Years ago, my colleagues and I discovered that observers could determine the nature of a relationship (friends or romantic partners) based on brief snippets of vocal cues, including laughter. But it was only recently that we figured out how people made these judgments. What we found was fascinating and counterintuitive, and only adds to the intriguing nature of laughter because much of what people think they know about laughter is wrong.

Here Are Some Little-Known Laughter Findings

  • Laughter is variable—it may sound like a repetitive vocalization of a consonant,
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    but it can also be a single vocal burst, potentially one that is "unvoiced."
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  • Laughter plays an important role in the dating game, but men and women value it differently. Women value a man's sense of humor, whereas men value a woman who appreciates their sense of humor (through laughter).
  • Laughter has different types—it often communicates positive emotion (such as affiliation or enjoyment), but it can also convey dominance, contempt, or schadenfreude (taking pleasure in somebody else's misfortune).
  • Most laughter occurs in response to comments or situations that are not funny.
  • Speakers laugh more than listeners do.
  • We are not the only species that laughs. As many as 65 species of animals laugh including primates, dolphins, some species of parrots, elephants, rats, and Australian magpies. These last three findings underscore that the primary function of laughter is not about showing humor appreciation, leading to the conclusion that ...
  • Laughter is about social connection. Although laughter is contagious, like mimicry, ingroup status moderates its effects. Specifically, we are more likely to reciprocate the laughter of ingroup members than outgroup members. This means that laughter "tells" others about the closeness of our relationships.

In the last ten years, cognitive scientist Greg Bryant has shed light on the surprising ability of listeners to suss out affiliation based on laughter. Based on brief segments of laughter, listeners across cultures can determine whether laughter is real or fake. More impressive, perhaps, is that even babies as young as five months old can differentiate laughter directed at friends versus strangers. These skills fit with the dual pathway hypothesis, which posits that there are two distinct routes to laughter production, an ancient pathway that emerged from the pant-hoot vocalization of apes and a newer system that is articulated through the speech production system. Authentic laughter reflects genuine enjoyment and emerges from the reptilian core and brain stem. When we developed the capacity for speech, we learned to have precise control over the tongue and the lips, which allows us to modulate the sound of our voices in potentially deceptive ways.

Distinguishing the Laughs of Friends Versus Romantic Partners

My colleagues and I conducted the first set of experiments to determine if listeners can make an even subtler distinction—to differentiate between laughter directed at friends versus romantic partners. Our idea was that individuals in early-stage romantic love (in the first year of their relationship) would be more likely to voice laughter in the speech production system (to alter the way it sounded to their romantic partners). In contrast, laughter emitted during friend conversations would emerge from the more ancient production system. People are more comfortable with friends; these relationships require less intense maintenance and effort, thus we suspected that laughter with them would sound more natural and less forced. In addition, we predicted that the vulnerable stage of early romantic love, due to its tenuous, rollercoaster nature, would leak out through laughter, making laughter with romantic partners sound more submissive and tense.

The laughter from this research was sourced from a previous study in which men and women called a friend and romantic partner while being audio-recorded. In Study 1, based on 52 laughter clips, new listeners successfully differentiated between laughter directed at friends and romantic partners. Study 2 focused on the cues driving this ability; in this study, 58 new listeners judged prototypical friendship laughter as louder, more relaxed, and more natural-sounding than prototypical romantic laughter. Also, romantic laughter was perceived as more feminine-sounding, more baby-like, more submissive, and less pleasant-sounding than laughter directed at friends, which supports our vulnerable love hypothesis. The final study replicated the findings of the first two studies using 252 participants from five unique countries: India, Mexico, Poland, Portugal, and the United States. Importantly, these three studies showed that individuals are able to differentiate between two closely-affiliated relationship types based on a mere one or two seconds of laughter.

This research is important because it underscores that laughter is more nuanced, variable, complex, and socially important than most people believe. Laughter can be used to make others feel better, reinforce ingroup status, convey romantic interest, or show affection, but it can also be used to project status or castigate others. The giggles and guffaws people emit signal to others not only how close they are to one another, but in what way they are close. Listeners use laughter to make impressive and accurate determinations about the nature of social relationships.

For Further Reading

Bryant, G. A., Fessler, D. M. T., Fusaroli, R., Clint, E., Amir, D., Chávez, B., Denton, K. K., Díaz, C., Duran, L. T., Fanćovićová, J., Fux, M., Ginting, E. F., Hasan, Y., Hu, A., Kamble, S. V., Kameda, T., Kuroda, K., Li, N. P., Luberti, F. R., … Zhou, Y. (2018). The perception of spontaneous and volitional laughter across 21 societies. Psychological Science, 29(9), 1515–1525.

Farley, S. D., Carson, D., & Hughes, S. M. (2022). Just seconds of laughter reveals relationship status: Laughter with friends sounds more authentic and less vulnerable than laughter with romantic partners. Journal of Nonverbal Behavior. Share it link:

Provine, R. R. (2001). Laughter: A scientific investigation. Penguin.

Sally Farley is a professor of psychology at The University of Baltimore. Her research falls at the intersection of nonverbal behavior and relationship science. Her colleagues on this project are Deborah Carson, Math and Statistics Coordinator at The University of Baltimore, and Susan Hughes, professor of psychology at Albright College.