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Over the years, people have put forth a lot of theories to explain why intelligence differs, from person to person and even around the world. Health, wealth, schooling, nutrition, and even climate have all come up. Now, researchers at the University of New Mexico suggest that parasites might play a role. They find that the prevalence of infectious diseases can be a powerful predictor of regional smarts. Their work appears in the Proceedings of the Royal Society. [Christopher Eppig, Corey Fincher and Randy Thornhill, http://bit.ly/c2E4wD]
It takes a lot of energy to build and operate a human brain. This needy organ commands 87 percent of the body’s metabolic budget in infants, and about 25 percent in adults. So things that sap our energy are likely to hinder our intellectual growth. That’s why malnourishment’s not good for the mind.
But what about parasites? Fighting off nasty bugs can take a lot out of you. So the scientists got to wondering whether excessive infections might correlate with impaired cognitive development. Looking at IQs from around the world, they found that high levels of infectious disease go hand in hand with lower average national intelligence.
Although the authors have not demonstrated cause-and-effect, it’s nice to think that taking down parasites could bring up our IQs.
—Karen Hopkin
[The above text is an exact transcript of this podcast.]
See also Does national IQ depend on parasite infections? Er...
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8 Comments
Add CommentThe obvious question is "Why did they assume that parasites cause lower intelligence?" Couldn't lower intelligence put populations at risk for parasites?
Reply | Report Abuse | Link to thisyes, that would be the obvious question, hence that last line on cause-and-effect......
Reply | Report Abuse | Link to thisI agree with the last two comments. It would seem that in places where the average intelligence is lower (generally Less Developed Nations), there would be less advanced technology, meaning a worse access to medical care, meaning higher infectious disease rates. Also, places with lower intelligence tend to be more unsanitary, with bad sewage systems, unfiltered water, etc.... It would seem that you have this backwards.
Reply | Report Abuse | Link to thisIn regard to the effect of parasites, WHO established a program for helminth control in school-age children due to the observed reduction in fluency and cognitive abilities in those suffering helminth infections. Therefore, this idea is not necessarily new, but I am glad more effort is being done to determine the effects of infections with parasites.
Reply | Report Abuse | Link to thissamwise - Exactly. Not to mention education (which may not directly affect intelligence but can affect test scores). There are likely a large number of interrelated contributing factors in the reduction of adult intelligence. It's foolish to spend time and money to consider each independently, looking for that magic bullet.
Reply | Report Abuse | Link to thisPerhaps it would be more effective to find humane methods of reducing reproduction in regions that cannot support healthy populations.
Personally i think, infection disease do not have an DIRECT connection with lower intelligence. Since infection disease can be caused by less wealth, lower medical facilities and so on, which actually are the really "killer" of intelligence..
Reply | Report Abuse | Link to thisWhat did the great ancient civilizations of GREECE, EGYPT, INDIA (INDUS VALLEY), MESOPOTAMIA have in common? They all sprouted in TROPICAL regions during an age when the cold-climate tribes of Europe were still largely semi-troglodytes. How do you explain that in light of this research? Actually, the only pattern I see when I look at the countries/regions most often cited (or hinted at) as low-IQ societies is that they are almost invariably peoples who were bled the longest by -- or suffered the most deprivation under -- COLONIAL RULE by the Brits, the French, the Belgians, the Dutch and the Iberian powers. Their societies were so badly scarred by policies of divide-and-rule, institutionalized racism, sucking out of resources and the creation of arbitrary borders that they are still desperately struggling to lift education, health and nutrition standards.
Reply | Report Abuse | Link to thisAny serious discussion should take words with care, I don't see how one can write things like the first three comments without a good amount of racist (or country-discrimination) prejudices. This discussion is out of limits and opinions from some people here are far away from information and clearly racist. I agree that as any complex issue, it is important separate cause and effect. Before testing more elaborated ideas, I would question the bases and methods of these studies, like how effectively can we measure intelligence by IQ tests in all societies, and even our definition of it. This topic is controversial even between the informed (one needs to read a bit about Richard Lynn writings and life to easily note what prejudices can make with scientific research, although skillfully exposed) but this makes me suppose that this field about IQ and society needs a comprehensive, methodological and scientific revision, not just personal impressions.
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