A study conducted by researchers at the University of Warwick shows that humans, chimpanzees, bonobos, gorillas, and orangutans all share the same basic laughter rhythm. This regular rhythm, with evenly spaced intervals between sounds, is thought to have been inherited from a common ancestor that lived at least 15 million years ago. A discovery that transforms our understanding of the evolution of speech in humans.
Until now, we didn't know how our laughter evolved from our distant cousins. By analyzing 140 recorded laughter sequences from four orangutans, two gorillas, three bonobos, four chimpanzees, and four humans, the scientists found a common pattern: all produce laughter with regular rhythms. This result indicates that the basic rhythmic structure was already present in our last common ancestor, around 15 million years ago.
Unsplash illustration image While the fundamental rhythm of laughter has remained unchanged, human laughter has gained speed and diversity. Humans are the only ones able to modulate their laughter according to circumstances: an uncontrollable laugh when tickled differs from a polite laugh in a meeting, a nervous laugh after a mistake, or a contagious laugh among friends. This flexibility, absent in other great apes, shows that humans have developed conscious control over their vocalizations.
This ability to control the rhythm of laughter is thought to be a key step toward acquiring spoken language. The researchers propose that our ancestors gradually gained mastery over the timing and form of their laughter bursts. An advanced vocal control that constitutes one of the foundations of speech. Laughter does not leave fossils, but its comparative study offers a unique view of our vocal past.
The Warwick team emphasizes that the evolution of human vocal control did not happen abruptly. The results indicate a continuity over several million years, with modulation abilities gradually refining. The laughter of modern great apes still bears traces of this long journey, like a sonic echo of our evolutionary history. Humans would therefore not be the only ones to possess rhythmic predispositions for language.
This study, published in the journal
Communications Biology, could help understand how speech emerged. By listening to the laughter of our closest relatives, scientists hope to trace the vocal transformations that led to the appearance of modern humans. Laughter, far more than a mere emotional expression, becomes a research tool for exploring the origins of our language.