[2] Schaie spent much of his career studying psychological development from young adulthood to old age.
[3] In 1986 he was a]ointed Evan Pugh Professor of Human Development and Psychology at Pennsylvania State University.
His research concerned developmental changes in adult intelligence, the impact of cognitive behavior in midlife and the integrity of brain structures in old age, and early detection of risk for dementia.
[3] Schaie also studied developmental research methodology in addition to the applications of the age-cohort-period model to psychology.
Schaie was the author or editor of 60 books and 300 journal articles and chapters on the psychology of aging.