Photo credit: Zac Mills, the Wildlife Collective
When orangutans are tickled, they produce an evenly spaced, rhythmic laugh that mirrors humans. In fact, all great ape species share this regular, timed laughter rhythm – and have done so for at least 15 million years. This means that human laughter did not emerge independently; its underlying, rhythmic beat was already present in our last common ancestor.
In a new study, researchers analysed recordings of four orangutans, two gorillas, three bonobos, four chimpanzees, and four humans during tickling and play. They discovered that all species laugh isochronously when tickled. This means that the intervals between laugh bursts followed a regular, evenly timed “ha-ha-ha” pattern.
However, human laughter has evolved to become faster, variable, and more context specific. Humans can change the speed and rhythm of laughter depending on the social situation. For example, a polite chuckle in a meeting is very different to a loud cackle with friends. In this way, laughter has evolved to communicate our emotions and intentions.
Studying subtle variations in ape laughter reveals how human ancestors evolved vocal timing – paving the way for complex speech and language. Remarkably, these findings suggest that the basic rhythm of laughter has remained recognisable and unchanged for at least 15 million years.
That is pretty extraordinary!
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