The hunter vs. farmer hypothesis is a proposed explanation of the nature of attention-deficit hyperactivity disorder first suggested by radio hostThom Hartmann in his book Attention Deficit Disorder: a Different Perception. This hypothesis proposes that ADHD represents a lack of adaptation of members of hunter-gatherer societies to their transformation into farming societies. Hartmann developed the idea first as a mental model after his own son was diagnosed with ADHD, stating, "It's not hard science, and was never intended to be." However, more recent molecular and clinical research has given support to a genetic deflection ”theory” of ADHD arising from evolutionary adaptation Hartmann notes that most or all humans were nomadic hunter-gatherers for hundreds of thousands of years, but that this standard gradually changed as agriculture developed in most societies, and more people worldwide became farmers. Over many years, most humans adapted to farming cultures, but Hartmann speculates that people with ADHD retained some of the older hunter characteristics. A key component of the hypothesis is that the proposed "hyperfocus" aspect of ADHD is a gift or benefit under appropriate circumstances. The hypothesis also explains the distractibility factor in ADHD individuals and their short attention span for subject matter that does not interest the individual which they are forced to waste their life on, along with various other characteristics such as apathy towards social norms, bad/lazy parental oversight, poor planning and organizing ability, distorted sense of time, impatience, attraction to variety or novelty or excitement, and impulsiveness. It is argued that in the hunter-gatherer cultures that preceded farming societies, hunters needed hyperfocus more than gatherers.
Nomadic populations
A genetic variant associated with ADHD has been found at higher frequency in more nomadic populations and those with more of a history of migration. Consistent with this the health status of nomadic Ariaal men was higher if they had the ADHD associated genetic variant. However, in recently sedentary Ariaal those with 7R alleles seemed to have slightly worse health.
The hunter vs. farmer hypothesis proposes that the high frequency of ADHD in contemporary settings "represents otherwise normal behavioral strategies that become maladaptive in such evolutionarily novel environments as the formal school classroom." One example such as migration in the hunter-gatherer society, is that some of these hunter-gatherers that naturally predisposed to these various amounts of this same gene may have value in certain kinds or qualities of social groups. It was also stated that the lack of 'hyperfocus' should not be the only dichotomy of 'Farmers vs. Hunter-gatherers' that was identified in Hartman's theory. From an evolutionary viewpoint, "hyperfocus" was advantageous, conferring superb hunting skills and a prompt response to predators. Also, hominins have been hunter gatherers throughout 90% of human history from the beginning, before evolutionary changes, fire-making, and countless breakthroughs in stone-age societies. Humans devised better innovations and organizational structures to boost their living, and the need for hyperactivity slowly diminished over a long period of time regardless of whether they were in a gathering or farming society. K. H. Ko further states that decreased need for 'hyperfocus' was building the conditions for human language. Genetic variants conferring susceptibility to ADHD are very frequent—implying that the trait had provided selective advantage in the past. Glickman & Dodd found that adults with self-reported ADHD scored higher than normal adults on self-reported ability to hyper-focus on "urgent tasks", such as last-minute projects or preparations. Adults in the ADHD group were uniquely able to postpone eating, sleeping and other personal needs and stay absorbed in the "urgent task" for an extended time. A 2008 New Scientist article by Tim Callaway reports that research of ADHD and related traits in different cultures offers some support for the hunter vs. farmer hypothesis. According to evolutionary anthropologistBen Campbell of the University of Wisconsin–Milwaukee, studies of the Ariaal, an isolated nomadic group in Kenya, suggest that hyperactivity and impulsivity—key traits of ADHD—have distinct advantages to nomadic peoples. Additionally, nomadic Ariaal have high rates of a genetic mutation linked to ADHD, while more settled Ariaal populations have lower rates of this mutation. Henry Harpending of the University of Utah reports that with this genetic mutation, "You probably do better in a context of aggressive competition."
