The biggest declines among men younger than age 65 did not occur until after 1970. As we shall see, this pattern of labor market withdrawal is consistent with the view that the introduction and liberalization of social security was an important factor in pushing down the rates. Because expected male life spans increased about 0.6 year a decacle during a period in which the retirement age dropped 1.4 years a decade, the amount of the male life span devoted to retirement climbed about 2 years a decade. Retirement now represents a substantial part of a typical worker's life. For many if not most workers, retirement will last longer than the period from birth until full-time entry into the job market.
Some evidence suggests that behavior is slow to change in the face of changing financial incentives.
It took a number of years after the intro- duction of early social security pensions before retirement at age 62 became common. The financial incentives that eventually induced men to retire at age 62 were presumably present from the first day early pensions became available in 1961. It was only in the late 1960s, however, that a sharp fall- off in labor force participation at age 62 became noticeable. By the late 1 970s, the fall-off in participation was greater at age 62 than at age 65. This evidence may suggest either that workers are slow to recognize the financial implications of a complicated innovation or that their preferences are formed, in part, by important changes in the financial- incentives facing them.