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This study examined the fluid-crystallized distinction of cognitive abilities in African Americans. We analyzed the factorial invariance of a battery of cognitive ability measures in a sample of 197 community-dwelling African American elders. Specifically, factorial invariance was tested in groups of African American elders differing in age (50-61 years, 62-79 years) and education (low, high). Using a partial invariance approach, if non-invariance was found between two groups, we explored the specific model parameters that contributed to the overall lack of invariance. The results indicated that the factor structure was confirmed in the sample as a whole. Evidence of strict invariance was found between age groups. However, a lack of invariance of specific factor loadings, intercepts, and uniqueness terms was found between education groups. The importance of highlighting idiosyncrasies in cognitive performance among African Americans is shown using a within group variation approach. [ABSTRACT FROM AUTHOR]

The structure and organization of cognitive abilities has been examined across the life span. The current analysis had three specific aims: (1) test the factor structure of a broad cognitive ability battery across three age groups; (2) examine differences in the pattern of factor covariation across age groups; and (3) examine the pattern of factor mean differences across age groups. A sample of 512 older African Americans (mean age = 66.6 years, 25.4% male) from the Baltimore Study of Black Aging was administered a battery of cognitive tests assessing the domains of perceptual speed, verbal memory, inductive reasoning, vocabulary, and working memory. Factor models were estimated separately in middle-age adults (50-59 years, n = 107), young-old adults (60-69 years, n = 198), and old-old adults (70-79 years, n = 207). There was loading invariance across the three age groups that suggests that the selected tests measured cognition similarly across age. There was no evidence of dedifferentiation across increasingly older age groups. Factor mean differences were observed with the middle-age group having significantly higher factor means than the young-old and old-old groups; however, there was only one factor mean difference between the young-old and the old-old groups. The results suggest that a pattern of dedifferentiation of cognitive abilities does not exist within this sample of older African Americans and that the 60-69 year age range may be a critical period for cognitive decline in this population. [ABSTRACT FROM AUTHOR]