(Image source, the BBC’s Look Around You.)

Okay class, pens down. Let’s let [someone] back in. We just need to finish the experiment before I can tell you what was going on.

I’ve no idea whether this’ll work or not. Given we’re in a totally uncontrolled situation… well. Okay. [someone] is going to look at you for a bit, and try to assess your emotional state. [someone], if either side of the room looked happier to be here, which would it be? Can you write that down? Leave it over there?

We’ll have a look at the end.

What was I looking for? Putting a pen in your lips, like that, is contorting your face into a smile. It turns out that emotion doesn’t just get manufactured in your head and then represented on your face. If you move your face into a smile, it actually makes you happier.

Same with the other pen. Pushing your top lip up activates the same muscles as scowling. Again, it affects what you actually feel.

Okay, to be honest it doesn’t really matter whether this works or not. It’s a bit silly, there are a lot of people here. In experiments, this does work.

If you got a subject, told them a joke, and got them to rate it out of 10… let’s say they rated that a 7. Or 100 people, on average, rated it a 7. Now you do it do people with the pen in their mouths… it comes out an 8. To the people pulling their face into a scowl, it comes out a 6.

I promise you this is going to be relevant.

Right, so what’s happening? The point it, why should you brain bother storing the emotion in your head and on your face? Instead of duplicating it, just store it once—on the face. Given your face is always there, your brain just treats it as reliable, permanent storage. It’s more efficient for the brain to do that.

This is how emotions are shared, by the way: When you see something, like a gesture, you can’t help but copy it. If you see smiling, you smile a bit yourself, and then actually feel happier.

This is a general truth.

Matt Webb, S&W, posted 2006-04-13 (talk on 2006-02-08)