The Effect of Stimulus-Response Compatibility on the Association of Fluid Intelligence and Working Memory with Choice Reaction Times

Abstract

It is a well-replicated finding that reaction time is correlated with performance in intelligence tests. According to the binding hypothesis of working memory capacity, the ability to establish bindings between elements and to integrate them into new structural representations is the source of the common variance between different cognitive tasks, including fluid intelligence and working memory. The goal of this study was to examine the effects of stimulus-response compatibility on the association between reaction time, fluid intelligence, and working memory. Based on the binding hypothesis, we expected that correlations between reaction time and fluid intelligence would be larger for arbitrary than for compatible stimulus-response mappings. We report data from two studies (Study 1: n = 135, mean age = 18 years; Study 2: n = 153, mean age = 17 years). We used choice reaction time tasks with compatible and arbitrary mappings as well as indicators of fluid intelligence and working memory (Study 1) and fluid and crystallized intelligence (Study 2). In both studies, we established a measurement model that included a factor reflecting general reaction time, and a nested factor reflecting the cost of establishing and maintaining arbitrary stimulus-response bindings. The results of Study 1 supported the hypothesis that the ability to uphold arbitrary bindings is correlated with working memory, but it was not correlated with fluid intelligence. In Study 2, the correlations between the binding factor and fluid and crystallized intelligence were again not significantly different from 0. We discuss possible reasons for these findings.