Appliance of Science: Why do we laugh?

Naomi is a science communicator and mother to three inquisitive children. She can be found at


Science has a branch of research dedicated to the study of laughter. It is called gelotology. Gelotologists have a few theories as to why we laugh; it is likely we do so in response to certain social signals and to strengthen social bonds and connections.

It can be a very effective form of communication, from the short chuckle to the full-on, belly-shaking laugh. Although the sounds we make through laughter are considered very basic and primitive, the act of social laughter can be a very complex, cognitive process.

Certain responses (such as the fight/flight mechanism) are temporarily switched off for laughter to occur. Therefore, laughing in a social groups might show that you are comfortable and trusting in their company.


Laughter is not the same as humour. It is a physiological response to a stimulus, usually involving brain-processing, sound-production, and some form of physical movement.

There are many types of laughter, but they are often categorised into two main groups: complex social laughter and laughter in response to a basic physical stimulus, like tickling.

Tickle-response laughter might be millions of years old; it is associated with play and happiness, and even though it is a more primitive form of laughter, it is associated with increased social intelligence.


There are many parts of the brain involved in laughter. Areas involved in emotional and social responses, such as the frontal lobe and certain parts of the limbic system, are activated as we interpret the laughter of others, and trigger our own response. The amygdala and hippocampus are thought to control the emotional-response element of laughter. The hypothalamus has been associated with deep, uncontrollable laughter.

The left and right hemispheres of the brain seem to interpret different aspects of humour.

As laughter involves emotional, cognitive, and basic motor responses it is little wonder that so many different regions of the brain are involved.


Laughter can have a number of health benefits, from reducing our risk of heart disease to boosting our immune system.

Laughter switches off the production of stress hormones, inhibiting the stress response.

Laughter can also trigger a release of mood-boosting hormones into the body, helping to maintain a healthy emotional state.


Sometimes, the processes to make or interpret laughter go awry. Gelotophobia, for example, is the fear of being laughed at. Sufferers seem to lack the ability to determine good laughter from bad. They worry that all laughter is directed at them in a negative way.


Laughter is universal; it is the one emotional response that can be recognised across different cultures. Laughter is not just a human reaction; it has been documented in other primates and has even been recorded in rats, opening up the possibility that laughter may be found in other mammals, too; some studies suggest that laughter has been observed in dolphins, dogs, and some birds.

Laughter has even made its way into the world of artificial intelligence. In order to further humanise robots, some are now being programmed to laugh appropriately and to express and interpret humour.

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