Here's another emotion. This is a picture of Lee Harvey Oswald, the assassin of John F. Kennedy, himself being shot by Jack Ruby, and zoom in on a police officer standing next to him. You see a typical expression of fear. He just saw a man being shot right in front of him, it's a violent confrontation. Of course, he feels fear. Now, fear is interesting. It's a social emotion because you can be afraid of people, but it's not primarily social. We can be afraid of a lot of other things as well, and when we ask ourselves, what are people afraid of? This is simple enough to find. You can simply ask people or look at their behaviors, but you find that people are afraid of things like spiders, snakes, heights, storms, large animals, darkness, blood, strangers, humiliation, deep water, living home alone, and what do these things have in common? Why aren't we afraid of guns and cars, and electrical outlets? Cars and guns, electrical outlets are very dangerous. For electrical outlets, kids get yelled at for going near. While guns and cars kill people, cars are particularly dangerous, yet I've never met anybody don't expect ever to meet anybody who has a phobia of cars. Why no people who will leave the room, if there is a snake anywhere nearby. So, where does that come from? We can also ask, what are non-human primates afraid of? What our children in Chicago afraid of? What are the biggest fears for instance of Children in Chicago? The answer for that is they are afraid of snakes and spiders. These are kids who have never seen a snake or a spider outside a visit to a zoo or watching them on TV, and the answer is that this is very badly explained by a class with conditioning theory of fear. It's not as if all of us have been attacked by a dangerous spider which causes enormous amount of pain, and now we're afraid of it. We've learned to be afraid of it. Rather evolution seems to play a role, that while certainly we can learn to fear certain things and our fears can be shaped by our experiences, our traumas, it seems that evolution has primed us to fear some things and not others, and I think the study of fear and emotion of fear is a wonderful laboratory through which to explore how evolution has shaped our minds. Before I leave facial expressions, fear was the last one, I want make one final point in this lecture, which is that they're awfully hard to fake. So, the clip I'm going to show you now, I'm going to end this lecture with, is of a girl who was surprised by her father. There are many of these videos on YouTube. They're very moving to see, and look at her reaction and ask yourself, could she be faking? Ask yourself if you're in her shoes, and somebody offers you a lot of money to fake that, that man's not your father. You just post to pretend. Could you do it? I think the answer is no, except for very trained, very skilled actors. Genuine emotions involve changes that a face in the body involve an intensity that is hard to fake, and say something we waited for, which is if emotions are signals, they evolved to be trustworthy signals. They've evolved to be signals of a sort that other people could take account of, and why is it signals would evolve? Is actually a very interesting question. But here I'm going to show you the clip. Oh! Oh, My God! Come here baby.