Does variability increase with age? An archival study of cognitive measures

It is often asserted that older people are more variable than younger people; however, the published data do not always support this statement. To examine directly the applicability of the assertion, measures of reaction time (RT), memory, and intelligence from studies published in Psychology and Aging and the Journal of Gerontology from 1986 to 1990 were examined. The coefficients of variability calculated from data published in studies in which a group of younger people was compared with a group of older people indicated that variability was greater among older participants on measures of RT, memory, and fluid intelligence but not crystallized intelligence. Further examination of data bearing on relative variability is indicated.