ADHD may have emerged in humans as an evolutionary advantage, study finds

ADHD may have emerged in humans as an evolutionary advantage, study finds

Attention Deficit/Hyperactivity Disorder or ADHD may have evolved as an advantageous adaptation among foragers in hunter-gatherer societies, a new study says.

ADHD is a common behavioral condition affecting about 11 per cent of children and lasting to adulthood in about 4 per cent of people with symptoms, including distractibility, restlessness, forgetfulness, impulsivity, and hyperactivity.

In modern days, the symptoms may cause difficulties for children at school, contribute to low self-esteem, or cause hurdles in relationships or at work for adults.

Children with ADHD may cycle more frequently between information sources in classrooms, or seek new kinds of stimulation at home.

However, the new study suggests some of these traits such as impulsivity may have encouraged early foragers in hunter-gatherer societies to quickly move on from areas with depleting resources to those offering more.

Researchers suspect this exploratory behaviour of individuals with ADHD in early societies may have offered them an evolutionary advantage.

Finding food in difficult situations is thought to be one of the main drivers of human intelligence.

For instance, while foraging, people are forced to decide whether to stick to a known patch of land or to disengage and search for new pastures.

People with ADHD may tend to abandon their current resource patch and search for a new one, researchers thought.

The new study tested this hypothesis by having human participants collect resources in an online foraging task and then complete an ADHD self-report screening assessment.

About 200 of the 457 screened positive for ADHD.

Participants could choose to either continue collecting rewards from a depleting patch of resources or replenish the patch.

Scientists found that the people who screened positive for ADHD departed resources sooner and earned higher reward rates than those who screened negative.

Indeed, this has also been documented in modern-day nomadic populations such as the Ariaal tribe of Africa who favour exploration and are characterised by genetic mutations implicated in ADHD.

The latest findings suggest ADHD attributes provide advantages while foraging, suggesting that the condition is a beneficial adaptation for exploration.