Category: laughter

This week in class we’re going to be discussing emotion. The interesting thing is, when I prepared this course years ago, most of the resources I used focused on so-called negative emotions, such as fear, and anger and aggression. As we all know, Yoda felt that fear and anger were paths to the dark side of the force.

I used the term “so-called” because I don’t believe fear and anger or aggression, in and of themselves, are negative.  All our emotional responses, including fear and anger, evolved for a reason, and when you think about it, they evolved for very good reasons. Fear protects us from danger. Imagine not feeling afraid of that fire racing through the forest threatening your life, or that saber-toothed tiger bearing down on you. Anger, and perhaps aggression, are emotions of possession; we experience them when we perceive that something that we value has been taken from us. In an evolutionary framework, this is also a good thing. So much about survival and reproduction centers on resources. Access to food, access to suitable mates, both of these are vitally important things that must be protected, defended, and yes, reclaimed when lost, because they improve our reproductive success. A species that just let’s others take all their important resources is one that won’t be around very long.

So, in my opinion, Yoda was wrong about a great many things.  (And I really wanted to put that clip from “Return of the Jedi” here, but I couldn’t find it on YouTube).

It isn’t much of a stretch to understand why these emotions evolved in the first place, and the value they actually have in the grand scheme of things. But this blog series is about laughter, so lets focus on that for a bit. I’ve already talked about the social bonding function that laughter plays, which is why it’s important. We’re also not entirely sure what parts of the brain are involved in laughter, but we are beginning to image brains in such a way that we can tell if a person is generally happy or generally sad.

It seems to me that the dopaminergic system is probably a major player. Laughter is accompanied by (or produced by?) positive affect. I think it’s pretty safe to say that other people are most often the cause of our laughter. So a release of dopamine is our reward for sharing a laugh, or engaging in some kind of socially-mediated laughter, like those found in conversation. Mirror neurons, too, probably play a huge role. Most of the time, if someone smiles or laughs, you laugh along.  How many times have you laughed at something you didn’t quite hear because everyone around you laughed?  I do that all the time, and invariably someone turns to me and says “What did they say?” and I have to sit there and feel like a dork because I don’t actually know.

There’s a trend in psychology now, called positive psychology.  One of the important things it brings to the discipline is that it helps get us away from this obsession with abnormal behavior and dysfunction that has taken over psychology.  I talk often of the importance of understanding everyday behavior in class; it becomes depressing to contextualize all behavior in terms of how it goes wrong or is maladaptive, in my opinion.  I think that’s what takes us to the dark side, rather than certain emotions themselves.  People end up getting so caught up in their bad behavior that they downplay or overlook the good behavior, and that’s a shame.  With the rise of positive psychology comes an increased emphasis on understanding happiness and laughter, in figuring out how our nervous system mediates those emotions.  The potentially life-saving advantages of social bonding, which is in part mediated by happiness and laughter, are no less important than the direct benefits of fear and anger.  Social behavior evolved because it conferred an advantage to the individuals who engaged in it; anything that helps us get along in a social group, including mirroring the positive behavior and affect of others, is probably a good and beneficial thing in a broad context.  This is, after all, a major factor in how children learn what to do and how to be.

One goal I have for myself this summer is to revise my emotion lecture.  I think it’s pretty good, but I want to add a section on happiness and positive affect.  Understanding laughter in the nervous system is not only cutting edge in psychology, it has direct benefits for individuals and for my beloved discipline.  And I’m all for that.

Roller coasters

Roller coasters fill me with dread, until they actually start moving. Source:

I kind of like roller coasters.  I don’t love roller coasters in the way that some people do, and there are certain roller coasters I simply won’t go on, such as wooden roller coasters, mostly because they don’t strap you into those types of coasters with hydraulics.  I want that big harness to lock down kind of painfully over my shoulders, and I even pull them down tighter onto my shoulders than is necessary.  And, every single time, I feel a moment of intense panic, because I have been asking myself, all the way through the line, and even as the workers are giving each other the thumbs up signal that will send us on our way, “What if my harness isn’t really locked?”  Of course, it always is, and the car takes off.  But I like them well enough that I can often work up the nerve to ride on them, even if they make me nervous.  That’s part of the fun, right?

Here is here the odd behavior comes in.  The minute the car leaves the starting area, I start laughing.  And I don’t stop until we get to the end.  And it isn’t just a little chuckle.  Oh no, it’s a loud, braying laugh that shakes my whole body and makes the muscles of my stomach ache.  It’s been so obnoxious that sometimes, as we’re climbing that first big steep hill that starts all these coasters off, people have actually twisted around in their seat to give me dirty looks.

