How much does education improve intelligence? A meta-analysis

Intelligence test scores and educational duration are positively correlated. This correlation could be interpreted in two ways: Students with greater propensity for intelligence go on to complete more education, or a longer education increases intelligence. We meta-analyzed three categories of quasiexperimental studies of educational effects on intelligence: those estimating education-intelligence associations after controlling for earlier intelligence, those using compulsory schooling policy changes as instrumental variables, and those using regression-discontinuity designs on school-entry age cutoffs. Across 142 effect sizes from 42 data sets involving over 600,000 participants, we found consistent evidence for beneficial effects of education on cognitive abilities of approximately 1 to 5 IQ points for an additional year of education. Moderator analyses indicated that the effects persisted across the life span and were present on all broad categories of cognitive ability studied. Education appears to be the most consistent, robust, and durable method yet to be identified for raising intelligence. </jats:p

Physical frailty and decline in general and specific cognitive abilities:The Lothian Birth Cohort 1936

Background: physical frailty is associated with many adverse outcomes including disability, chronic disease, hospitalisation, institutionalisation and death. It is unclear what impact it might have on the rate of normal cognitive ageing. We investigated whether physical frailty was related to initial level of, and change in, cognitive abilities from age 70 to 79 years.Method: participants were 950 members of the Lothian Birth Cohort 1936. Physical frailty was assessed at age 70 years using the Fried criteria. Cognitive function was assessed at ages 70, 73, 76 and 79 years. We used linear regression to examine cross-sectional and prospective associations between physical frailty status at age 70 years and factor score estimates for baseline level of and change in four cognitive domains (visuospatial ability, memory, processing speed and crystallised ability) and in general cognitive ability.Results: physical frailty, but not prefrailty, was associated with lower baseline levels of visuospatial ability, memory, processing speed and general cognitive ability after control for age, sex, education, depressive symptoms, smoking and number of chronic illnesses. Physical frailty was associated with greater decline in each cognitive domain: age-adjusted and sex-adjusted standardised regression coefficients (95% CIs) were: −0.45 (−0.70 to –0.20) for visuospatial ability, −0.32 (−0.56 to –0.07) for memory, −0.47 (−0.72 to −0.22) for processing speed, −0.43 (−0.68 to –0.18) for crystallised ability and −0.45 (−0.70 to –0.21) for general cognitive ability. These associations were only slightly attenuated after additional control for other covariates.Conclusion: physical frailty may be an important indicator of age-related decline across multiple cognitive domains

Processing speed differences between 70- and 83-year-olds matched on childhood IQ

AbstractProcessing speed is an important human cognitive capability that might underlie differences in other cognitive skills and their aging. We aimed to test aging-related processing speed differences using a novel cross-sectional design that adjusted for cognitive ability tested in youth. We examined aging differences on three different ways of assessing processing speed: psychometric, experimental, and psychophysical. We compared large narrow-age cohorts of 70- and 83-year-old people who were matched for cognitive ability in childhood. There were decrements of substantial effect size in all processing speed assessments in the older group that were not accounted for by prior cognitive ability, health, or fitness differences, though these factors also contributed to processing speed differences. These findings confirm age-related cognitive slowing using an unusual research design, and provide evidence against recent theories characterizing aging-related cognitive decline as a myth

Variations in cognitive abilities across the life course: Cross-sectional evidence from Understanding Society : The UK Household Longitudinal Study

Background: Populations worldwide are aging. Cognitive decline is an important precursor of dementia, illness and death and, even within the normal range, is associated with poorer performance on everyday tasks. However, the impact of age on cognitive function does not always receive the attention it deserves. Methods: We have explored cross-sectional associations of age with five cognitive tests (word recall, verbal fluency, subtraction, number sequence, and numerical problem solving) in a large representative sample of over 40,000 men and women aged 16 to 100 living in the UK. Results: Women performed better on word recall tests and men had higher scores for subtraction, number sequence and numerical problem solving. However, age-cognition associations were generally similar in both genders. Mean word recall and number sequence scores decreased from early adulthood with steeper declines from the mid-60s onwards Verbal fluency, subtraction and numerical problem solving scores remained stable or increased from early to mid-adulthood, followed by approximately linear declines from around age 60. Performance on all tests was progressively lower in respondents with increasingly worse self-rated health and memory. Age-related declines in word recall, verbal fluency and number sequence started earlier in those with the worst self-rated health. There was no compelling evidence for age dedifferentiation (that the general factor of cognitive ability changes in strength with age). Conclusions: We have confirmed previously observed patterns of cognitive aging using a large representative population sample

Is education associated with improvements in general cognitive ability, or in specific skills?

Previous research has indicated that education influences cognitive development, but it is unclear what, precisely, is being improved. Here, we tested whether education is associated with cognitive test score improvements via domain-general effects on general cognitive ability (g), or via domain-specific effects on particular cognitive skills. We conducted structural equation modeling on data from a large (n 1,091), longitudinal sample, with a measure of intelligence at age 11 years and 10 tests covering a diverse range of cognitive abilities taken at age 70. Results indicated that the association of education with improved cognitive test scores is not mediated by g, but consists of direct effects on specific cognitive skills. These results suggest a decoupling of educational gains from increases in general intellectual capacity