YMIAFT Chapter 2 Part 2
The laugh centre
“Does the brain control you or are you controlling the brain?”
~ Karl Pilkington
Stephen Colbert, on his television show The Colbert Report, once asked Steven Pinker, a cognitive scientist who writes lots of popular books about the mind, to summarize how the brain works in five words. “Brain cells fire in patterns,” was Dr Pinker's response. It'd be great if we could just leave it at that, but to see where the humour is happening, we'll need to know a little more than just five words.
At least one part of how humour works in the brain, the laughter part, is reasonably well understood. Laughter is a physiological response driven by identifiable modules in the brain that can be observed using a brain scanner. Laughter itself is a cluster of different actions, including most obviously the spontaneous vocalizations we know and love, but also other associated actions like spasms, the release of pleasurable chemicals in the brain, and an increased heart rate. All of which will vary in intensity between individuals, but are consistent enough, especially the vocal component, that there aren't really any big surprises about what laughter is and where it happens in the brain. By and large, the parts of your brain that regulate those laughter outputs are within the motor cortex, which is the section of your brain that controls all of your movements. Whether you consciously decide to move your hand for a deliberate purpose, or unconsciously and reflexively pull it back from a pin prick, the signal to move your hand will go through the motor cortex. Similarly, when you are laughing, each action that combines to form laughter is being driven by various subsections within the motor cortex. For the purpose of understanding humour, it's good enough to think of all the associated modules as being one thing, a “laugh centre”. In the process of humour, by the time the activity in your brain has reached the motor cortex, your brain is just generating output.
Finding where the humour happens in the brain before the laughter is the tricky part, because unlike tickling, it's hard to create a consistent input so that you know where to start tracking the sequence of activity. Sure, I can tell you some verbal jokes or maybe show you funny pictures while you're strapped into a high tech scanner. But how can I reliably reproduce for you the experience of how funny it was that time your friend accidentally revealed an embarrassing secret? Or when you laughed spontaneously because of a memory unprompted by anything you were particularly aware of? Or countless variations of “you had to be there” moments? Lab conditions restrict the kinds of potential humour we can test, leading to results that very likely say less about humour and more about the constraints of the experiments.
Even within those narrow confines of testing only certain types of jokes in labs, different studies offer different proposals of where humour happens, so we still don't see any one part of the brain light up consistently enough to be a potential “humour centre”. That being the case, I think we're justified in wondering if there's another approach we can take to search for humour that doesn't rely on a modular model of the brain. Fortunately, there are other ways of looking at how the mind operates that are more consistent with the idea that anything we can think of in almost any part of our brain can be funny. Humour isn't just some switch somewhere in our brain that is simply toggled on or off with the right inputs, it's our whole mind that has a sense of humour.