When was the last time you had good ol' belly laugh?

I know the last time I did was during the recording of the last Psychobabble, when Jess made a comment about watching Psycho then visiting your hypothetical mother-in-law who 'has always regarded you as a temporary fixture in her child's life'. For whatever reason this cracked me up. I ended up keeping a few seconds of my laugh in the recording (something I usually don't do), but edited out >60% of it. I made the decision to keep it because it sounded good. It was an honest-to-goodness belly laugh, and such a genuine display of emotion, I reasoned, could only be a good thing.

Then I got thinking. Why do we laugh - what purpose does it really serve?

But first - you need to laugh. Most of you have probably already seen it, but I guarantee you'll laugh again.

Who was laughing along? That baby cracks me up. I love it that he laughs so much he bangs his head (repeatedly) against the furniture. The father laughing along helps the situation. You can't help but know that everyone involved is just having an honest and genuinely happy time. But ... are they having fun, is it funny, is it an expression of joy, is it slapstick; and how is it different from the laughs we can have at a piece of wit, or an implicit in-joke, or the relief from some kind of near-miss?

I can't really be sure, and I'm not sure we can know all the subtleties, but it is clear that laughing is a social phenomenon.

First off I feel a little validated that I kept my laugh in the podcast (short though it was). Reysen (2006) ran a really simple little experiment that was modeled off a lot of the smiling literature. He obtained a bunch of laughing stimulus by videoing some willing participants (men and women; who were acting students) who read a passage while viewing funny pictures [perhaps like this one]...

He then asked the same group to read a passage and fake their laughter as similarly as possible as they could to their original laugh; and to read the passage without laughing (neutral).

Reysen (2006) then showed this stimuli to some undergrads. He found that people were rated as more likeable when they were laughing (genuine AND fake) compared to no laughing (neutral), but that there was no significant difference between likeability ratings between genuine and fake conditions. His data also revealed that people were slightly better than chance at detecting a fake laugh from a genuine laugh (the mean correct responses were 56.5%). There were a few things to note, though. Men often silently laugh, whereas women tend to laugh out loud. As a result he found the women who were laughing were rated as more likeable than men doing the same. In a second study he controlled for this by showing only pictures (not videos) under the same conditions. He basically replicated the findings:

a) Fake and Genuine Laughs were more likeable than neutral expressions;

b) Fake and Genuine Laughs didn't appear to differ from each other;

c) Women were still more likeable;

d) People could detect fake vs. genuine at 54.88% (significantly above chance)

The Women = Likeable is a little confusing, because I can think of no immediate reason why a woman laughing should be more likeable than a man doing the same (the raters were both men and women). Some interesting implications there, I should think.

But there are other reasons why we might laugh.

"In thinking about laughter's functional significance, one should bear in mind that laughter is decidedly a social signal, as it is far more likely to be produced in the presence of another individual than when alone... We conceptualize antiphonal* laughter as being part of an affect-induction process that promotes affiliative, cooperative behaviours between social partners "

Smoski & Bachorowski (2003)

*'Antiphonal' is a fancy biological terms that refers to co-occurring vocalizations in animals. It's used predominantly in the animal behaviour literature. The term 'Reciprocal' works just as well in the human context.

So here's what Smoski & Bachorowski (2003) did. Imagine yourself entering the lab with a friend (same sex, or different sex; depending on the condition) and being asked to come up with as many names for an inflatable copy of 'The Scream' by Munch.

... now imagine that you and your friend have to draw crayon portraits of each other.

... hilarious, right? Now imagine you had to do all that with a stranger (same or opposite sex).

...really, really awkward...

Here's what they found:

[Smoski & Bachorowski, 2003]

Not too surprising, really. Friends laugh more often than strangers. The real stand out (for me) is how much more Female strangers laugh together, compared to Male strangers, or mixed partners. I won't go into what Smoski & Bachorowski (2003) said, but I'll ask you to hypothesize why you think men and women differ in the propensity to laugh with each other.

Now Smoski & Bachorowski (2003) coded anything that seemed like it would be a laugh in an every day context. So a certain kind of grunt or snigger, or a catch in the throat that seemed like laughter was coded as laughter. This seems fair to me, all said and done, we're all pretty experienced at determining a laugh when we see one.

Yet not all laughs have been created equal, according to Bachorowski and Owren (2001). Given the data and the name there I'm surprised that they didn't control for type-of-laugh in the last study; alternatively there's some piece of the literature that diminishes the following finding. However, it seems relevant with my limited understanding.

The following are results obtained by getting male and female listeners to rate how much they would like to meet the laugher, how friendly they sound, and how sexy they sound.

[The two bars on the left are 'voiced' and the two bars on the right are 'unvoiced'. That is left is out loud laugh-as-a-sing-song noise, and 'unvoiced' as a grunt, snigger, chuckle, etc.]

They found voice laughs generally elected more positive emotion, and female voiced laughs were more friendly and sexier than male voiced laughs. On the flip side, an unvoiced female laugh was usually considered less positive than a male voiced or unvoiced laugh, or a female voiced laugh.

[Note: The 'Laugh Track' question is how likely one would be to endorse the laugh for a laugh track].

So I think the moral of the story is to laugh if you want people to like you. Kind of lends a bit of a support to the joke about always laughing at your bosses jokes, but turns it on its head. We don't laugh to protect out Boss, we laugh 'cause we want our Boss to like us. There is a figure in my life who tells the most banal jokes, but who always cracks the room up. I always intuited that we did it because we were being polite, but it seems the motivation may be a little bit more self-serving. Sure, there's a lot of other things going on in that context but it seems like a plausible extension of a more personal relationship.

Finally, here's a quick video that raises some interesting questions. Why is she laughing? What's going on? Are other people laughing (in her head) too? What kind of laugh is that? A laugh at wit? A laugh between friends? A laugh at another?

Reysen, S. (2006). A New Predictor of Likeability: Laughter North American Journal of Psychology

Smoski, M., & Bachorowski, J. (2003). Antiphonal laughter between friends and strangers Cognition & Emotion, 17 (2), 327-340 DOI: 10.1080/02699930302296

Bachorowski, J., & Owren, M. (2001). Not All Laughs are Alike: Voiced but Not Unvoiced Laughter Readily Elicits Positive Affect Psychological Science, 12 (3), 252-257 DOI: 10.1111/1467-9280.00346