Attention Deficit Hyperactivity Disorder may have been an evolutionary asset back in the day, writes William Saletan on Slate.
Researchers compared African children from the same tribe with a gene linked to short attention spans and unpredictable behavior. It seems to help those who live as nomadic herders and hurt those who live in farming communities.
It might be that the attention spans conferred by the DRD4/7R genotype allow nomadic children to more readily learn effectively in a dynamic environment (without schools), while the same attention span interferes with classroom learning.
Unpredictability may help nomads defending their cattle from raiders — who wants to deal with the crazy guy? — but prove a deficit for farmers who sell their crops at market.