The real reasons we laugh and what different types of laughter mean

Two senior woman in launderettes, laughing, portrait

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“WHILE there is infection in disease and sorrow, there is nothing in the world so irresistibly contagious as laughter and good-humour.” So wrote Charles Dickens in A Christmas Carol. He was in London in the 1840s, but these words ring true in any time or place. Laughter is one of humanity’s few universal traits. Even in the time of covid-19, many people have found that a good chuckle has helped them cope with the stresses, uncertainties and interminable lockdowns.

It is surprising, then, that psychologists and neuroscientists were once reluctant to devote serious attention to laughter, with many believing expressions of mirth to be less important than those of unhappiness or despair. “Psychology still has a lot of catching up to do to balance out what is known about negative emotions with positive ones,” says Gina Mireault at Northern Vermont University.

This has been science’s loss because recent results reveal that there is far more to laughter than you might think. Beyond the obvious connection with humour, it offers some truly profound insights into the nature of our relationships and the state of our health. The study of infant giggles may even help us understand how we develop our sense of self and the ability to read the minds of others. What’s more, laughter turns out to be surprisingly common in other species.

Non-human animals aren’t known for their sharp wits, but many do engage in play, often producing characteristic sounds to signal that their behaviour is friendly rather than aggressive. According to a review by Sasha Winkler and Gregory Bryant at the University of California, Los …