Intelligence and speed of information processing: Further results and questions on Hick's paradigm and beyond

In the last 10 years, there have been an increasing number of results indicating a relation between parameters of processing speed in elementary cognitive tasks as in the Hick paradigm and basic aspects of psychometric intelligence (usually “general intelligence” or g). Unfortunately the pattern of findings is somewhat inconsistent and there is little theoretical basis for explaining and integrating the various results. Relations of reaction time (RT)-parameters with other aspects of intelligence (e.g. structural components) have largely been neglected. To replicate main results concerning the RT x intelligence relations and to analyze these relations in a broader context of intelligence variables, the Hick paradigm, the Berlin Model of Intelligence Structure (BIS), and Raven's Advanced Progressive Matrices (APM) were employed. The intelligence tests were administered on the first day to 73 subjects, most of them university students, and the Hick paradigm was administered twice on the second day of the study. On a basic level of analysis two of three “classical” assumptions on the Hick paradigm are replicated; significant negative correlations between general intelligence (APM, BIS-AI) on the one hand and intercept and intraindividual variances in RT on the other hand. In contradiction with the “classical” assumptions, the negative correlation between general intelligence and the slope parameter could not be replicated. Surprisingly, RT-medians and -variances per bit level proved to have as least as much prognostic power as the classical Hick parameters directly based on Hick's law (slope and intercept). Significant correlations between RT-parameters and BIS-components, especially processing speed (B), should induce more thorough investigation on the intelligence side of the RT x intelligence relation. The results indicate again that main findings pertaining to the Hick paradigm represent relatively stable relations. But the findings are not consistent and partially give reasons for doubts about some central until now available positive findings. A substantiating theory for explaining and integrating positive results, anomalies and prevailing ad-hoc assumptions and for integrating them into broader theories of intelligence meanwhile seems overdue.