Having a high IQ may help you live longer, according to a study of elderly Scots. Researchers traced more than 2200 people who took the same mental test in 1932 and found that those who scored highest were significantly more likely to be alive in 1997. It's not clear why, however.
The finding is based on a recently uncovered trove of raw data. On 1 June 1932, every 11-year-old schoolchild in Scotland sat down for the Scottish Mental Survey. The results were stashed in government archives for decades. Psychologist Ian Deary of the University of Edinburgh dug up the tests in 1997, seeing in them an unparalleled opportunity to track cognitive changes with age. Last year Deary and colleagues reported that they gave the same test to 101 of the subjects exactly 66 years later. The results demonstrated the stability of IQ throughout life. In addition, kids who scored high in 1932 today have better health and less dementia than their classmates who didn't perform as well.
In the longevity study, published in the 7 April issue of the British Medical Journal, Deary and Lawrence Whalley of the University of Aberdeen tracked the fates of about 80% of the 2792 Aberdeen test-takers. The IQ-longevity correlation was modest in men because of wartime mortality, they suggest, but in women the effect was substantial. For example, a girl with a childhood IQ of 115 was twice as likely to be alive at 77 than one with an 85 IQ. The relation persisted even when researchers controlled for father's occupation and overcrowded schools. They say the connection could be the result of high-IQ people having better jobs and access to health care, living in healthier environments, or avoiding unhealthy behaviors such as smoking. Alternatively, childhood illnesses or poor prenatal care might account for both low IQs and a short life-span.
While other research has suggested similar findings in the past, this new study adds "a good deal more certainty," says psychologist Nathan Brody of Wesleyan University in Middletown, Connecticut. He calls it "a very exciting database that encompasses virtually the entire adult life-span."