Genetics and education are often cited as the biggest influences on intelligence, but a new study claims that disease has far more sway on IQ than either of these.
Scientists from the University of New Mexico analyzed IQs across the United States and declared that exposure to infectious disease had a huge effect on brain power.
They say 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 diverts that energy, then intelligence inevitably suffers.
Writing in Scientific American, 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."
Mr. Eppig said: "The states with the five lowest averages IQ all have higher levels of infectious disease than the states with the five highest averages IQ."
埃皮格先生说:“与平均智商水平最高的五个州相比,智商水平最低的五个洲都存在较严重的传染性疾病。”
Eppig hopes his hypothesis will allow people wishing to help raise IQs around the globe to do so more efficiently.