The continuing effects of substantively complex work on the intellectual functioning of older workers.

Using a nationally representative sample of employed men and women in this longitudinal study, the authors extended for another 20 years findings based on 1964 and 1974 data (Kohn & Schooler, 1983) that substantively complex work improves intellectual functioning. This study provides evidence that intellectual functioning and substantive complexity of work continue to reciprocally affect each other. In addition, it shows that the intellectual flexibility measure used earlier (Kohn & Schooler, 1978, 1983) is highly correlated with more standard measures of intellectual functioning. Most importantly, it shows that, although substantively complex work significantly increased the level of intellectual functioning of both the younger and older halves of the sample, the effect is significantly greater among the older workers.