Overview
- The study, published June 25 in Communications Biology, compared 140 laughter bouts from 17 individuals across orangutans, gorillas, bonobos, chimpanzees and four human children to measure timing and rhythm.
- Analysts found laughter in all sampled great apes is isochronous, meaning vocal bursts recur at regular, evenly spaced intervals, and tickle‑induced laughter was the most rhythmically regular.
- The tempo and variability of laughter tracked phylogeny: chimpanzees and bonobos laughed faster than gorillas and orangutans, while humans produced the fastest and most timing‑variable laughs.
- Humans were uniquely able to speed up laughter by context, laughing faster when tickled than during free play, a pattern the authors link to greater vocal flexibility in our lineage.
- Authors interpret the conserved isochrony as evidence that a recognizable laughing rhythm existed in the common hominid ancestor about 15 million years ago but stress the small, captive and archival sample and call for larger wild and diverse recordings to confirm the result.