Disease the biggest factor in determining IQ

Updated on: Tuesday, September 13, 2011

Stay healthy to stay smart, says a new study which has found that disease -- and not education -- is the biggest factor in determining how clever one is.

Researchers from the University of New Mexico analysed IQs of people across the US and concluded that exposure to infectious diseases had a huge effect on brain power, the 'Daily Mail' reported.

According to them, the reason for this is that humans and especially children devote a great deal of energy running their brains. If a disease crops up that perts that energy, then intelligence inevitably suffers.

Lead researcher Christopher Eppig said: "Infectious disease is a factor that may rob large amounts of energy away from a developing brain. The evidence suggests that infectious disease is a primary cause of the global variation in human intelligence."

The researchers put various theories about what affects IQ levels to the test, including education and wealth and the idea that the further someone lives from sub-Saharan region, they cleverer they are.

The thinking behind this is that the brain doesn't need to try as hard to ensure survival in the area where man evolved, his ancestral home. As conditions varied dramatically elsewhere, more thinking was needed to survive so IQs went up.

However, after looking at intelligence levels across America, the researchers dismissed these theories.

Eppig wrote: "The states with the five lowest average IQ all have higher levels of infectious disease than the states with the five highest average IQ, and the relationship was good across all of the states in between."

According to the researchers, their hypothesis will allow people wishing to help raise IQs around the globe to do so more efficiently. "If the primary factors were genetic, as some have suggested, IQ would be very difficult to change," they wrote in the 'Scientific American' journal.

Disease the biggest factor in determining IQ

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