To examine the number of subjective age categories in the post-high school portion of the American lifecycle, adult respondents sorted cards describing people in terms of major life events and classified them according to age. A nonlinear decrease in the number of age distinctions occurred in the late portion of middle age (46-65 years). (Author)

Matrix tasks to assess multiple classifications and multiple seriation skills were administered to 160 children (40 Ss each from preschool, kindergarten, first and second grade levels). Each child received six matrix subtasks (reproduction and transportation of cross classification I, double seriation, and cross classification II) in one of six…