That Neuroscience Guy - The Neuroscience of Humour

Episode Date: March 20, 2022

Whether it's watching your favourite comedian, or just joking around with your friends, we all experience humour in our daily lives. But why do we laugh so much, and why do we tend to laugh at different things than others? In today's episode of That Neuroscience Guy, we discuss the neuroscience behind our sense of humour, and why laughter is actually good medicine.   

Hi, my name is Olof Krogolsen and I'm a neuroscientist at the University of Victoria. And in my spare time, I'm that neuroscience guy. Welcome to the podcast. Did you hear the one about why the chicken crossed the road? To get to the other side. the road to get to the other side. Okay, so that's not my best joke, but there is a large body of neuroscience research examining the neuroscience of humor. We touched on it briefly in season one during a Q&A episode, but now we're coming back with a full episode and we're going to explore it in depth. On today's episode, the neuroscience of humor. When researchers examine humor, they generally focus on two main subdivisions, practiced versus spontaneous humor. Practiced humor refers to jokes that are memorized in advance

and that are brought out when you need them. Think of a comedian on a stage giving a performance or a joke that you have in your pocket that you tell when you feel the need to be funny. Spontaneous humor is different than that. It refers to the quips that you make in response to something that you see or experience, but that you haven't memorized in advance. You're just generating the humor on the fly.

In terms of spontaneous humor, recent researchers have examined experienced comedians and regular people making comedic responses to presented images while the participants' brains were being scanned in an fMRI scanner. And what they found was super cool. Basically, in people that had comedic experience, there was a decreased activation in the prefrontal cortex relative to the regular participants. In other words, the part of the brain responsible for executive control or deliberate thought

was not as active in experienced comedians. However, the researchers also found increased activation in the temporal cortex of these experienced comedians, and specifically the temporal association areas of these people relative to regular participants. But what does it mean? We haven't really talked a lot about association areas, but the general idea is that the temporal association area is a place where ideas are linked together naturally. So the experienced comedians had an easier time linking the pictures they were viewing to a funny quip or comment.

And this is due to literally their experience. And another sign of this ease is the reduced activity that was seen in the expert comedians. However, making the quips was not as easy for the less experienced comedians, so that was seen as less activity in the temporal association areas, and more activity in the prefrontal cortex which was trying to guide them effectively and control what was happening. So if you want to be spontaneously funny, you need to practice. Makes sense when you really think about it. And this leads us naturally into well practiced humor.

Obviously the brain areas I just mentioned are a part of what is happening there as well. The prefrontal cortex guiding the process, and the temporal association areas being where jokes are processed and most likely stored. Within the prefrontal cortex, the actual region that people are focusing on in these studies that I've mentioned so far is the medial prefrontal cortex, otherwise known as the MPFC. The medial prefrontal cortex is a brain region that is activated when any type of creative person is generating their art, jazz, improv, drawing, or writing poetry. Researchers also see activity in other regions of the brain, regions associated with memory

formation. That makes sense, because you're trying to memorize a joke, right? You're developing something that you want to store. So in the early stages, you see activity in the hippocampus, and that's due to its role in binding memories together, which we talked about in a previous episode. And you also see activation in areas like the amygdala, our old friend. And that's activated as part of the emotional response to the humor of the joke. And even the motor system comes into play as we have to control the tone and pitch of our voice. So those are speech production areas like Broca's area. And you also, even

the way you're standing, the body language associated with the joke itself. So, you know, when you're generating humor, basically a lot of the brain is activated and as you are going to find out, there are even other parts doing other things. But first let's just talk about another issue, which is what actually makes something funny and why does our brain think of it as being funny? Why do we laugh in other words? Well, the most common explanation involves the concept of mismatches. When there is a difference in what one might expect and something unexpected, which is

the joke. So this theory also explains why hearing the same joke over and over again eventually becomes not funny, because the mismatch goes away, because once you know what the outcome is, you're not going to find it as funny. And this mismatch idea also drives a lot of other ideas about why humans are so obsessed with constantly seeking out new information, in whatever form they prefer, whether it's social media, the newspaper, television, or just talking to people. Because if you see the same thing over and over again, your brain literally gets bored with it, so you're

trying to draw out new material. Now this of course is subject to individual differences, but a lot of us are in that space where we're constantly craving new things to stimulate us. The mismatch theory is interesting, and it's probably the right theory, but it doesn't explain why I can keep watching Dumb and Dumber over and over again and still laugh every single time. Now what's going on in the brain? We've talked about some of the brain regions but let's add some more to the picture as well. Well of course you see activation in visual areas of the brain as you process a visual scene. So say

