Hyperactivity, impulsiveness, and difficulty paying attention may have had evolutionary benefits, a new study has suggested.
Research from the University of Pennsylvania’s (UPenn) Wharton Behavioral Lab has drawn attention to how some traits typically viewed negatively today may have helped humans survive before the agricultural revolution.
The study, published in Proceedings of the Royal Society B: Biological Sciences this month, makes a case for the evolutionary advantage of attention-deficit/hyperactivity disorder (ADHD) by analyzing data collected from 457 adult participants playing a foraging game online.
Each player was compensated 0.3226 cents for each berry collected for a maximum of $3 on top of the $4 given for participating in the study. They were assigned to a patch and allowed to collect berries for 2 minutes before being given the choice to go to another patch, which would cost them time but potentially offer new foraging opportunities. Moreover, the berries available on a given patch declined the more often it was foraged, mimicking real-life conditions.
Alongside analyzing how participants played and performed in the game, researchers screened them for ADHD-like symptoms through a six-question survey.
While lead author Dr. David Barack, a philosopher and neuroscientist at UPenn, noted that the survey didn’t represent an ADHD clinical diagnosis, 206 participants were shown to have symptoms of this neurodevelopmental disorder, according to The Guardian.
The research team found a direct correlation between the grade of ADHD symptoms a participant had and how many berries they ended up collecting due to their willingness to abandon a given patch for a new one.
“Consistent with our reported findings, we speculate that ADHD serves as an adaptive specialization for foraging, thus explaining its widespread prevalence and continued persistence in the human population,” the authors wrote in the paper. After all, early in human history, societies had few — if any — reliable food sources, making effective foraging crucial.
Although concrete data on the prevalence of ADHD is difficult to ascertain, diagnoses among U.S. children were on the rise between 2003 and 2011 before dipping slightly between 2016 and 2019, according to the CDC.
However, since the COVID-19 lockdowns, a dramatic spike in ADHD diagnoses has been seen, which researchers are still trying to make sense of. Some studies found that ADHD correlated to COVID-19 severity and prolonged symptoms. The disorder has also been linked to a heightened risk for obesity, a critical public health issue.
Nonetheless, Barack believes that the continued prevalence of ADHD symptoms in today’s populations and the results of the study show that the random genetic mutation behind this disorder may have had its benefits.
“If [ADHD traits] were truly negative, then you would think that over evolutionary time, they would be selected against,” Barack said, according to The Guardian. “Our findings are an initial data point, suggestive of advantages in certain choice contexts.”
