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Evolutionary Psychology

Reviewed by Psychology Today Staff

The human body evolved over eons, slowly calibrating to the African savanna on which 98 percent of humankind lived and died. So, too, did the human brain. Evolutionary psychology is the study of the ways in which the mind was shaped by pressures to survive and reproduce. Findings in this field often shed light on "ultimate" as opposed to "proximal" causes of behavior. Romantic jealousy and mate guarding are proximally intended to keep one's relationship intact. Ultimately, though, the behavior can be explained by the fact that for most of human history, losing a romantic partner jeopardized one's ability to reproduce and raise children.

The Science of Evolutionary Psychology
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Natural selection has a lot to do with human behavior. In fact, our behavior is naturally selected just as our physical traits are naturally selected. We are much taller and live longer than our ancestors. Through centuries of generations, evolution has helped us pass along adaptive behaviors that promote our reproduction.

What are some basic principles of evolutionary psychology?

Evolutionary biologist Robert Trivers proposed a number of theories on evolutionary psychology, including why we engage in reciprocal altruism, the nature of sex differences, and parent-offspring investment. Altruism among strangers, for example, can naturally develop because people cooperate with the expectation of receiving similar treatment from others.

What is evolutionary behavior?

Our hunter-gatherer ancestors passed down behavioral traits that are, for the most part, advantageous to us. For example, we are mindful of danger in dark alleyways. This caution is innate and within our behavioral make-up. And our predetermined response to gravitate to that 800-calorie Cinnabon can wreak havoc, but our ancestors made us do it.

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Concepts In Evolutionary Psychology
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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 the chances for survival. Many of these behaviors are innate: How people react and interact with one another is spelled out in DNA.

What is the fight-or-flight response?

Fight or flight refers to the human body’s built-in 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.

What triggers fight or flight?

Any fearful situation can trigger it, whether it is physical danger or a stressful event, like running late for a meeting. In people with anxiety, the fight-or-flight response is more readily triggered, the brain sees certain situations as threatening, even when there's no actual present danger. In fact, there is a tendency for this response to move into overdrive in anxious individuals.

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.

Why are we naturally empathic?

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. What is better for the group as a whole, is better for a person as an individual.

Why are we naturally drawn to our tribe?

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 and what we define as “right” and “wrong.”

Why Evolutionary Psychology Is Controversial
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People reject evolutionary psychology for ideological reasons. With sexual behavior, for example, there is the notion that the field justifies people’s behaviors and actions. Our present-day traits and characteristics had survival value for our ancestors, and these traits survived because the genes they are linked to were selected and now remain part of our genetic makeup. Shouting evolution made me do it seems so convenient.

What is the naturalistic fallacy?

This refers to common but faulty logic wherein people assume that because something is "natural" it is therefore "good" or just. Violence and aggression are found in all human societies, but that does not make this acceptable behavior. No endorsement is implied in a discovery of what is natural. The general public commits the naturalistic fallacy in thinking that evolutionary psychologists endorse certain findings (such as violence or rape), when in fact evolutionary psychologists are simply outlining reasons that these behaviors may occur.

What is the moralistic fallacy?

The moralistic fallacy is the false belief that the world operates as we wish it would, that what ought to be is in fact the truth, or that because we wish something were not true, it cannot be true. People sometimes reject evolutionary theorists' findings about human nature because they do not want to believe that said findings are true.

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