What on earth is going on ?  Why am I behaving this way?

Well, in the 70s, Solomon proposed an explanation for this behavior, which he dubbed the Opponent-Process Theory.  There are several different version of the Opponent-Process Theory, each of which addresses different things, such as color vision (which we are familiar with from the lecture on vision) to motivation. Solomon’s theory dealt specifically with emotional responses, and is outlined briefly in the video below, plus I’ll describe it as well.


 So, what Solomon proposed is that every emotional response is biphasic.  In other words, there’s an initial emotional response, which they call the a process, that is experienced.  This a process is followed by the opposite response, the b process.  As the video shows, a person making their first skydive will feel increasing nervousness as the moment of the jump approaches.  Successful completion of the jump produces a state akin to euphoria, which is the opposite of the initial extreme trepidation.

This is a slide from one of my Learning lectures that shows how the two emotions work (on the left) and what is experienced emotionally (on the right).

This is pretty much exactly what happens to me when I ride roller coasters.  I’m horribly nervous standing in line and actually getting into the harness, almost to the point where I feel like I’m going to faint.  As soon as the car gets going, however, the opposite response kicks in.  For most people, it would be after the ride is over.  For me, the worst part is over as soon as the car takes off and I feel safe knowing I’m not going to get flung from the car due to a faulty harness.  So I start laughing.

Obviously, my nervous system is controlling this behavior, and I have to wonder about the exact sequencing of the emotional responses that are experienced.  I think it’s safe to assume my “fight or flight” response, controlled by the sympathetic nervous system, is activated while I’m standing in line.  I feel all the classic symptoms of extreme nervousness.  Nothing new or interesting there—these rides are supposed to make us feel that way (because the designers knew full well about the b process, I think).  The curiosity here is the opposite response.  Why don’t I just go back to my more neutral emotional state after the ride starts?  Why do I have such an extreme response in the opposite direction?

One thing that’s true about our body is that it generally likes to maintain a regulated state.  You’ve heard the word “homeostasis,” which means “steady state” before.  Our body likes to maintain a balanced state of affairs physiologically, neither too hot nor too cold, neither too full nor too hungry, etc.  The same is true of our behaviors as well, including our emotions.  The whole point of the biphasic emotional response is to get back to equilibrium, and perhaps the only way to manage that is for the body to overshoot in the opposite direction after a particularly strong emotion is felt.  So, we feel extreme fear, and to counter that, we feel extreme happiness.  That’s kind of the good way for things to go because we’re left feeling generally more positive even when we get back down to the relatively neutral state.  The bad part is when the initial feeling is extreme happiness, because that’s countered by extreme sadness for a little bit before we recover.  But all of that is necessary to get us back to that even-keel we like to maintain.

I like to think, when I ride roller coasters, that I am laughing in the face of adversity.  However, the truth is, I’m really just laughing in relief!

Several years ago, a study by Ross, Owren, and Zimmerman (2009) made quite a splash.  Prominent scientists, including Jerry Coyne (who pens the excellent blog “Why Evolution is True”) wrote about it, and the study was even featured on news programs that appeared on the BBC.

The reason this particular study generated such interest is because it had long been hypothesized that laughter, some form of which is seen in most of the great ape species, was the result of evolution.  Many researchers, including Provine (1999) argued that laughter was likely present, probably in the form of some kind of panting behavior, in an ancestor common to all extant humans and great ape species.  It’s an idea that makes a great deal of sense.  We have known for a long time that chimpanzees will make a panting sound when tickled that sounds curiously like laughter.  Darwin even describes this behavior in his book on emotional expression (Darwin, 1872).  Orang utans and gorillas do the same.

So here is what Ross and her colleagues did to show that the behavior of laughter is similar across species of great apes, and it is quite stunning in its simplicity.

They tickled a lot of animals.

I mean, imagine yourself as a research assistant in this lab, and your boss comes and tells you that your job is going to be to tickle a bunch of infant great apes!  That sounds like the best job in the world to me.  Specifically, their job was to tickle 21 infant and juvenile chimps, bonobos, gorillas, and orang utans, and three infant humans.  And while they were tickling them, they recorded the sounds they made and subjected them to an analysis.

So, what did they find?

From Ross, et al (2009). This is the tree they constructed by comparing the laughs of several primate species.

