I discuss here the following article:
Gervais, M. and D. S. Wilson (2005). The evolution and functions of laughter and humor: A synthetic approach. Quarterly Review of Biology, 80, 395-430.
I like this article and think it is important. Gervais and Wilson review extensive evidence for the evolution of laughter and humor, looking at physiological evidence, neurological evidence, and psychological evidence. While it is not the centerpiece of their paper, they include Wilson's "multilevel selection theory" and the observations that many of the evolutionary benefits of laughter and humor accrue to groups rather than individuals. While in general I agree with them, I think that they do not place enough weight on the social function of humor in adjusting group status hierarchies, which indicates an even larger group-level benefit. In their speculation about how laughter and humor evolved, they do not fully embrace the group-level selection pressure as the primary driving force. I would be willing to go that far.
Gervais and Wilson open their investigation with empirical evidence that laughter is an evolved instinct. Cross-cultural studies show the common feature eliciting Duchenne laughter is incongruity and unexpectedness. This laughter usually involves both a playful frame and a second interpretation of the event, which they call "an alternate type of intelligibility" (398). Here is a quote: "There is thus an intuitive family resemblance among the different proximate causes of Duchenne laughter, such that they can be characterized as sharing a single form or structure: a sudden unexpected change in events that is perceived to be at once not serious and in a social context—that is, nonserious social incongruity" (NSI) (399). NSI includes protohumor such as tickling, play, physical mishaps. This conclusion supports both the incongruity aspect and the social aspect of all humor.
I do not disagree with that view. In fact, the more I study the issue, the closer my own views move toward this conclusion. Back in February, 2018, the sound bite version of my theory of humor was "incongruity plus disparagement." Now, my theory is roughly "incongruity and social / emotional aspects often in a playful context, and the social is often disparagement. The emotions are often incongruous emotions; the motive for producing the humor is often a social function." Not exactly a sound bite. But it can be reduced to a true sound bite: "incongruity plus social." Or Gervais and Wilson's phrase "nonserious social incongruity."
The reason for my focus on disparagement is based on social psychology. The human social environment includes built-in but dynamic status hierarchies. A serious challenge to the status hierarchy can include violence and dehumanization and may cause a social group to split. The fact that most laughter is in a nonserious environment means that there is no direct and violent dominance struggle going on. A playful individual is usually one who is submissive. Because some humor can disparage its target to the point of terrorizing the target or inciting violence, I think that not all humor can be called nonserious, so I prefer my "incongruity plus social."
Gervais and Wilson offer a list of the many positive social functions of humor and laughter (404), including the reduction of in-group aggression, which I consider of huge group-level benefit. They note that laughter is a social lubricant, increasing in-group feelings, etc.
Gervais and Wilson discuss the contagious nature of laughter in relation to mirror neurons and the positive psychology of mitigating tension and building social bonds. They conclude, "Duchenne laughter is essentially a medium for emotional contagion operating through an intersubjective mirror system" (423). But they ignore that the content of much that is humorous has the effect of lowering social status.
They also discuss evolutionary psychology. The central question from this perspective is: why is it adaptive in the presence of NSI to elicit play from an individual? They bring in Wilson's multilevel selection theory. The social bonding benefits of laughter and play accrue to the group level. Laughter incurs low costs for promoting group beneficial behavior.
They offer hypotheses about the origins of laughter, suggesting that laughter developed before language. Reducing stress on the savannah, humor might have been an ersatz grooming activity. Dunbar hypothesized that language was an ersatz grooming behavior, but laughter fits the profile better than language. As the brain developed more sophistication, the positive emotion might become decontextualized from actual play and tickling.
Gervais and Wilson argue that there is a benefit to the stress relief of signaling that the group is in a safe situation. They see the status hierarchy functions of laughter coming late in human evolution. Joyous Duchenne laughter came first; it was then co-opted for hierarchy maintenance by non-Duchenne laughter (418). I disagree with them here. I believe that, for humans, one of the biggest dangers and sources of anxiety is being on the business end of the social hierarchy. So the status deflation of disparagement humor is a huge emotional relief. So humor whose social function is status lowering can be genuine, Duchenne laughter.
In short, I think this is an important paper for pulling together the many threads of evidence in the biological and psychological literature in order to analyze the evolution of laughter and humor. I think that they could have gone further with the group-level benefits, specifically the social function of adjusting status hierarchies, which should have been a major activity as humans evolved into an species capable of altruism due to group-level selection pressures. I think that group-level selection could be the primary driver of the evolution of humor from primitive pant-hoots of primates during mock aggression.
