Three measures of slowing of behavior were analyzed to describe age- related differences as well as age changes: reaction time, movement time, and nerve conduction velocity. Age-related changes in reaction time were not as robust as the cross-sectional age differences suggesting that factors other than age are responsible for part of the age declines observed. Reciprocal manual movement speed declines relatively more rapidly with greater task difficulty in older age. Although cautiously reported, nerve conduction velocity decreased with older age with age difference becoming apparent around age fifty.
