PartCONCEPTS, THEORY, AND METHODS IN THE PSYCHOLOGY OF AGING 1 |46 In contrast, cross-sectional reports on college admission tests indicate negative cohort trends for certain birth cohorts of young adults ( Astin & Henson, 1977; Wilson & Gove, 1999 ). Likewise, Alwin (1991 ; Alwin & McCammon, 2001 ), and Glenn (1994) reported negative cohort trends in verbal ability. To examine cohort-related shifts in the domains of intelligence impacted by culture, an extensive database of multiple cohorts studied over the same developmental ages is needed, such as is present in the Seattle Longitudinal Study (SLS; Schaie, a ). Studies, such as Flynn ’ s, highlight some of the serious limitations in prior cohort studies of cognition — focusing only on level , rather than developmental change in cognitive functioning, on a limited number of cohorts, over a single age period, and with no consideration of cohort- related differences in trajectory patterns (cf. Schaie, b Schaie et al., 2005; Schaie & Zanjani, 2006 ).