Correlation between infectious diseases and IQ?
Eliminate poverty and stop the blight of human potential!
In the Science and Technology column of The Economist, I saw an article that proposed an intriguing correlation between the occurence of infectious diseases in countries and the IQ of the people in those countries. Sounds like a pretty audacious correlation to make, but it seems like the research done by these scientists from the University of New Mexico (which is, by the way, in America and not Mexico) seems to bear this out.
One's IQ might be genetically influenced, but why does IQ vary across places, being on average higher in certain places and lower in others? And apparently IC seems to be "rising in recent decades". The hypothesis of the researchers assert that the occurence of infectious diseases affect IQ variation. In other words, "places that harbour a lot of parasites and pathogens... have their human caiptal eroded, child by child, from birth".
This sounds scary and damning, but the link is not exactly impossible. From newly born children to adult, the brain uses a huge proportion of the body's metabolic energy far exceeding its weight within the body, from 87% in a newborn to "about a quarter of the body's energy" even as an adult, when your brain weighs "a mere 2%" of your body weight. When parasites and pathogens (that cause infectious diseases) reside in the body, they can damage the body tissue, provoke immune system reactions and / or compete for resources such as nutrients from food consumed.
Statistically plotting infectious disease burden on life years lost against average IQ, the more developed countries with "relatively low levels of disease" have a higher average IQ and vice-versa. Singapore features prominently as the country with the highest average intelligence with relatively low infectious disease burden. "Correlation is not causation", certainly, and the researchers have considered some alternative causes for lower IQ but these seem to diminish in importance when measured vis-a-vis the consequences of disease.
The importance of this study? If further research validates this groundbreaking postulation, the onus upon developing countries to develop economically and improve healthcare becomes even greater as the consequent health problems from low levels of development damage the country's potential. These countries may be stuck in a vicious cycle, but then the onus is also upon the developed countries to provide aid and assistance to the developing countries to break out of this disease-potential trap. Indeed, as the writer valiantly suggests, it is time for policymakers to recognise that "one of the main aims of development" would be to eliminate disease, instead of doing so as "a desirable afterthought".