According to Schaie, in later life the need to acquire new skills or to monitor the effects of decisions decreases. What happens is reintegration of intellectual abilities into a simpler form. There is an emphasis on remaining intellectually involved in meaningful situations. Intellectual endeavors are influenced by motivational and attitudinal considerations more than at any other time. Expertise Adults build up a wealth of knowledge about different ways to solve problems or make decisions that allow us to get around steps needed by younger adults.
Older people are sometimes able to compensate for declines in basic intellectual abilities.
Expert performance peaks in middle age and drops off slightly after that. This page talks about a study that was done to see why older adults continue to be successful without having 40 percent of intellectual ability of a 25 year old. It talks about practical intelligence, which is not measured with IQ tests. This page gives a definition of fluid intelligence and how it relates to the older population. This page gives a definition of crystallized intelligence and talks about the ongoing debate of whether or not intelligence declines with aging.