Smiling and laughing are the natural expressions of human emotions in relationships with others. The cultural norms regarding their expressions, however, vary across cultures. People in some Western cultures, such as the European-American one, commonly use them. People in other cultures, such as Eastern Asians, are more reserved in their expressions of laughter and smile much less frequently (Karandashev, 2021).

The question of research interest is “Why do we need laughter and smiles?”

Researchers most often conduct scientific studies of laughter and smiles in Western cultures, such as England and the USA.

Here is one example of a study that British anthropologist Robin Dunbar and Austrian psychologist Marc Mehu conducted in 2008 (Dunbar & Mehu, 2008). They found that strangers who were talking to each other smiled and laughed more than once every two minutes.

When Do We Laugh and Smile? 

We smile when we’re happy, excited, shy, confused, recognizing someone we don’t know, winning, or losing. We laugh when we are amused, nervous, angry, greeting a puppy, teasing, or just don’t know what to say.

Men and women usually smile and laugh when they are with other people. They intuitively anticipate that others can see their smiles and laughter. And they expect, either implicitly or explicitly, that their smile and laughter will influence other people who see and hear these emotional expressions.

Why Do We Laugh and Smile? An Evolutionary Perspective

Professor of Psychology at the University of Virginia, Adrienne Wood, and her colleagues are investigating how smiling and laughing can be viewed as evolutionarily ancient behaviors conveying a wide range of messages (Wood et al., 2018; 2022). They propose that smiles and laughs can serve three functions:

(1) reward,

(2) convey affiliative intentions,

(3) assert dominance.

The Rewarding Function of Laughter and Smiling

These are the smiles and laughs that make you feel good. They show how happy the smiling and laughing person is. They also thank the other person for making this person happy. It’s nice when people smile and laugh with us, especially when we know it’s because of something we did.

This is why marketing companies put happy faces on ads for everything from car insurance to toilet paper: they want people to think well of their products.

Laughter also makes people feel good, which is why laugh tracks are used in comedies.

The Evolutionary Origins of Smiling and Laughing

These gratifying smiles and laughs could evolve from mammalian “play signals.” The animals’ play signals make it clear that they mean no harm. One can see that in some ways, smiles and laughter serve the same purpose. And these signals are rewarding—they make the recipient feel good. So, they help extend the playful interaction.

The Affiliative Function of Laughter and Smiling

Yet, most smiles and laughter are not rewarding expressions of happiness. This could be our quick, closed-lip expression when greeting a passing stranger or expressing sympathy to a friend. Or, we could use the polite laugh to ease awkward tension in a group meeting.

These expressions are the shadows of those big, happy smiles and laughs. They borrow the message of friendly, harmless intentions from reward signals. Therefore, we may call these smiles and laughs “affiliation signals.” Smiles and laughter, elicited by nervousness, embarrassment, sexual attraction, friendliness, and politeness, all have the common goal of increasing affiliation.

Do All Smiles and Laughter Make People Feel Good?

Some smiles and laughter, however, are far from making the recipients feel good. They can make them feel rather bad.

We all know how it feels when people laugh at us instead of with us. People sometimes tease, mock, make fun of, or criticize someone while smiling and laughing. One may call these smiles and laughter “dominance,” because they show that someone is better than someone else.

At first glance, it seems strange to think that a play signal that means nothing bad could be changed into something not so good. But when people smile and laugh like this, they are saying,

“I think you are completely harmless and not serious.”

There may not be a better way to show that you are in charge than to act like you don’t care about someone.

Many men and women believe that smiling and laughing improve their interpersonal relationships. Others believe they should be more reserved in their emotional expressions and not smile as much. In this regard, people from different cultures may have different explanations and cultural stereotypes.