Cognitive Development Across Adulthood

1. Cognitive Development AcrossAdulthood Lecture 11/29/04

2. Defining Adult Intelligence • Robert Sternberg’s triarchic theory distinguishes between analytic, practical, & creative intelligence. • Further, it is assumed that different environments would necessitate different responses. The nature of intelligence would change with age if the environments to which people are exposed typically change with age as well.

3. Robert Sternberg’s: Triarchic Theory • Practical problems tend to: • require problem recognition & formulation • be poorly defined • require additional information • have alternative solutions • be closely tied to & require previous everyday experience • require personal interest & involvement • Analytic problems tend to: • be formulated by other people • be clearly defined • come with all the information needed to solve them • have a single correct answer that can be reached in only one way • be presented out of context with ordinary experience • have little intrinsic interest

4. Life-Span Cognitive Development • Decrementalist View: there is universal, inevitable, & pervasive decline. • Continued-potential View: development is lifelong & plastic-modifiable. • Investigators searching for the specific factors that influence the direction, rate, timing & variability of age-related cognitive change.

5. Schaie’s Seattle Longitudinal Study1956 to present • Began as doctoral dissertation at the University of Washington in 1956. • 5,000 subjects • Seven-year intervals • Contributed significantly to our understanding of methodological issues (i.e., internal and external validity issues) in developmental studies. • In general, longitudinal age changes are less pronounced than cross-sectional data for most variables.

6. Schaie’s Seattle Longitudinal Study1956 to present II • Modest cognitive decline begins in the early 60s • Marked decline does not occur until the 80s. • Number ability begins to decline in the 50s. • Cumulative decline is larger for men than women on verbal meaning and inductive reasoning. • Practical intelligence peaks by age 60 and does not decline prior to the 80s.

7. Schaie’s Seattle Longitudinal Study1956 to present III • Sampling equivalence study showed specific age-cohort by test differences, but no general problematic issues for equivalence. • Studies of participant attrition show effects across samples entering at different points from .3SD to .6SD. Although they decrease over test occasions, they remain statistically significant. • Subject attrition may result in the overestimation of rates of cognitive aging in longitudinal studies.

8. Schaie’s Seattle Longitudinal Study1956 to present IV • Structural equivalence / invariance is maintained across the entire age range sampled. • Stability of individual differences within cohorts is greater than differences across cohorts. • Factor regressions for young adults and for the very old may require differential weighting in age-comparative studies. • Gender equivalence in factor structure through middle adulthood, but loadings on latent constructs vary by gender in old age.

9. Schaie’s Seattle Longitudinal Study1956 to present V • 28-year longitudinal data show significant decrements by age 67 for: • Number • Inductive reasoning • Word fluency • 28-year longitudinal data show significant decrements by age 74 for: • Verbal meaning • Spatial orientation • Modest, average decline by age 74, steep by age 81.

10. Victoria Longitudinal Study (VLS)Definitions • Intra-individual change: relatively slow and enduring. • Intra-individual variability: inconsistency, or change that is relatively rapid and transient. • Differentiation and dedifferentiation of abilities.

11. VLS II • Early results indicate that inconsistency is substantial and related to impaired cognitive-aging. • Li et al (2001) found that, among individuals aged 64 to 86, variability in sensorimotor and one memory variable was positively associated with age. • Stable and constant individual differences are observed in inconsistency, and this is related to performance levels.

12. VLS III • Greater inconsistency in RT is associated with lower levels of “g”. • Hultsch et al (2002) found that greater inconsistency was associated with poorer performance on perceptual speed, working memory, episodic memory, and crystallized abilities. • Measures of inconsistency and levels of performance are independent predictors of cognitive functioning.

13. VLS IV • Young old n = 135 aged 55 to 64 years • Mid-old n = 225 aged 65 to 74 years • Old-old n = 86 aged 75 to 89 years

14. Victoria Longitudinal Study Findings • Greater inconsistency found for older adults even when controlling for differences in response speed. • Associations between inconsistency at baseline and 6-year longitudinal change. • Longitudinal change in inconsistency. • Intraindividual covariation between 6-year change in inconsistency and 6-year change in level of cognitive functioning.

15. VLS Cross-sectional Findings II • On paper-and-pencil cognitive tasks, no age differences were observed on vocabulary. • On paper-and-pencil cognitive tasks, young-old outperformed mid-old who outperformed old-old groups on identical pictures, computation span, & letter series. • On word recall and story recall, the old-old performed significantly worse than young-old or mid-old groups. • There were significant declines across the 6-year period for all measures, increasing for older age groups.

16. VLS Longitudinal Findings III • Average inconsistency tended to remain stable or decrease for young-old and mid-old groups, but increased for the old-old group. • Performance variability serves as a marker of cognitive aging: • Particularly for those over age 75, inconsistency shows marked longitudinal increases that may reflect age-related CNS changes. • As much as 6.3% of within-person variance in cognitive change was accounted for by 6-year change in inconsistency.

17. VLS Longitudinal Findings IV • BUT • No significant age-group differences were found in patterns of covariation between 6-year change in cognition and inconsistency, suggesting that patterns are similar across age groups. • Observed covariations were greater for episodic memory measures than for more basic information processing measures.

18. Questions • What are the critical mental activities that facilitate adaptation? • How can they be measured? • Do they change systematically with age?