YMIAFT Chapter 1 Part 6
Standup would be so much easier if I could just tickle you
“If you prick us do we not bleed? If you tickle us do we not laugh?”
~ William Shakespeare
One thing that isn't funny is tickling.
Wait... what? Tickling obviously makes people laugh, doesn't it? How can I say it's not funny? Aren't I now suddenly breaking my own, “if they laugh, it's funny,” rule?
When I say tickling isn't funny, what I mean is that there is no humour being processed in the brain. You see, unlike when someone gets a joke, we can jam someone in a brain scanner and trace the route that tickling goes through from where they're touched to where their brain kick starts the laugh response, about as well as we can trace a pin prick. The path starts somewhere in the somatosensory cortex, which registers the touch sensation, and ends up in the motor cortex, responsible for all body movements, which controls all the vocalizations and actions that combine to form laughter. This is different from understanding and responding to jokes. If I put you in a brain scanner and got you to laugh at jokes, the pathways through your brain are much less distinct.
Scientists have tried to find those pathways, to see how the experience of getting a joke winds it way through the brain, by throwing people into brain scanners and getting them to laugh. Some of the areas within the brain that have been linked to humour are the nucleus accumbens, the medial ventral prefrontal cortex, the bilateral posterior temporal lobes, and many others, with equally crazy names. What's notable about them is only that these attempts to find a part of the brain identifiable as a “humour centre” hasn't produced any consensus. As one researcher, Joseph Moran, said in a study called Neural correlates of humor detection and appreciation, “there’s no standard set of regions that we know are involved in humour.”
The hard evidence of science shows that the brain processes tickling and humour differently. However, they both end up at the same place, laughter, so there has to be at least some relationship between them.
Research has shown that tickling seems to exist in other mammals, like chimpanzees, dogs, and rats. Rats, for example, have been shown to respond to tickling-like touching with a high pitched sound. It's often too high for humans to hear, so it's gone largely unnoticed for a long time. Not to mention that it's not most people's first impulse when they see a rat to tickle it. I think that the purring of domestic cats might also be included. Even though we might not ordinarily categorize scratching behind their ears as “tickling”, and purring doesn't sound like laughter, it's still a sound that is usually elicited by touching. The specifics will naturally vary among species, but the implication remains that the origins of tickling might go back to a common mammalian ancestor. If so, then tickling predated humour, predated language and culture, and even predated us as a species. On the other hand, while we potentially share tickling-like behaviours with other species, humour seems to be exclusive to us. From that chronology, it seems reasonable to suggest that humour evolved within us by repurposing the available mechanisms used in tickling. Just as it's likely that crying to get dust out of our eyes was present in us as a species when we diverged from other simians, and then later it took on the extra purpose of expressing sadness.
Laughing from being tickled and laughing at something humorous are two identifiably different things. Disagree with me and I'll throw you into a brain scanner and tickle you until you cry. Later we'll reconnect tickling with humour by getting more in depth about our evolution. For now, though, to understand why we laugh and what is humorous, we need to set tickling aside, just as we need to do with other conditional factors, like the amount of sincerity in the laughter.