For a long time we have known that longevity tends to increase with IQ. Obviously this was because smarter people paid more attention to medical advice – (“More Doctors Smoke Camels”, put your baby on its stomach). But maybe not. Recent work suggests that most of the variance in IQ is explained by rare deleterious variants – mutational load. If correct, it might be that smarter people have fewer screwed-up genes than average, and live longer because they’re in better genetic shape. Plausible, since most genes influence IQ.
Assume that is the case: all else equal, higher IQ means lower genetic load and greater longevity. Then a group with higher-than-average IQ might well live longer. The same selective forces that increased IQ would have decreased genetic load. Not that differences in genetic load have to be the only factor influencing IQ and longevity – chimps probably have lower genetic load than humans, because of their larger effective population size over the long term – but they’re still dumb and short-lived, compared to humans. For that matter, herring probably have even lower genetic load – it’s not enough.
Unless lox is nootropic, Ashkenazi Jews have probably experienced selection for higher intelligence. So probably they ended up with lower-than-average genetic load [not counting deleterious genes that became common by founder effect or by conferring heterozygote advantage for intelligence (or something other trait favored in their niche)].
Under these assumptions, Ashkenazi Jews should live longer. And they apparently do, judging from UK census info. “According to British census data, Jews live an average of five to six years longer than their gentile counterparts, and there may be nearly three times as many Jewish centenarians as in the general U.K. population.” “Barzilai and his colleagues reported in the Journal of the American Geriatrics Society that Jews who make it past 95 have dietary habits and levels of alcohol consumption and physical activity similar to their shorter-lived counterparts — suggesting that genes for exceptional longevity could do more than behavior to support long life.” “They were protected by their genes,” Barzilai said. “Not the environment.”
This can’t be the only thing affecting longevity. Time since since the agricultural transition probably matters. Long-term pathogenic exposure influences the strength of the immune response, which has side effects…
But if Ashkenazi Jews live longer than Italians or Levantines, you have to wonder if it’s caused by selection. Worth checking out.