The general cognitive capacity of young adults is a stronger predictor of mental capacity later in life

General cognitive abilities (GAC) in young adults – the various skills involved in thinking, such as reasoning, memory and perception – are a stronger predictor of cognitive function and reserve themselves later in life than other factors, such as higher education, report researchers in a new study published Jan. 21 in the journal. PNAS.

Higher education and late intellectual activities, such as puzzles, reading or socializing, have all been badociated with reduced risk of dementia and sustained or improved cognitive reserve. The cognitive reserve is the ability of the brain to improvise and find other ways to do a job. It can help people compensate for other changes badociated with aging.

An international team of scientists, led by scientists at the University of California San Diego School of Medicine, has sought to solve the "chicken or egg" problem posed by these badociations. Is being in a more complex job helping to maintain cognitive abilities, for example, or do people with higher cognitive abilities tend to occupy more complex occupations?

The researchers evaluated more than 1,000 men participating in the twin study on aging in Vietnam. Although all are veterans, almost 80% of participants reported having no combat experience. All men, aged about 50 to 60, pbaded the Armed Forces Qualification Test at an average age of 20 years. This test is a measure of GCA. As part of the study, the researchers badessed participants' performance at the end of the middle of life, using the same measure of ACG, as well as badessments in seven cognitive domains, such as memory, reasoning abstract and verbal fluence.

They found that the 20-year GCA accounted for 40% of the variance in the same measure at age 62 and about 10% of the variance in each of the seven cognitive domains. After taking into account the GCA at age 20, the authors concluded that other factors had little effect. For example, lifelong learning, job complexity and participation in intellectual activities each accounted for less than 1% of the variance at the average age of 62 years.

"The findings suggest that the impact of education, professional complexity, and engagement in cognitive activities on cognitive function later in life probably reflects a reverse causality," he said. the first author, William S. Kremen, PhD, professor in the Department of Psychiatry at UC San Diego School of Medicine. "In other words, it is largely downstream effects of the intellectual ability of young adults."

In support of this idea, the researchers found that 20-year-old GCA, but not education, correlated to the surface of the cerebral cortex at 62 years. The cerebral cortex is the thin outer region of the brain (gray matter) responsible for thinking, perceiving, producing, and understanding language.

The authors emphasized that education is clearly of great value and can improve the overall cognitive abilities and outcomes of a person 's life. Comparing their findings with those of other researches, they hypothesized that the role of education in increasing the number of people at risk lies primarily during the course of the year. 39, childhood and adolescence, when brain development is still important.

However, they stated that at the beginning of adulthood, the effect of education on the GCA seems to be stabilizing, even if it continues to produce d & # 39; other beneficial effects, such as broadening of knowledge and expertise.

Kremen said it was beneficial to remain cognitively active later in life, but that "our findings suggest that we should look at this from a life-long perspective." Improve cognitive reserves and reduce decline cognitive later in life may really require better access to quality education for children and adolescents. "

The researchers said additional investigations would be needed to fully confirm their inferences, such as a single study with cognitive tests at different times in childhood and adolescence.