SHOULD WE TAKE THE SHAPE OF REACTION-TIME DISTRIBUTIONS INTO ACCOUNT WHEN STUDYING THE RELATIONSHIP BETWEEN RT AND PSYCHOMETRIC INTELLIGENCE

The negative correlation between psychometric intelligence and variability of reaction time (RT) in elementary cognitive tasks (ECTs) is now well established. However, there has been relatively little research aimed at describing distributions of RT trials other than with mean, median and standard deviation. The present study was designed to examine the relationship between measured intelligence and parameters yielded by exGaussian analysis of RT distributions. Fifty two subjects were administered a computerized discrimination task and five intelligence tests. Data collected indicated that the skewness of RT was more correlated with psychometric intelligence than intraindividual variability in RT was. In addition, and though the exGaussian analysis provided a good description of RT distributions, the results showed that the parameters of the analysis did not correlate significantly with measured intelligence.