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Evolutionary Psychology

What Is Evolutionary Psychology?

The human body evolved over eons, slowly calibrating to the African savanna on which 98 percent of human ancestry lived and died. So, too, did human brains. According to evolutionary psychologists, the mind is shaped by the pressure to survive and reproduce, and so our emotions, communication skills, and language ability represent adaptations that enabled our human ancestors to thrive.

Many of the behaviors people exhibit have been tools for self-preservation: Homo sapiens jealously guard their romantic partners because competition for mates has always been harsh. Everyone cherishes their closest kin because it's in one's best interest to preserve one's genes. Humans also crave social interaction to encourage cooperation, further increasing their chances for survival. Many of these behaviors are innate: How people react and interact with one another is spelled out in DNA.

Juggling our ancestral tendencies with the demands of modern-day living can be a struggle. This is the phenomenon known as evolutionary mismatch—when we find ourselves in an environment inconsistent with our ancestral conditioning. A good example of this is the contemporary diet: Ten thousand years ago, people battled starvation. They had to pile on the necessary calories just to survive lean times; high-fat meats and high-sugar foods were a luxury. Today, however, fatty foods and processed sugars are readily available at low cost. Our pre-determined response to gravitate to that 800-calorie Cinnabon can wreak havoc, but our ancestors made us do it.

Who Are You? Human Nature, Explained

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Our emotional complexity differentiates us from other members of the animal kingdom. Evolutionary psychology seeks to explain how our emotions and other aspects of being human served as advantages to our ancestors.

Like other social primates, we experience emotions beyond primal fear and anger. Through evolving as a group, we have developed empathy and altruism, which allow us to commiserate with each other’s circumstances and act in ways that are not self-serving. We have also developed emotions to help keep us in line—for example, shame motivates us to atone for past transgressions, while pride pushes us to remain in the high regard of our peers. And as our social structures developed, so did our value systems—what we define as “right” and “wrong.”

The Fight or Flight Response


"Fight or flight" refers to the human body’s innate response to a perceived threat: It prepares the body to either face danger or quickly run from it. During flight or flight, the brain releases stress hormones, pushing the body into high alert. The heart rate rises, muscles tense, and thoughts race. While the modern-day human does not face the same threats as our ancestors did, the fight-or-flight response system remains intact. Any fearful situation can trigger it, whether it is physical danger or a stressful event, like running late for a meeting.

In people with an anxiety disorder, the fight-or-flight response is more readily triggered, and the brain sees certain situations as threatening, even when there's no actual present danger.

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