On the problem of detecting effects of lifestyle on cognitive change in adulthood: Reply to Pushkar et al. (1999).

The authors respond to issues raised about data from the Victoria Longitudinal Study and further explain concerns regarding evidence for the engagement hypothesis. Discussion focuses on the use of social stratification variables such as occupational prestige and educational attainment as measures of an engaged lifestyle. It is argued that (a) tests of the hypothesis should focus on the relationship of behavior and activities thought to be proximal beneficial influences on adult cognitive development: (b) persuasive evidence for engagement effects from existing data require demonstration of effects of intellectual activities that are statistically independent of associations of social status with intellectual and cognitive development; and (c) currently available longitudinal data do not provide definitive evidence regarding the benefits of an engaged lifestyle on cognitive change.