approaches the problem solver is using. This general approach has been used for a wide variety of tasks, varying in complexity from simple addition and subtraction problems for children (e.g., Siegler, 1998) to complex multimove puzzles (Klahr and Robinson, 1981).
MacLeod, Hunt, and Mathews (1978), for example, used reaction-time profiles to determine whether people used imagery to solve simple verbally presented problems. More recently, Hunt, Streissguth, Kerr, and Olson (1995) used a combined measure of reaction time and accuracy to show that children whose mothers had used alcohol during pregnancy displayed tendencies to be impulsive in problem-solving behavior. This observation, which took less than an hour to make, was consistent with observations made by classroom teachers over a period of months. (It may be noted that the children were 14 years old at the time of testing, so the method may have isolated the effect of a drug taken 15 years prior to testing.)
Eye-movement tracking, a specialized technique for studying reaction times and other key behaviors, has received virtually no attention in the assessment literature. By using what is now relatively inexpensive equipment capable of detecting the direction of a person’s gaze while he or she is engaged in a task, psychologists can gather data about the sequence and duration of eye fixations. This information can then be combined with the results of cognitive analysis to infer—quite precisely, in many cases—which of several strategies is being used. Such analyses can yield insights into differences between experts and novices in a range of domains, from playing chess to operating a modern airliner. This approach provides a “window on the mind” that complements and augments other, more traditional ways