How does the strength of the relationships between cognitive abilities evolve over the life span for low-IQ vs high-IQ adults?

The present study was designed to examine how the correlations between cognitive abilities evolve during adulthood. Data from 1104 participants on the French version of the Wechsler Adult Intelligence Scale-Third Edition were analyzed. The entire sample was divided into four age groups (16–24 years; 25–44 years; 45–69 years and 70–89 years), which were themselves split into two IQ-levels using the mean standard score on Vocabulary and Block Design. For every age group, the mean correlation between subtest scores of low-IQ participants was higher than that of high-IQ participants. There was also no interaction between age and IQ for the strength of subtest relationships. Indeed, the effect sizes of correlation differences between low- and high-IQ participants appeared to be relatively constant across age. A general developmental schema of how the strength of correlations between cognitive abilities of low- and high-IQ individuals evolves during the entire life span is sketched in the discussion.