ADHD may have evolved to help foragers know when to cut their losses

Symptoms of attention deficit hyperactivity disorder, such as impulsivity, may have helped foragers in hunter-gatherer communities quickly move on to new areas when food sources were low

By Chen Ly

21 February 2024

Early hunter-gatherers who faced food scarcity may have benefitted from the impulsivity that can come with ADHD

JOHN SIBBICK/SCIENCE PHOTO LIBRARY

Attention deficit hyperactivity disorder (ADHD) may have evolved in hunter-gatherer societies because it was advantageous for foragers, according to the results of a new study. Traits that are commonly associated with the condition, such as impulsivity, might have encouraged some foragers to move on from areas with depleting resources to more bountiful harvests sooner than those without the condition.

ADHD affects people’s behaviour, which may result in them acting on impulse or having difficulty concentrating. Its exact cause isn’t fully understood, but the condition tends to run in families.

Its origin is similarly unclear, says Arjun Ramakrishnan at the Indian Institute of Technology Kanpur. “Is it a legacy of the hunter-gatherer world?”

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To explore this, Ramakrishnan, David Barack at the University of Pennsylvania and their colleagues recruited 506 people in the US to play an online foraging game. The players were instructed to collect as many berries as they could in 8 minutes by hovering their cursor over bushes.

They were given the choice to either stay at a bush or to try their luck by leaving for another, which may have more or fewer berries. Moving to a new bush also incurred a brief time out, so the players had to balance the benefits of potentially getting more berries with the time lost due to moving on.