As expected, they found some similarities in the acoustical structure of the laughter produced by the species under investigation. Using those similarities, they placed the species into a tree arrangement, which looks like this:

To construct this image, they analyzed the auditory profiles of the laughter from their test subjects.  Essentially, they found the greatest similarity in the auditory structure of laughter between bonobos and chimpanzees.  This is hardly surprising, since those two species are very, very closely related.  Their laughter was structurally similar to humans.  The other two great ape species, gorillas and orang utans, had laughter that was the least similar to human laughter (though it was still fairly close).

What is extraordinary about this particular chart is that it bears a striking resemblance to this:

This is the taxonomic tree for great apes.  In other words, Ross’s, et al (2009) laughter map matches the tree that is produced by analyzing the DNA of all these species, a genetic family tree, if you will, of the hominids.  It is important to note that none of the non-human species have a vocal apparatus that is capable of producing human-like speech, though there are structural similarities in the throat and larynx.

So, why did laughter (tickle-induced laughter, at any rate) evolve?  Provine (1999) suggests that laughter is all about social bonding.  The young of most mammalian species engage in rough and tumble play, and tickling is often an important part of this play.  The tickling produces mutual laughter, accompanied by the release of neurotransmitters that induce positive affect, and the resulting enhanced social bonding is obvious.  This behavior carries over into adulthood and permeates many social encounters. Informal research from Provine’s (1999) laboratory indicate that people laugh the most often in social encounters, many of which do not necessarily include any humor.

I have said in class that the main function of the mammalian brain is to help us navigate the environment.  Some argue that the main function of the human brain is to solve social problems.  I think they are one and the same–the main things we need to navigate in our increasingly complex environment are social relationships of one kind or another.  Our livelihoods, by and large, revolve around successfully navigating relationships with our families, our friends, our teachers, our bosses, our neighbors, and even strangers we encounter in our everyday lives (I consider driving a highly social behavior, for example, even though it doesn’t appear to be that at first).

The other thing that the Ross, et al (2009) study makes quite clear is that laughter in great apes is a distinct and clear behavior that likely serves some purpose (probably social bonding).  In other words, we are not anthropomorphizing the behavior when we hear it.  It really does seem to be laughter in the way we, as humans, understand it.  Though we can never know exactly what a non-human animals is experiencing, we can correlate the behavior that occurs with the laughter.

I want to close out this blog entry with a personal story.  I did quite a lot of research with my mentor at the Smithsonian’s National Zoological Park, in Washington, D.C.  They have several orang utans there, and my mentor was engaged in a research project with them.  The experiments we were doing, which were to look at the cognitive capabilities of the orangs, used touch screens so the orangs could make their responses.  When we were first starting out the project, we had to do a lot of troubleshooting.  This usually involved wheeling the apparatus up, putting a very obvious picture up, such as a big, red leaf, and trying to figure out ways to get the orangs to reach out through the mesh of their habitat to touch the apparatus.  This wasn’t such a problem with the females, since they have smaller hands and could just reach out.  There were other problems with the females, since the first time we rolled the apparatus up to one, named Bonnie, she reached out and punched the apparatus so hard she broke it.

This isn’t Junior, but I wanted to show you what their big, banana-fingers look like. The original picture appears at

The real problem turned out to be the male, Junior.  Male orang utans have very large hands, and these enormous, banana shaped fingers.  We though if we put the apparatus up close enough, Junior could poke his fingers out and make his responses.  So we started training that.  My advisor would often stand near the apparatus, and occasionally would reach in and try to guide his fingers to the stimulus to touch it.  After a few trials of this, he started moving her fingers around whenever she reached in, rather than letting her move his fingers.  We knew he was perfectly capable of touching the screen on his own, so we couldn’t figure out what he was doing until we let him just move her hand around, and he used her hand to touch the stimulus.

At this point, he sat back on his haunches, and started that odd panting laughter that they do.  It was clear to us that he thought this was hilarious.  Of course, once we realized what he was doing, and the fact that he was laughing over it, it made us laugh, too.  Aside from being a great story, his behavior also raises a tantalizing question about a sense of humor in species other than humans.  We know we have it, though humor is highly subjective, and highly complex in terms of behavior.  It’s incredibly difficult to understand what humor is to another species, though I think we got a very clear glimpse of it in the male orang we worked with.

There was a lot of laughter on that research project–orangs are really a joy to work with.


Darwin, C. (1872). The expression of emotion in man and animals. London: John Murray.

