Why Do We Have Emotions?

According to Charles Darwin—famous for his revolutionary theory of evolution and natural selection—a small number of basic, universal emotions have evolved in humans and animals because emotions help us to survive.

Darwin is best known for his two books that outline his Theory of Evolution (On the Origin of Species and The Descent of Man). Many are not aware that he also wrote a third book about evolution focused on emotions. Darwin's third book was The Expression of the Emotions in Man and Animals, published in 1872.

The basis for evolution is that genetic traits which help people to survive or to have more children will become more common within a group of people. This is because the people who have these traits are more likely to survive to have children who in turn will survive long enough to have children of their own (and so pass on these traits to their children through their genes).

In his third book, Darwin proposed that emotions might have evolved in humans because they confer a survival benefit.

Emotions may have evolved as responses to basic survival and reproductive needs. For example, feeling fear may lead people to run away from danger (so they are more likely to survive). Feeling disgust may lead people to spit out sour or bitter foods (which are more likely to contain toxins). People who experience these emotions are therefore more likely to live long enough to reproduce more children (because they don't die from poisoning or predators). If there are genes that predispose people to feel disgust or fear, they will become more numerous in the population as more people with these genes than without them will survive.

A fear response involves several different action tendencies. When you are scared, you might do one of four things:

• Fight: You might approach the threat and attempts to fight or overpower it,
• Flight: You might take flight (run away) to escape the threat,
• Fawn: You might seek others for comfort, reassurance, or help
• Freeze: You might stop moving (in milder terms, you may stop speaking or dissociate/act like you are not there).

Any of these responses make it more likely that you will survive the threat, and live to produce more children who have the fear response.

Darwin proposed several ideas about human emotions. These later formed the basis for modern theories of emotions. Some of the key ideas are listed below.

Darwin's Ideas about Human Emotion

1. There are a small number of universal human emotions.

By "universal," Darwin meant that the same emotions were present in all societies, in people of all ages, from all different continents, and for males and females alike. All have the same basic experience of emotions.

The basic emotion of fear

Source: Licence: Attribution-NonCommercial 4.0 International (CC BY-NC 4.0), Wellcome Collection

Different emotion theorists have different ideas about which emotions are basic and universal. Perhaps the most commonly accepted set of emotions are Paul Ekman’s six basic emotions of joy, anger, sadness, fear, disgust and surprise.

2. These universal emotions have a genetic basis.

The basis for experiencing and expressing these emotions is encoded in human DNA, which is passed down from parent to child. That is, emotions are encoded in the genes, rather than something that is learned from the environment as a baby or child.

3. Emotions link internal states with movements of the body.

Think of the examples above. Fear leads to running away or hiding (an adaptive action). Disgust leads to spitting out sour or bitter food. These kinds of body movements associated with specific emotions lead people to take specific actions that increase their likelihood of survival.

4. The expression of emotions serves a communication function that is adaptive for survival.

Children do not generally speak fluently until 2 or 3 years of age but can express their emotions (anger, fear, sadness) from a very young age, conferring survival benefit. Emotions as a communication system (fear ="there's danger!" disgust = "this food is bad," happiness = "everything is safe") may pre-date language as a communication system. In fact, Darwin believed that primates and other animals also displayed these same basic emotions.

The key point is that emotions (even unpleasant emotions like fear or sadness) can be adaptive and beneficial. They have evolved to help us stay safe, quickly communicate with others, and rapidly respond to threats.