The brain is an obvious place from which to get that energy because it is such an energy hog. For example, newborns put 87% of their energy towards brain development and kids and adults use 44% and 25%, respectively.
The connection between lost energy and brain development makes intuitive sense, but where’s the proof? The main evidence for this idea comes from a recent study where the authors try to explain why average IQ varies across the world the way it does. Some countries have higher average IQs than other countries. Same thing with different regions of the world.
Lots of reasons have been put forth to explain these findings but none has really panned out. For example, one idea is that people who settled in cold places needed more brainpower to survive than did people in tropical places. As if finding a cave and lighting a fire is more taxing than surviving lions, leopards, cheetahs and who knows what else. Clearly a bit of Caucasian bias there…
The authors looked at lots of explanations like this and none of them came close to explaining the disparities as well as infection rates. They found that countries with higher chronic infection rates had a lower average IQ.
Not only that, but the authors argue that a continuing decrease in infections explains the Flynn effect. Dr. Flynn noticed that average IQs keep rising after industrialization (although ours may have leveled off in the mid-1990’s). So the idea is that a country’s IQ continues to increase as more and more of its people gain easy access to vaccinations, clean water and medicines.
If it ends up being true that infection rates and IQ are related, it raises some interesting questions for us here in the U.S. Will areas with lower vaccination rates that suffer more disease outbreaks eventually see a decline in IQ? Will the spread of parasites like the West Nile Virus because of global warming lower the national IQ?
Before ending, I should mention that having a higher IQ isn’t all sunshine and roses. Some studies are noting that countries with a higher average IQ also have more cases of allergies and asthma. One idea is that the immune system has to battle something and if there are no infections, it will turn on itself.
So there may be a trade off between IQ and allergies and asthma. If true, we may want to find that sweet spot where people get just enough infections to keep allergies and asthma at bay but maximize IQ. Or we may just want to go for maximal IQ…
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Who would have thought that vaccines would make us smarter?