you're watching a funny movie and that would be the occipital and the temporal cortex which we talked about a lot in season one we talked about the ventral visual stream. And you also see activation and language areas of the brain in the superior temporal cortex which we already mentioned and that's as you hear the joke but the same place where the joke is created is where it's processed as well but of course we need some language areas like Wernicke's area which helps us translate speech and you also see activation in the amygdala. Now you might come to think that I say the amygdala in every episode, but I want to just remind you that anytime there's an emotional

content, you're probably going to see the amygdala doing something. And jokes have emotional content. They make us laugh, and that's a form of an emotion. So you see activity in the amygdala. And you also see activity in the midbrain dopamine system. And that's encoding reward, because jokes are rewarding in principle, and it also encodes violations of expectancy, the mismatch in a sense. And we talked a lot about the dopamine system in season one when I was talking about learning, but in brief, recent theories propose that phasic changes in the firing rate of dopamine-produ producing neurons increase and decrease briefly, and that's what's meant by a phasic change, and that's when the unexpected outcome occurs.

Now a lot of these brain regions we have mentioned before, but why is something actually funny? Well it's tied to the relative response in all these brain regions, their relative contributions to the whole pattern of brain activity. And indeed, humor and us laughing as a result is just a unique pattern of brain activity, just as other brain states are, such as depression and happiness and sadness. And of course, finally, there are individual differences. What some people find funny, others do not,

and that is simply because these individuals are processing and experiencing the same scene a little bit differently from us. It's worth noting that there's another theory about humor which I mentioned in the previous episode, which has been put forward by other researchers. In their work, they propose laughter is triggered as a form of a stress response, essentially. Now, from an evolutionary perspective perspective one can imagine one of our ancestors in a threatening and stressful position. Perhaps the proverbial caveman being chased by a saber-toothed tiger. This would be stressful of course and once the stress is removed, say the caveman somehow escapes, then the release

of the stress triggers laughter. It's just a natural reaction to the stress being disposed of. This, of course, works for certain kinds of jokes where there is a bit of a build-up before the punchline. This would be the modern analog to the caveman's experience, and we laugh as the stress is released. Like I said, however, this is only a great explanation for certain types of humor, and it's not as widely accepted as the mismatch theory. With that said, there is some good neuroscientific evidence for it. Researchers have found that experiencing humor leads to increased activation in the sympathetic nervous system, which is your sort of your base fight or flight response, activating the adrenal glands, and also some

processing in the brainstem. Researchers have also found that humor leads to activation of the hypothalamic pituitary adrenal cortical axis, which one way to think about it is just a releasing of chemicals into the bloodstream. And this is associated with our response to stress. So in other words, humor leads to activation of the sympathetic nervous system, which is a part of the fight or flight response, and also in brain regions that are associated with a response to stress. And that kind of leads some support to the evolutionary perspective theory.

Interestingly enough, having a good sense of humor is also being associated with health benefits. In one now-famous study, 65,000 Norwegians were surveyed, and the researchers found that people who rated their personal health as good or great also reported having a bigger sense of humor than other participants. And these people were also less healthy. Now it's a very large study, it's not the only study that shows this relationship. shows this relationship. In another study, researchers examined possible health benefits from individual differences in sense of humor among a sample of patients who had been diagnosed with kidney failure and who were receiving regular dialysis. This study was carried over two years. After controlling for sex, age, education, and disease severity measures, sense of humor was found to significantly predict quality of life and even the likelihood

of survival from the beginning of the study to the end of the study. And researchers have even also found that having a better sense of humor is associated with a heightened immune response and also increased pain tolerance. So I guess the take home lesson is that it's very good to laugh if it might even save your life one day. Okay, another poor joke, my apologies. Well, that is all I have for the neuroscience of humor. In summary, you see activation in numerous brain regions, including the prefrontal cortex,

and specifically the medial prefrontal cortex, the temporal cortex, the amygdala, the hippocampus, and even the motor system. You'll also see activation in midbrain systems like the dopamine system and the sympathetic nervous system. So I think the key message is that our experience of humor reflects a unique pattern of brain activity. But never forget, that's true for any other brain state. Now don't forget, the website is up, thatneuroscienceguy.com. There you'll find links to Patreon where you can support the show if you wish. Never forget that just a one dollar donation a month could make a big difference.

You can also find links to our Etsy store where we have a bit of merch for sale with more coming. I'm just working on a t-shirt design right now for our second t-shirt to be released. And we're also going to be releasing That Neuroscience Girl shirts because, hey, to be released. And we're also going to be releasing That Neuroscience Girl shirts, because, hey, anyone can be a neuroscientist. On the website, we also have a link to our YouTube channel, That Neuroscience Guy, my blog, which is on my personal page, and of course, my Twitter feed, at That Neuroscience Guy. Please follow me. It makes a big difference. And also, please subscribe to the podcast. Thank you for listening, and I'll see you on Wednesday for another brief neuroscience bite. My name is Olive Kregolson, and I am that neuroscience guy. Thanks for listening.