Humans are the only species capable of modulating laughter to communicate complex social intentions, according to a study published in Communications Biology. Researchers from the University of Warwick documented that while all great apes—including chimpanzees, gorillas, bonobos, and orangutans—laugh, they tend to stick with fixed patterns and tempos.
How does human laughter differ from apes?
Humans possess a unique ability to shift the tempo and pattern of their laughter depending on the social context. Chiara De Gregorio, a researcher at the University of Warwick and coauthor of the study, told The New York Times that humans can have a small, polite laugh in front of the Queen of England and a different laugh in a pub with friends. Apes, by contrast, tend to stick with fixed patterns and tempos. The study suggests this vocal control is a key evolutionary precursor to the development of human language.
When tickled, both humans and apes produce laughter in an isochronous rhythm—meaning the “ha” sounds occur at regular, beat-like intervals. This suggests that the physiological roots of laughter are shared across the hominid family tree.
Why is laughter considered a window into evolution?
Laughter serves as a proxy for tracing the evolution of the phonatory-respiratory system, according to the researchers. By recording the vocalizations of 13 young apes, the team found that our closest relatives, chimpanzees and bonobos, exhibit faster laughter tempos than more distant relatives like gorillas and orangutans. This trend indicates an evolutionary trend in vocal flexibility. The researchers argue that this flexibility allows individuals to convey socially relevant information, such as emotional state and intent, beyond the simple signal of “I am having fun.”
What are the limitations of the current research?
The researchers are the first to admit that the study is very small, and its authors acknowledge that further work will need to bear out their findings. The experiment relied on 13 captive apes and four human children. The researchers noted that perhaps children were used because they’re not yet self-conscious enough to change their laugh for an audience.
Pro Tip: Observing Social Cues
If you want to test this in your daily life, pay attention to the “social laugh.” Next time you are in a meeting or a social gathering, note how people modulate their laughter to signal agreement or politeness rather than genuine amusement. This nuanced control is exactly what separates our vocal evolution from that of our primate cousins.
Frequently Asked Questions
Do all apes laugh when they are tickled?
Yes. According to the Communications Biology study, all species of primates, including humans, laughed when tickled.
Why did the study use children instead of adults?
The study recorded the laughter of four children and no adults. Perhaps because they’re not yet self-conscious enough to change their laugh for an audience.
Is laughter unique to primates?
Laughter is a universal form of human non-linguistic vocal expression and, being shared by all extant great apes, offers a valuable proxy for tracing the evolution of vocal control that ultimately enabled language.
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