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The Human Zeal for Adventure Has a Genetic Basis

A new study shows that a gene identified in fruit flies may help explain why some of us take risks—and some stay at home

Credit: HeitiPaves/Getty Images

AsAs humans, we like to think that we occupy a special place within the animal kingdom, and we’re often surprised when we see other animals expressing humanlike qualities. Even our closest living relatives—other primates—impress us by using basic tools or expressing emotions. But if we profiled our commonalities with other species in detail, we might be less likely to harbor exaggerated perceptions of human superiority. The best way to dispel illusions about what it means to be human is to compare our behaviors to the behaviors of the simplest animals we can find — including Drosophila, also known as humble fruit fly.

There’s one particular behavioral question that unites many animal species: “Should I explore the wider environment or exploit my current environment?”

For most animals, the question relates to whether they should remain in a familiar location, where they understand the availability of food and risks from predators, or explore entirely new and potentially dangerous environments in order to improve their options. For humans in the developed world—unlike for many animals—the question usually lacks fatal consequences. But it can still apply to the most important decisions in our lives, like whether I should keep my current low-risk job or aim higher and start the business I’ve always wanted.

There’s a gene that underlies this behavior in fruit flies commonly referred to as the “foraging gene.” It has two specific variants: One is thought of as a “rover” variant, which predicts wider and more comprehensive search paths during exploration. The other can be thought of as the “sitter” variant, which predicts a more conservative exploration style. The rover variant of the gene predicts more adventurous exploration by fruit flies and ultimately a heightened ability to find food sources within uncertain environments.

These differences in behavior seem to relate to risk aversion. A fly willing to explore widely and adventurously is more likely to find new food sources, but it also leaves itself open to new dangers like crossing a predator’s territory. A fly that sticks to exploiting nearby environments, and remaining as sheltered as possible in its search patterns, may find fewer food sources but also fewer dangers associated with uncertain territory.

In a recently published study in the journal PNAS, a group of researchers tested whether the human equivalent of the foraging gene, known as PRKG1, may also predict how humans explore the world. Previous evidence already highlights a role of this gene in regulating human behavior, including potential links to traits such as a mother’s maternal sensitivity and responsiveness toward her infant. Given the gene’s connection to foraging in fruit flies and its existing links to some general human behavioral traits, the researchers wanted to understand whether PRKG1 would predict adventurousness in human exploration.

The researchers recruited 450 undergraduate students from the University of Waterloo in Ontario. Each offered up a saliva sample for genetic testing and completed a questionnaire that assessed adventurous tendencies by asking for levels of agreement with statements such as, “by the time I accomplish a task, I already have the next one in mind.” Answers to these questionnaire items identified whether people leaned more toward a “do the right thing” mindset, or a “just do it” mindset.

As we hack further into our genetic code, we realize that our innate biological fortuities predict many of our decisions and characteristics.

The less adventurous “do the right thing” mindset cautiously evaluates options before jumping into decisions and aims to avoid making mistakes due to premature actions. In contrast, the more adventurous “just do it” mindset commits to spontaneous decisions and impulsive actions that minimize the fear of missing out.

The college volunteers then played a game where they were asked to find as many berries as they could in a computerized environment. By analyzing people’s search patterns, the researchers identified different exploration styles. They also located two forms of the human PRKG1 gene and discovered that one of these forms resembled the fruit fly sitter variant.

People with this human sitter variant had a more cautious “do the right thing” mentality and were more likely to stick to the game’s external boundaries as they explored. They were also highly persistent in picking up difficult smaller berries within the playing field. In other words, they were not only more cautious in their global search patterns, they also carefully collected all available berries on sight rather than exploring more widely and aiming for easy targets—a classic marker of a risk-averse individual.

Fascinatingly, this behavior parallels the actions of fruit flies that have the cautious sitter variant of the foraging gene. Just like their human peers, these flies hug the boundaries of a foraging environment and avoid adventurous search strategies that cover extensive territory but raise their exposure to risks.

How could the PRKG1 gene have these effects in humans? The researchers suggest that it could relate to how the genes are expressed in an area of our brain known as the dorsolateral prefrontal cortex. Those of us who may be cautious in our exploration show fewer products of the PRKG1 gene within our prefrontal cortex. And, with this trait, we once again parallel the humble fruit fly: Those flies who are classified as cautious sitters, rather than adventurous rovers, have less productive foraging genes.

We’ve yet to see an independent study that replicates this effect and tests the same question among older age groups. As with most scientific research, it’s worth waiting for more evidence. But the data highlights an obvious but frequently overlooked fact about human nature: Our genes may affect our behavior. When we consider how we explore the world—how we roam around a new city or travel around a large museum—we attribute our choices to what we might call “free will.” But as we hack further into our genetic code, we realize that our innate biological fortuities predict many of our decisions and characteristics. Our genes, and their interactions with the environmental influences in our lives, play a crucial role in determining whether we ultimately become adventurers or homebodies.

Our foraging behavior may be similar to the humble fruit fly, but we set ourselves apart with our ability to consciously reflect on that behavior and understand our motivations. The triviality and brevity of human life in our universe should drive us to appreciate every fortunate moment of our conscious experience—whether we prefer the comfort of home or the adventure of abroad.

Neuroscientist writing about brains, behavior, & health. “Understand more, so that we may fear less” — Marie Curie.

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