Individual differences in information-processing rate and amount: Implications for group differences in response latency

Research on group differences in response latency often has as its goal the detection of Group x Treatment interactions. However, accumulating evidenc e suggests that response latencies for different groups are often linearly related, leading to an increased likelihood of finding spurious overadditiv e interactions in which the slower group produces a larger treatment effect . The authors propose a rate-amount model that predicts linear relationship s between individuals and that includes global processing parameters based on large-scale group differences in information processing. These global pr ocessing parameters may be used to linearly transform response latencies fr om different individuals to a common information-processing scale so that s mall-scale group differences in information processing may be isolated. The authors recommend linear regression and z-score transformations that may b e used to augment traditional analyses of raw response latencies.