Recycling,evolution and the structure of human personality

Lower childhood cognitive ability may be a risk factor for greater cognitive decline in late life and progression to dementia. To assess variation in age-related cognitive change, it is helpful to have valid measures of cognitive ability from early life. Here, we examine the relation between childhood intelligence and cognitive change in later life in two samples, one born in 1921 and the other in 1936. All participants completed the same test of mental ability (one of the Moray House Test series) at age about 11 years, and were re-examined on Raven’s Progressive Matrices at age 77 (1921-born) or age 64 (1936-born). Where possible, the 1921 sample was re-tested at the age of about 80 years old and the 1936 sample re-tested at about 66 years. After taking into account various covariates, including sex, education and occupation, childhood intelligence was a significant predictor of cognitive change in later life. Results were in the direction that participants with lower childhood mental ability experienced relatively greater cognitive decline, whereas those of higher childhood mental ability showed improved performance. This result suggests that higher premorbid cognitive ability is protective of decline in later life.