Facial expressions were a great source of interested to Charles Darwin. What you see here is a series of illustrations of experiments done at this time, where volunteers had their faces shot so as to contort them into different expressions sort of to provide a science of the face. Darwin's view was that facial expressions were interesting in so far as they talked about the origin of the expressions in our evolutionary history, and the origin of the emotions that gave rise to the expressions. Why is it that anger gives us rise to one face and sadness another? How can we develop a theory of this and relate it to the facial expressions of our neighbors like chimpanzees or even dogs. All of this presupposes a universality. To make the case for universality, I'll let Paul Ekman start it off. Why I have a face. My God, how can we live without a face? We wouldn't know who we were, one from another. We wouldn't to be able to know people's age as readily. You would lose age, you'd lose identity. It's a site for sexual signals, for our feelings, our emotions. We wouldn't survive without faces. For most people, their face is really their sense of identity, it's who you are, what marks you as, how you tell one person from another. It's probably the most personal or one of our personal parts of representations that we have. Not just because of the sensors. Although, clearly if your taste and smell and eat, and breath, that's awfully an important part of yourself, but yeah, behind the face is the brain and the face of course is the display system, the primary one for emotions. In my first wave of study, the first series, I just worked with people in literate cultures. South America, Japan, Europe, and North America as well. But the problem was you could always say everybody had learned his expressions from the tube or the magazine. Maybe it was John Wayne and Charlie Chaplin, not our evolution that was responsible. So to answer that, I went to 1967, 20 years ago, to a pre-literate culture in New Delhi, a group that had not had any contact at that time with the media. The first thing we did was to show the picture and ask them to make up a story. What happened? Why is this person showing this face? We analyzed those, and that's how we got for example that the best most common story for a fear face was a wild pig is after you and you have no weapon. Best story for a sad face, when it come up most often was when a child had died. Let's make a face. Here are the instructions, you can do this at home. Lower your brows and draw them together, tense your lower and upper eyelids, stare, your eyes could bulge a bit, and now press your lips together with the corners straight or down. You'd probably look like this. This is a face, the emotion that this face corresponds to is anger. If you saw somebody with this face anywhere in the world, it's a reasonable bet that they're angry. It's not perfect, there are subtle differences in facial expressions, there are differences in how people show it. Of course he may just be pretending to be angry or trying to fool you and yet, there are irregularities in universals. There are databases of facial expressions from all over the world. This one's from Japanese women. Look at facial expressions, and they look kind of the same. Let's do another face. Raise the corners of your lips back and up, raise your cheeks and raise your lower eyelids if you can. Don't injure yourself. You're probably smiling. This is a series of pictures taken from the internet of course of smiling babies, because babies smile early on. This is my younger son Zachary when he was smiling as a baby. This is just to show that the facial expressions of non-human primates, though far from identical to that of humans, share some commonalities with our own. Like other facial expressions, smiles serve as social signals. So. It's not quite right to say we smile when we're happy. We're more prone to smile when we're happy and we want others to know it. So for instance, there's been studies of athletes going on stage or doing their athletic performance. Bowlers, when they knock down all the pins, are often have stoic faces, and then they turn around to face people and then they grin. Olympic gold medal winners are not typically smiling all through the ceremony, but when they stand up to get their metal, they beam. If you think about the times when you're very happy but by yourself, you might notice you're not necessarily smiling. Smiles are social. Now, one of the cool findings of the study of smiles is that there's different types of smiles. Here's Paul Ekman smiling twice. But these are not the same smiles. Ask yourself for a second, which smile do you see is more genuine. Well, one of them is what's called a happiness smile, sometimes known as a Duchenne smile, and it's a real smile. It involves movements around the eyes, that's the biggest difference. The other one is what's used to be called a Pan Am smile or greeting smile, and it's a fake smile. It's just done below the nose. You turn your mouth outwards but that's kind of it. It turns out that even babies can distinguish between the two sorts of smiles. It turns out that studies of happy versus unhappy couples find that the happy ones have more duchenne, more sincere smiles. The college yearbook photos, you could look at people and learn a lot about them from seeing what kind of smile they produce. A third sort of smile is what's known as a the coy smile. It's very interesting. It is often known as an appeasement smile. Somebody who has a coy smile will sometimes look away, that it's related to being embarrassed, and it's related to a desire to affiliate. If you're feeling awkward and you're a bit nervous and you want to say "Don't hurt me", you might do kind of a coy smile. Here is a clip which I'll work through of a baby, coy baby smile. The baby is doing this and doing that. It's kind of adorable, and maybe that's what it's for. Maybe what the coy smile is for is to say "I'm adorable. Please don't kill me."