To estimate Flynn effects (FEs) on forms of declarative memory (episodic, semantic) and visuospatial ability (Block Design) time-sequential analyses of data for Swedish adult samples (35-80 years) assessed on either of four occasions (1989, 1994, 1999, 2004; n = 2995) were conducted. The results demonstrated cognitive gains across occasions, regardless of age, with no evidence of narrowing gender gaps. Across the entire range of birth cohorts (1909-1969) the estimated gain approached 1 SD unit. Over most cohorts the gains were largest for semantic memory, with a tendency of decelerating gains on the memory factors, but not on Block Design, across more recent cohorts (1954-1969). Together, differences in education, body height, and sibsize predicted virtually all (greater than 94%) of the time-related differences in cognitive performance. Whereas education emerged as the main factor, the need to consider changes multiple factors to account for FEs is underscored. Their relative influence likely depends on which constellations of ability factors and stages in ontogenetic and societal development are considered.