The Rhythm of Laughter: A 15-Million-Year-Old Inheritance
A new study published in Communications Biology on June 25 reveals that laughter—whether from a tickled chimpanzee or a human toddler—shares a surprisingly consistent rhythmic beat.
Researchers analyzed 140 laughter sequences from orangutans, gorillas, bonobos, chimpanzees, and human children aged six months to seven years. Their findings show that all species produce laughter with evenly spaced intervals between successive sounds, creating a stable, rhythmic pattern.
"These regular rhythms reflect nuanced vocal motor control inherited from a common ancestor 15 million years ago."
Physical Movement Changes the Beat
The study noted one key variation: laughter during social play showed more variability in its rhythm. This is attributed to the physical movements involved in roughhousing, which directly affect breathing patterns.
Implications for Vocal Control
Simon Townsend, a primate communication researcher at the University of Zurich, confirmed that the findings align with growing evidence that great apes possess far more vocal control than previously assumed. This challenges older theories that non-human primates had limited ability to modulate their vocalizations.
The discovery of a shared rhythmic structure suggests that the neural and physiological foundations for controlled, rhythmic vocalization were already present in the last common ancestor of humans and great apes, a species that lived approximately 15 million years ago.