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Laughter is ubiquitous across human cultures. It’s associated with joy, fun, playfulness and has great importance in our social life. But, for centuries the question of its origin and function has fascinated scientists and philosophers alike. Now, Philosophical Transactions of the Royal Society B, collects fresh evidence from biology, neuroscience and psychology to challenge longstanding assumptions on how and when laughter evolved.
The special issue was guest-edited by Fausto Caruana from Parma University and the CNR Institute of Neuroscience, Elisabetta Palagi from Pisa University, and Frans de Waal from Emory University, in the United States.
“The philosophical tradition inextricably links laughter with humour” says Caruana, “but we think this is barely scratching the surface of a complex phenomenon”. Palagi adds that “there is an anthropocentric perspective on laughter that dismisses a large body of studies about it in other animals”.
In their introductory article1, Caruana and colleagues review recent evidence that challenges the idea that laughter is a uniquely human phenomenon. They describe work2 by the late psychologist Jaak Panksepp ,who discovered vocal patterns in rats that may have evolutionary relationships to primates’ laughter. “Panksepp’s work was essential to gain momentum to shift the anthropocentric paradigm” says Palagi.
Insights on the evolutionary roots of laughter come from neuroscience too. Caruana notes that evidence is accumulating about similarities in rats and hominids neural circuits that underpin playful behaviours and vocalisations3.
Palagi also cites studies by Robert Provine, a neurologist and psychologist at the University of Maryland, who emphasised the communicative and social significance of laughter. His studies showed that laughter is about 30 times more frequent in social than solitary situations, underlining its significance, for example to better contextualize verbal and nonverbal conversation, or strengthening group bonds thanks to shared positive emotions. Recent neuroscience studies, including some by Caruana, suggest that the contagious nature of laughter may be mediated by specific neural circuits involving mirror neurons.
Such findings suggest that laughter-like behaviour may have been present in the common ancestors of different mammals, and that it may predate humour.