Provine, R. (1999). A Big Mystery: Why Do We Laugh? Retrieved 10/9/2012

Ross, M.D., Owren, M.J., and Zimmermann, E. (2009). Reconstructing the evolution of laughter in great apes and humans.  Current Biology, 19, 1106-1111 doi: 10.1016/j.cub.2009.05.028

“Everybody laughs the same in every language because laughter is a universal connection. ”
Yakov Smirnoff

I went two years without cable, relying on Netflix and Hulu+ for most of what I wanted to watch.  With a presidential election looming, however, I simply couldn’t resist the siren song of endless punditry paraded out in front of me on every cable and broadcast channel for the next couple of weeks.  I knew if I got cable for that purpose, I’d also once again lose hours in front of the television laughing as people pawn their family heirlooms and useless junk, try to survive on a remote tropical island, and speculate about ancient astronauts, UFO conspiracies, and the end of the world.  I think I love watching that stuff almost as much as I love watching straight up documentaries about the origins of the universe or animal behavior, even when (and maybe especially because) it makes me lament the lack of critical thinking skills from some of the people on these shows.

So I gave in and got cable again.

And, true to form, if I am home the television is on.  So, unsurprisingly, I was doing some work one morning last week with the TV on when my attention was caught by the sound of laughter.  I looked up in time to see this commercial:

This may be just a commercial, but it is delightful  I found myself laughing along with it as I watched.  I laughed again when I tracked the video down on YouTube.   Laughter, as we see from this ad, knows virtually no boundaries.  Not age.  Not race.  Not gender.  We are all capable of laughter, from the beginning of our life until the end.  This means it is an integral part of our nervous system, as well as an important behavior.

When do we begin laughing, and how does our laughter change as we grow older?  I’d originally thought to write about development of laughter, but I got sidetracked by the fact that the answer to these questions, and indeed the questions themselves are anything but simple since laughter is such a complicated subject.  For example, Meyer, Baumanne, Wildgruber, and Alter (2007) mention an intriguing point about laughter and why it is of interest to researchers.  They report on a widely held opinion that laughter may be a link between animal vocalizations and human speech, with the focus on the affective component of vocalizations across species.  Because laughter takes advantage of our vocal apparatus, and is presumed to have a social and communicative function, understanding laughter is tied to understanding how it is similar and how it is different from speech.  This was one of the surprises as I was looking into this, and in retrospect I guess it shouldn’t have been.  But I always simply considered that we speak, and that we laugh, and never stopped to realize that we often do both together.  Or that the same structures we use to speak are also used to laugh.  It wasn’t until I was writing up my last blog entry, and reviewing Darwin’s book on emotions that it occurred to me that they are probably very related in the brain.

Interestingly, according to Meyer, et al (2007), there is no “laughing center” in the brain.  While the same might be said of language, there are clear areas associated with language in the brain, most notably Broca’s area and Wernicke’s area.

The insular cortex.  Click the picture to read an interesting blog entry about the insular cortex.

They say that laughter seems to be more distributed in the brain.  Major emotion centers of the brain, particularly structures found in the limbic system (such as the amygdala, the thalamus, and the hypothalamus) become active when we laugh, along with many structures from the frontal lobes to the brainstem that mediate motor behavior (for the physical behavior of laughing).  When participants were exposed to laughter, backwards laughter, and silence, the amygdala only became active to the sound of regular laughter.  They suggest that the amygdala, the insula, and areas of the superior temporal lobe particularly mediate the perception and affective responses to laughter (Meyer, et al).  Incidentally, this blog has made me very curious about the insular cortex, since it seems to play a special role in socially mediated emotions, such as embarrassment, among other things.

So I think it’s kind of fitting that an advertisement became the inspiration for this blog entry.  An ad is nothing if not an attempt to communicate, to evoke some kind of emotion from the person viewing it.  In this case, the makers of the ad want to sell you a car, but they chose to go about it without ever once showing you a picture of said car or using much in the way of language (and in fact, no spoken language at all).  Instead, they use a fundamental human behavior, one that taps quickly into the emotion centers of our brain, such as the amygdala and the insula, to evoke an emotional state in us that they undoubtedly hope you will associate with their product.

Most importantly, however, I like to think that the makers of this particular ad also wanted to remind us how integral laughter is to the human condition.


Meyer, M., Baumanne, S., Wildgruber, D., & Alter, K. (2007). How the brain laughs: Comparative evidence from behavioral, electrophysiological and neuroimaging studies in human and monkey. Behavioral Brain Research, 182, 245-260.