Middle adulthood spans from about ages 40 to 65. During this period, individuals experience physical decline but also reach their peak career satisfaction and responsibility. They make important choices about generativity as physical signs of aging emerge. Cognitively, crystallized intelligence increases while fluid intelligence decreases. Erikson's theory of generativity vs. stagnation applies as adults aim to leave a legacy. Personality remains stable through traits like the big five. Family relationships, including with partners, children, parents and siblings, are most important sources of support. The "sandwich generation" concept of caring for young and old is largely a myth for most.