Part CONCEPTS, THEORY, AND METHODS IN THE PSYCHOLOGY OF AGING 1 | 42 aging, beginning with a volume on social structures and psychological processes ( Schaie & Schooler, 1989 ) and ending with a volume on social structure and aging individuals ( Schaie & Abeles, 2008 ). In trying to explicate my general developmental model I also began to specify broader substantive meaning for cohort beyond simply defining it as a common range of years of birth or defining period as the time of the measurement event (cf. Schaie, 1984, 1986, a ). Spurred by the work of the New Zealand political scientist Joseph Flynn (1984, 1987, 1999; Dickens & Flynn, 2001) who rediscovered the cohort effects inhuman abilities first introduced into sociology by Norman Ryder (1965) and into psychology by this author (1965), I began to think more seriously about the importance of historical influences upon behavior and aging. This interest increased even further during my collaboration with Glen Elder in organizing a conference on the historical influences on lives and aging ( Schaie & Elder, 2005 ). Since my aging research has largely focused on the adult lifespan trajectory of cognitive abilities, I decided to become more focused also in my thinking about historical influences on cognitive abilities as my dependent variables. I therefore began to identify the various historical changes occurring over the past century that might reasonably be sources of major impact ( Schaie, ab, b Schaie & Achenbaum, 1993; Schaie et al., 2005; Willis & Schaie, a ).
In this chapter, I will first marshal some theoretical arguments on why one should pay attention to historical influences in studying the aging process of various psychological constructs as individuals develop from young adulthood to old age to the end of their lives, and I will layout some of the principal concepts that require attention when studying such historical influences.
I will then examine historical changes in some of the major societal structures that I judge to be particularly prominent in influencing and constraining adult psychological development. The most prominent of these structures is the influence of educational attainment and changes in access to educational opportunities (such as caused by the GI bill, cf. Laub & Sampson, 2005 ). Second, I will examine the influence of changes in occupational structure caused by the shift from an agricultural and manufacturing economy to one that is highly technologically and service-ori- ented. Third, I will consider changes in healthcare and lifestyles that favorably impact level and change in optimal psychological functioning or compensate for declines that were common in earlier historical periods (cf. Leventhal et al., 2008 ). Fourth, I will discuss the influence of historical changes in immigration patterns as they affect the composition of the adult population and hence modify patterns of psychological aging in a given society (cf. Rumbaut, 2005 ). Fifth, I will briefly mention some other social interventions that have influenced the aging of psychological processes by major social interventions in the United States designed to reduce poverty in various specially targeted population segments (cf. Huston et al., 2005 ). Finally , I will summarize the effects of changes in the above historical influences and how they affect the psychological characteristics and rate of change in old age of the elderly and then engage in some modest speculation about how these trends might develop over the next decade or two.