Overview
- The peer‑reviewed study, published June 25, 2026, analyzed 140 laughter bouts from 17 individuals covering all five great ape lineages and humans to compare timing and rhythm.
- Across species the bursts of laughter showed isochrony, meaning the sounds occurred at regular, evenly spaced intervals, a pattern the authors trace back to the last common ancestor about 15 million years ago.
- Human laughter differed by being faster, more variable in timing, and the only one to change tempo with context, with tickle‑induced laughter showing the strongest regularity compared with freer play laughter.
- The authors stress limits to the findings because samples were small, mostly from captive or archival recordings, and they call for larger, wild and age‑diverse datasets to test species‑level claims.
- If confirmed by broader data, the results give researchers a new behavioral window on how gradual gains in voluntary vocal control may have paved the way for speech and for richer social signaling in people.