Looks at how chronological age, relationships, life transitions, and social change shape people"s lives from birth to death (study of the relationship between time and human behavior) The family is a micro social group in a macro social context. Studied those who were apart of the great depression and how it affected them after the fact. Social development differs through time because of how social institutions change and vice versa. Group of people who share a common characteristic. Birth cohort: baby boomers, gen-x (born in same time period/generation) Change in status or role that distinctly differs from the previous status or role. Refers to the happening not the transition of the outcome. People usually experience about 3 in their life. Behavior and decisions do not occur in a vacuum. Same historical events may affect different cohorts in different ways. Age norms change with time, place, and culture.