YMIAFT Chapter 3 Part 4
Gotta get me some of that
“If you laugh too hard, you cry. And vice versa.”
~ Sid Caesar
The humour network in our brains, if it is a system for assessing commonality, would be a really useful feature for social creatures like humans. Just because it would be useful, though, doesn't mean we'll automatically get it. Personally, I think humans need wings, but I'm not flying. How, then, did the humour network get to be there, and be so ubiquitous in the human brain?
New traits can come along with random mutations, but they are almost always far less exciting than super hero comics would make us believe they are. It's hard to imagine that a robust system like humour, or even a simpler variation, could pop into existence just with some switch in a gene somewhere. It's more likely humour came about through another common way for a species to evolve a new trait, which is for there to be pre-existing features that can be exploited in new ways. The sensation of physical touch leading to pleasure and vocal response seems to be in other mammals as well as us, as mentioned in the first chapter, which would indicate that some kind of proto-tickling mechanism was present in an ancestor so far back in our evolutionary past that it is common to species as distantly related as rats and humans.
Why rats respond with an ultrasonic squeak to a particular kind of touch is beyond me. What any mammal does with their version of touch and response is their business. We also don't know why or how it manifested in our common evolutionary ancestor. However, all those questions are going deeper than this book needs to go. The point is only that evidence supports the fact that before we were even a species, there was some kind of pleasurable vocal response to touch, in some common ancestor previous to rats and people. As other species branched off from that ancestor, that touch and vocal response mechanism diverged into different manifestations, serving different purposes.
It's like how both cats and dogs have tails, but when they swish them from side to side, they have almost opposite meanings. With cats it indicates irritation or that they are about to pounce. With dogs, it generally means they're happy and excited that you just got back home after being out of the house for what seemed like forever. Every animal inherits traits from the species that preceded it, and then takes those features and go their own way with it. It could have turned out that humans would purr when we found something funny, or laugh when scratched behind our ears. We're asking why things are the way they are now because that's the way they turned out, not because they necessarily had to turn out that way.
We now have two essential details in place for the evolution of humour to occur. One is that the physical feature is already there in the form of laughter as a result of tickling, inherited from some mammalian ancestor long ago. The other is that there is pressure to establish commonality among ourselves within groups. Ostracism is bad, commonality is good. The question is, how did these two factors come together?
The answer is revealed in how our brain got to be structured the way it is. Think of it as a stack of blocks, where each block contains a different cognitive function. The process of evolution placed new blocks on top of old ones, so that more advanced parts are higher up than less advanced parts. At least in general. The reality is that as our brains got bigger, our skulls didn't always conveniently expand to match, so as a result, our brains are all squished up inside our skulls with not everything perfectly in order. Nonetheless, it's accurate enough to think of more primitive functions, like sensory perception and motion, as being lower down and toward the back, closer to the spine. Advanced functions, like language, are higher up and near the front of your brain, just behind your forehead.
Way, way back when we were much fuzzier, there was a tickling function, and our brains were physically smaller, not yet having developed all the layers of advanced thinking. The exact purpose of our tickling mechanism at the time is opaque to us now, buried under countless adaptations since, but in some way or another it's monitoring for the right kind of touch, and responding with a vocal response and a feeling of pleasure. All indications are that the right kind of person's touch at the right time felt good, helped you form bonds with those people, and inspired a more or less automatic vocal response to let them know about it so that they could bond back. As humans evolved and added each and every new cognitive development to their brain, there's a need to know with each and every stage of development whether that new cognitive ability separates you from the people you want to bond with, or ingratiates you with them. As our brain expands upwards, with each new layer added onto the stack, it pulls tickling's capacity for bonding along with it. In this way it starts to take something that is much more of a physical response and integrates it with more conceptual situations.
Just like it's easier to build a new house and put in all the electrical wiring where you want it to go than it is to take an old house and retrofit it with modern electrical systems, the humour network is probably more integrated into the newer areas of the brain than the older ones. Certain modules of the brain, for vision and smell and fight or flight reflexes and so on, would have been largely established previous to any tickling mechanism or laugh response. The humour network, once it started developing, could have woven its way into established areas as well, so you could laugh at a colour or smell or being startled. However, it seems likely that the humour network had more opportunity to embed itself deeply into areas of the brain that grew with it. As a result, we are potentially more nuanced and sensitive to humour that appeals to our conscious thought, language, reasoning, and so on.
Why was it that what we can now identify as a “humour network” got pulled along into higher brain layers instead of something else? Why, for example, did it have to be laughter for humour and tears for sadness? It could have gone the other way. Nothing is predetermined in evolution, and had our species zigged instead of zagged in our development, this book would be about why we cry at funny things. It's probably not entirely random, in that tears can go unnoticed and laughter pulls in people who weren't already looking at you, so there may be reasons why one existing trait got repurposed and not another. However, we'll never see the alternate universe that went the other way, so all we can do is consider how it ended up. The tickling response was there, it was a viable option, and that's the one that got taken. The important point is that the humour network grew upward along with our brains, so that the humour network as we know it now was fully established by the time we were starting to pick up pointy sticks for hunting and making our buddies laugh by using them to pick our nose.
This also implies that it was there helping us form social bonds with every step that we took toward developing more consciousness and the ability to think independently from the group. Consider that wolves might not need too many ways of evaluating commonality in thinking because they don't possess the ability to think too differently, to deceive, or to individuate themselves. I'm not saying they have no ability to do those things, just that they don't have enough of them to put their group cohesion at risk. Humans though, even at a mid point of evolution between being simpler apes and fully cognitive, are chock full of potential to deceive and go their own way. Too much ability to deceive each other and no one can be trusted and social bonds get really difficult. The humour network could have helped us stay in groups by mitigating some of the dangers of independent thought. If the humour network formed after we had evolved our fancy frontal lobes, it might have been too late.
Evolution is ridiculously slow. No matter how slow you think it is, it's slower. Which means that much like the rest of our biology that identifies us as modern humans, our humour network probably hasn't changed much since a few hundred thousand years ago, around when scientists generally agree we became the species we are now. We imagine our sense of humour to be way more sophisticated than a caveman, who would probably laugh hysterically at a well timed rock to the head. As far as I can see, though, we still laugh at a well timed rock to the head. Though it's better if we hit a guy in the balls with the rock. And if it's a baby that threw the rock, and we film it and upload it to YouTube, all the better. We still respond to really base humour, we just laugh at other stuff too, and that's probably only because we now have so much other stuff to laugh at. The mechanism of listening for the right synaptic activity doesn't need to be any different to assess the funniness of a rock to the head versus a clever and witty pun, and it almost certainly isn't, not having had the time to change too much anyway.