What Are Emotions and Why Do We Have Them?

Imagine you are walking home at night and you hear footsteps behind you. Before you have had a single clear thought, your heart is beating faster, your attention has narrowed to the sound and your legs are already walking a little quicker. Then the footsteps turn into a neighbor saying hello, and the whole thing drains away in a few seconds, leaving you slightly shaky and a bit embarrassed.

That small episode contains almost everything there is to know about emotions. They are fast. They involve the whole body, not just the mind. They come with a push to do something. And they are not always right.

So what exactly are they, and why did we end up with them?

A simple definition

An emotion is a short-lived reaction to something that matters to you. Most researchers agree it has several parts working together:

• An appraisal: a quick, often automatic judgment of what is happening. Threat, loss, unfairness, reward.
• A body response: changes in heart rate, breathing, muscle tension, digestion and hormones.
• An expression: what shows on your face, in your voice and in your posture.
• An action tendency: a pull toward doing something particular. Run, fight, hide, approach, cry, laugh.
• A feeling: the part you are aware of, the inner experience you might describe as “I feel scared”.

Moods are related but different. A mood is longer, vaguer and often not clearly about anything. You can be in an irritable mood all day. An emotion is usually about something specific and passes in seconds or minutes, unless something keeps feeding it.

Where do emotions come from?

For a long time, the popular picture was simple: a small set of basic emotions, each with its own circuit in the brain and its own facial expression, the same in every human culture. The psychologist Paul Ekman, whose research in the 1960s and 1970s included work with a remote community in Papua New Guinea, argued that a handful of expressions, including happiness, sadness, anger, fear, surprise and disgust, are recognized across very different cultures.

More recent research has added nuance. Lisa Feldman Barrett and others have shown that the brain does not seem to have one dedicated circuit per emotion, and that people’s faces don’t reliably show the same expression for the same feeling. In her view, the brain constructs emotions on the spot, using signals from the body, the situation and everything you have learned about what feelings are called and what they mean.

The two views still argue, but for everyday life they meet in a useful place. Your emotions are built from a mix of ancient body systems and what you have learned. That is why some reactions feel automatic, and why you can still change how you relate to them.

Why we have emotions

If emotions were only a nuisance, evolution would have trimmed them long ago. They stayed because they solve problems that every human being faces. The psychologists Leda Cosmides and John Tooby described emotions as programs that coordinate the whole body to deal with recurring situations: a predator, a rival, a loss, a chance to find a mate.

Looked at that way, each emotion has a job.

Fear keeps you safe

Fear prepares the body to escape or defend itself: faster heart, more blood to the muscles, sharpened attention to the threat. In a world of predators and cliffs, people who felt fear quickly survived more often. Today the same system fires for exams, phone calls and difficult conversations, which is one reason anxiety is so common. We look at that in How to Manage Anxiety.

Anger defends what matters

Anger arises when something you care about is blocked or threatened, especially when it seems unfair. It gives you energy and the willingness to stand up for yourself. The psychologist Aaron Sell and colleagues have argued that anger evolved partly to negotiate better treatment: it signals that someone has not given enough weight to your interests.

Sadness helps you take in a loss

Sadness slows you down, pulls your attention inward and often brings tears. It may seem to have no use, but it gives you time to absorb a loss and adjust your plans. Tears and a sad face also tend to draw comfort and help from others.

Disgust protects your health

Disgust makes us pull away from rotten food, bodily waste and signs of disease. It probably helped our ancestors avoid infection. In humans it has also spread to the moral world: we talk about being disgusted by cruelty or cheating.

Guilt and shame keep groups together

Humans have always depended on their group. Guilt pushes us to repair harm we have done. Shame, embarrassment and pride help us track how we stand in the eyes of others. They can be painful, but they kept our ancestors in good standing with the people they needed.

Joy, love and interest pull you toward good things

Positive emotions have their own jobs. Barbara Fredrickson’s broaden-and-build theory proposes that feelings like joy, interest and love widen our attention and make us more open, playful and curious. Over time, that openness builds friendships, skills and resilience that help when harder days come. We explore these feelings in Positive Emotions and How to Be Happy.

Emotions are also messages to other people

Emotions don’t only act on you. They speak to everyone around you. A frightened face warns others of danger. An angry tone says stop. Tears invite comfort. A smile says you are safe to approach. Even small children read these signals long before they understand words.

That is why hiding emotions completely can make relationships harder. Other people lose information about how you are and what you need.

Emotions help you decide

It is common to think good decisions are made with reason, and emotions get in the way. The neuroscientist Antonio Damasio found something surprising when he studied patients with damage to a part of the brain involved in emotion. Their reasoning was intact, yet they struggled badly with everyday decisions, sometimes spending a long time weighing up which day to book an appointment. Without the gut sense of what mattered more, every option looked equally good.

Emotions are part of how we know what we care about. They are not the enemy of good judgment. They are one of its ingredients.

So why do they cause so much trouble?

If emotions are so useful, why do they so often feel like a problem? A few reasons:

• They were built for a different world. The fear that saved us from a predator now fires before a presentation.
• They are fast and approximate. They react to what something looks like, not what it is. The footsteps behind you were a neighbor.
• They can be fed by our thoughts. A feeling that should pass in minutes can last all day if we keep replaying what caused it.
• Most of us never learned their language. Without words for what we feel, it is hard to know what to do. That is the subject of The Emotion Wheel: How to Name What You Feel.

Understanding why we have emotions doesn’t make difficult ones painless. But it changes the question from “what’s wrong with me?” to “what is this feeling trying to do for me, and is it right this time?”

A small practice

Pick one emotion you had today, even a small one. Ask yourself three questions about it. What did it notice? What did it want me to do? Was it right? You’ll often find the feeling had a point, even if it overstated its case.

For the bigger picture, see How to Understand Your Emotions.