Part CONCEPTS, THEORY, AND METHODS IN THE PSYCHOLOGY OF AGING 1 | 48 the seventh-grade textbook. By 1971 the same concept was taught to third graders, and by 1991 a first-grade textbook included a simplified version of the concept. CHANGES OF OCCUPATIONAL STATUS AND WORK COMPLEXITY Major historical changes in the US. workforce have occurred across cohorts (cf. Schaie & Schooler, 1998 ). Currently 20% of workers are in professional occupations, compared to 7% in 1950, while farmers have decreased from 10% into. The median age of retirement is now 62 years with only 18% of men 65 working, compared to 46% in 1950. Women ’ s work participation has increased with 52% of women aged 55 to 64 working compared to 27% in 1950 ( Blau & Duncan, 1967; Farr & Schwall, 2008 ). Occupational experience is related to maintenance of cognitive abilities at older ages ( Owens, 1966 ).
Avolio and Waldman (1990) reported that occupational status moderated the relationship between age and cognitive ability with a negative relationship for unskilled workers and no relationship for skilled workers. Salthouse (1990 ) reported that architects preserved higher levels of spatial ability later in the lifespan when compared with non-architects of similar ages. Historical shifts in work organization have resulted in fewer hierarchical levels and increased worker self- direction and responsibility fora broader range of tasks. As a result, job complexity has increased. Job conditions involving self-directed, substantively complex work are associated with increased intellectual flexibility and self-direction ( Kohn & Schooler, 1983;
Schooler, 1990, 1998 ). Findings indicate that the reciprocal relation between substantively complex work and cognition are even stronger in older men than was found in younger men ( Schooler & Caplan, 2008; Schooler et al., 2004 ). Schooler ’ s work also suggested age/cohort differences in work complexity older workers, on average, were found to do less substantively complex work. Fora theoretical discussion of cognitive plasticity see Willis et alb CHANGES IN HEALTHCARE,