Laughter is nearly as mysterious as it is ubiquitous.

One might laugh at any kind of joke made by another person, any sort of regular comment made by a friend, something said on television, something on the Internet. But did you know that in Dr. Robert Provine’s study of laughter, only 10-20% of occurrences of laughter were in response to something overtly funny? That the presence of other people makes one far more likely to laugh (Douglas, et al., 2010)?

The field of humor, and the subfield of laughter in particular is not fundamentally understood. There is an International Society for Humor Studies, which has an entire journal (International Journal of Humor Research) dedicated to the study of humor as an “important and universal human faculty.” This journal covers topics from lawyers’ use of humor to differing ways that humor is used across gender lines to the 1962 Tanganyika laughter epidemic (see sidebar). Although this speaks to the ubiquity of humor, we still have no answers to the $64,000 questions: how does laughter affect our brain? Why, biologically, do we laugh?

The 1962 Tanganyika Laughter Epidemic

The epidemic was an occurrence of mass psychogenic illness. It started in an all-girls school when a few girls began to laugh uncontrollably for hours at a time (up to 16 days). The laughter was so “contagious” that almost 2/3 of the school caught the bug, and the school was forced to close temporarily. The girls, upon returning home, spread the bouts of laughter to their families, and the pandemic spread across the Tanganyikan countryside, lasting for months. Hempelmann argues that the laughter was not humorous but rather caused by stress resulting from circumstances in the country, and was a “positive” symptom of a disease with very negative effects. For more information, see Hempelmann.

Crucial to our inquiry is the knowledge that laughter is not a solely human phenomenon. When apes pant, this is biologically analogous to laughing (Martin 2007; Laursen 2009). So are behaviors exhibited by other primates, by dogs, and even by rats (Tierney 2007). I personally would not recommend touching any critters on the New York City subway, but if you happen to own a rat you can experiment by tickling him. While rats do not laugh on frequencies that we can hear, they can easily be detected by ultrasound. Since humans and rats laugh in an analogous way, scientists can conclude that the common ancestor of humans and rats must have laughed. This species lived 75 million years ago — so there was laughter in the time of the dinosaurs! (Onion 2005)

Of course, this species is far too distant for us to understand. What can we know about life in the time of the Tyrannosaurus Rex and Velociraptors? Evidently, the approach of trying to understand the biological origins from laughter and humor from this ancestor species is futile. How, then, are we to understand how we ever evolved to laugh? Laughing as a response to tickling, even a joke, seems arbitrary; we are hard pressed to explain humor.

Rather than attempting to derive reasons for laughter from the past, we can look at what laughter does to us in the present to attempt to explain why we grew to acquire it. There is no clear explanation for how tickling helps us, so let’s set aside tickling as a nervous system anomaly for now and look into other manifestations of laughter, and the utility of laughter in species today.

Laughter and humor both serve as forms of communication in both humans and animals.

Laughter and humor serve as forms of communication in both humans and animals. Why, one asks, do we need laughter to communicate, given our highly advanced vocal skills? True, in humans there are ample ways to communicate without laughter, but not so in other animals. Indeed, laughter manifests itself differently in other animals because they are not vested with the ability to speak (Onion 2005). This suggests that laughter was a way to communicate in our pre-vocal ancestors. Laughter is an evolutionarily developing form of communication – evolutionarily present before the ability to speak.

Of course, laughter can help convey the latest funny joke or story. But this is not the full meaning of the word “communicate.” Rather than merely communicating trivial matters, laughter can help us communicate more of the essence of life.

For example, laughter is used differently by men and women. A man generally courts women who laugh at his jokes, while a woman often desires a man who can make her laugh. In a relationship, though, it is often helpful for women to laugh to eliminate tension. Even though we might see laughter as merely jocular, then, or humorous on the surface, laughter is a representative of much deeper, more meaningful phenomena (Nicholson 2008).

It is clear that humor is a short-term stress reliever on the brain. Some theories claim that humor is the result when a mildly tense situation is relieved (Smuts 2011). In this scheme, humor is soothing in the short-term. When you stretch your arm and then release it, it feels good like this model of humor. But we have seen that humor is representative of something deeper, something with no analogue in muscles.

All of the creatures that laugh today do have commonalities. All of us, besides being social animals, are small animals. We conquer and live not by strength of body but by strength of mind. Yet perhaps this strength of mind causes us to make realizations: just how tenuous the thread we hang on to really is. Strong as we are, we are still far weaker than our environments. Far more than the lion or the bear or the eagle can appreciate, it’s a big place out there and we are small.

In base, then, we are insecure. Laughter is a tool that we can use to conquer that insecurity. Rather than building a superficial sense of soothing, like you might get from stretching your arm, the biological “reason” we have laughter – the “reason” it developed at first, and carried on for the 75 million years ensuing, laughter is a more deep tool to soothe that insecurity.

Perhaps this is why laughter more frequently happens in rather innocuous situations – in response to statements as commonplace as, “Where have you been?” or, “It was nice meeting you” (Onion 2005). Although we can use laughter to depose the tension resulting from a mildly threatening situation, we can also use laughter to destroy the tension that builds up from the mildly threatening situation that is simply the place that we are in. Everything that we do reflects our insecure place in the world, and this causes the tension that can be released by laughing.

The tension of insecurity can also be alleviated by associating with other people. This can help to explain why people are more likely to laugh when with others, or why you can’t laugh when you tickle yourself. Associating with yourself on a deep level is nice, but your brain is already hardwired to know that you yourself are there. Thus, we can understand where laughter came from, and why we inherited the biology over 75 million years of evolution: by associating on a deep level with other members of the same species, perhaps by laughing, our ancestors, and we still today, continually come to understand that we are not so alone: that the world is less large and dangerous than we think.

Works Cited

Douglas, Kate, Robson, David, Cox, Trevor (2010). “Laughter, the best medicine,” New Scientist, Vol. 207, Issue 2769.

Hempelmann, Christian (2007). “The laughter of the 1962 Tanganyika ‘laughter epidemic,’” International Journal of Humor Research, 1 January.

Laursen, Lucas (2009). “Human-ape links heard in laughter,” Nature Online, 4 June, http://www.nature.com/news/2009/090604/full/news.2009.541.html.

Martin, Rod (2007). The psychology of humor: an integrative approach (Burlington: Elsevier).

Nicholson, Christie (2008). “The Humor Gap: Men and Women See Laughter Differently in Romance,” Scientific American, 10 April.

Onion, Amanda (2005). “Studies Show Rats Enjoy Tickling,” ABC News, 31 March, http://abcnews.go.com/Technology/story?id=626264&page=1>.

Smuts, Aaron (2011). “Humor,” Internet Encyclopedia of Philosophy, 12 April, accessed 31 May 2011, http://www.iep.utm.edu/humor/.

Tierney, John (2007). “What Happens When You Tickle A Lab Rat? See for Yourself,” New York Times, 18 March. http://tierneylab.blogs.nytimes.com/2007/03/18/what-happens-when-you-tickle-a-rat-see-for-yourself/.