Although the connection might seem unexpected, looking deeper into the intricacies of laughter offers a rare glimpse at the origins of speech itself.\u00a0<\/p>\n
Laughter in great apes<\/a> and humans<\/a> is inherently repetitive and cyclic \u2013 the well-known\u00a0ha-ha-ha-ha. By studying the subtle variations in how that rhythm is timed and structured across different species<\/a>, scientists can learn how breathing, sound-making and vocal control \u2013 all important building blocks of speech \u2013 have evolved over time.\u00a0<\/p>\n All major branches of the Hominidae family have evolved unique ways of communicating through sound, shaped by their specific needs and circumstances. The one remaining connection is laughter \u2013 we share it with all great apes (chimpanzees<\/a>, bonobos<\/a>, gorillas<\/a>, orangutans<\/a>). But until now, little was known about its defining feature: rhythm.\u00a0<\/p>\n In a new\u00a0study published in the journal\u00a0Communications Biology<\/a>, researchers analysed recordings of spontaneous laughter from four orangutans, two gorillas, three bonobos, four chimpanzees and four humans. Across 140 laughter sequences, they found all species\u2019 laughter follows the same general pattern: evenly-spaced rhythmic intervals between successive sounds.\u00a0<\/p>\n A bonobo laugh. Credit: Marina Davila Ross<\/p>\n \u201cHow did humans evolve the remarkable ability to speak? Speech leaves no fossils<\/a>, and complex language exists only in our own species. But we’ve found a 15-million-year-old clue in an unexpected place: our laughter,\u201d says Chiara De Gregorio, an honorary research associate at the University of Warwick.<\/p>\n \u201cUnlike speech, laughter is shared by all living great apes. By comparing how different species laugh, we can see that a basic rhythmic structure has remained unchanged since our last common ancestor. That’s extraordinary.\u201d<\/p>\n