Gray hair, remembering, activity levels—Why do adults differ so much on these and other things? This question requires us to understand the basic forces that shape us. Developmentalists typically consider four interactive forces (shown in Figure 1.8):

• Biological forces include all genetic and health – related factors that affect development. Examples of biological forces include menopause, facial wrinkling, and changes in the major organ systems.

• Psychological forces include all internal perceptual, cognitive, emotional, and personality factors that affect development. Collectively, psychological forces provide the characteristics we notice about people that make them individuals.

• Sociocultural forces include interpersonal, societal, cultural, and ethnic factors that affect development. Sociocultural forces provide the overall contexts in which we develop.


Figure 1.8 Each person is the product of the interaction of biological, psychological, sociocultural, and life-cycle forces.

• Life-cycle forces reflect differences in how the same event or combination of biological, psychological, and sociocultural forces affects people at different points in their lives. Life-cycle forces provide the context for the developmental differences of interest in adult development and aging.

One useful way to organize the biological, psychologi­cal, and sociocultural forces on human development is with the biopsychosocial framework. Together with life-cycle forces, the biopsychosocial frame­work provides a complete overview of the shapers of human development. Each of us is a product of a

unique combination of these forces. Even identical

twins growing up in the same family eventually have their own unique friends, partners, occupations, and so on. To see why all these forces are impor­tant, imagine that we want to know how people feel about forgetting. We would need to consider several biological factors, such as whether the forgetting was caused by an underlying disease. We would want to know about such psychological factors as what the person’s memory ability has been through­out his or her life and about his or her beliefs about what happens to memory with increasing age. We would need to know about sociocultural factors, such as the influence of social stereotypes about forgetting. Finally, we would need to know about the age of the person when a forgetting experience occurs. Focusing on only one (or even two or three) of the forces would provide an incomplete view of

14 CHAPTER 1 how the person feels. The biopsychosocial frame­work, along with life-cycle forces, will provide a way to understand all the developmental outcomes you will encounter in this text.