The theory presented by Grice, Nullmeyer, and Spiker (1977) has been applied successfully to experiments with three levels of auditory similarity in choice reaction time. A defect in the original statement of the relation between theoretical probabilities and response probability is corrected. Similarity affects both positive associative strength and associative inhibition. The short-latency process of associative inhibition is especially sensitive to increasing levels of similarity. Descriptions of the speed-accuracy tradeoff as it depends upon stimulus similarity are presented. The forms of stimulus generalization gradients are shown to depend upon response latency. Common sets of theoretical functions described both group and individual subject latency distributions. As before, three individual difference variables are identified as mean criterion level, amount of criterion variability, and inhibitory ability. Multiple regression analysis of these three variables and error rate reveals interesting and interpretable features of information processing dynamics. One of these features is that the amount of criterion variability may be more important in determining error rate than the mean level of the criterion. Also included are comments on a critique by Link (1979) and a discussion of the relation between this approach and more formal deductive models. © 1979 Psychonomic Society, Inc.
