The Intercohort Decline in Verbal Ability: Does It Exist?

Abstract

Has there been a long-term intercohort decline in verbal ability beginning in the early part of this century? Recent analyses by Alwin and Glenn using data from the General Social Survey (GSS) strongly support such a trend. This decline, however, is not consistent with a substantial literature on adult cognitive development. We argue that Alwin's and Glenn's analyses confuse cohort effects with aging effects, apparently because of (1) a reliance on outdated assumptions, or “side information,” regarding the relationship between age and verbal ability; (2) the treatment of the relationship between age and verbal ability as linear rather than curvilinear; and (3) the high degree of collinearity between age and cohort in the GSS data. The observed trend in the GSS data appears to be explained best by a positive relationship between age and verbal ability rather than by a decline in ability across cohorts. Because the GSS data involve a set of national probability samples conducted over a 22–year period, our analyses complement and strengthen the credibility of the literature on adult cognitive development.