Growth curve analysis of ability means and variances in measures of fluid intelligence of older adults

This article is concerned with an application of growth curve analysis to modeling test performance changes demonstrated by older adults following cognitive training or based on experience with repeatedly presented fluid intelligence measures. Group differences and invariance in change over time in ability means and indices of interindividual differences at the ability level in a 2‐group cognitive intervention study (Baltes, Dittmann‐Kohli, & Kliegl, 1986) are examined using 3 latent curve analysis (Meredith & Tisak, 1990) models. The results indicate (a) group equivalence in the pattern of temporal development of ability variances and (b) training effects in the experimental group that are stronger than the practice/experience effects in the control group, whereby both types of effects are maintained over the 6‐month testing period. The findings provide further suggestive evidence for plasticity in fluid intelligence of elderly adults (cf. Baltes et al., 1986; Raykov, 1995, 1996).