Response speed on aptitude tests as an index of intellectual performance: A developmental perspective

The development of mental speed has been studied extensively in recent research, but its consequences on individual differences in intelligence are still largely unknown. We examine this issue here, with an index of mental speed measured from computerized aptitude tests items. This index of mental speed rallies three methodological controls (separate measures of speed and level of ability, control for the correctness of the response and for the itemʹs difficulty), which permit one to go beyond the confusion that has reigned in psychometric studies of mental speed and to bypass most of the criticisms that have been addressed recently to elementary cognitive tasks. Our results show an increase in response speed from the age of 9 to 11 years and a strong correlation between speed and mental age. We also observed an increase, from the ages of 9 to 11, in the correlation between speed and IQ. In conclusion, we explore the hypothesis of a transformation, with age, of the combination of processes that are involved in performance. This transformation would be comparable to automatization.