字幕表 動画を再生する 英語字幕をプリント CARL SAFINA: All right, well, we're going to talk about basically the subtitle of this book. This book came out two days ago, so it's brand new. And we're going to start in a kind of familiar place. Many of us have animals at home, and we've often asked ourselves these questions, right? How many people have asked themselves if their cat or dog really loves them, or just wants food, or whatever, right? That's pretty common. And we think, well, it's impossible to know. But is it really? Is it really impossible to know what's going on in the mind and the heart of our pets? Well, in a way, no and in a way, yes. What's really going on in those minds is the question. Another question is-- it's not showing up very well there-- how are they like us? But I don't like that question so much. It's an inescapable question because they are in many ways like us. But when we say, how are they like us, we put the attention back on us. And us is our favorite story. We like to talk about ourselves. And what we're really supposed to be doing here is asking, how are they like us or not? Who are we here on Earth with is really the point. And what is going on in these minds that are our co-voyagers on planet Earth? Is there any way to get into the mind of an elephant, for instance, or any other kind of creature? Well, I think there are actually several really good ways of seeing in. You can look at their brain and their mind. You can look at their body, at the logic of their behavior, at their evolution. So the first thing is if we're interested in minds is to know where is the mind? In many parts of human history, people have thought the mind is in the heart or the mind is in the soul. The mind is a disembodied spirit that is our eternal presence in the universe, all these different kinds of things. So first of all, where is the mind? And a hint is that if you have a heart surgery, it's not going to damage your mind. But if you have brain surgery and something goes wrong, it's going to damage your mind. Your mind comes from your brain. The mind is in the brain. And we might say, oh, we have no idea if animals are experiencing anything. But we use their experience all the time. For instance, if we want to know if cosmetics are going to sting us, we test them on the eyes of rabbits to see if they sting the rabbit. So if they sting the rabbits, the rabbits are having exactly the same experience of pain, the sensation of stinging, as people have. When dogs are depressed, or if dogs have obsessive-compulsive disorder, they respond to the same drugs in the same way that we give to people-- antidepressant drugs. Why? Because the part of the brain that gets depressed and the chemicals that create depression or obsessive-compulsive disorders are exactly the same. They're not experiencing an analogous problem. They're having the same problem in the brain of a dog. Or even as low as down below vertebrates on the evolutionary timescale, or before vertebrates, something like a crayfish, you can make crayfish develop anxiety by giving them little electrical shocks and making them feel nervous and tense. And so they retreat into their burrows. They stop exploring. They won't eat. You give them the same anti-anxiety drugs that work on people, the crayfish relaxes, comes out of its burrow, and starts exploring again. So these are ways we can manipulate minds with different kinds of tests and drugs to see if they respond the same way ours do. And that's a good way in. Now you can say, well, we can see brains, but we can't see the mind. And that, in a sense, is a fair enough statement. I mean, it's true, right? But I can't see your mind. You can't see my mind. It's always true. But where is our mind from? Where is the human mind from? The human mind is from the minds of non-humans that were here before us. When evolution created-- in a sense-- humanity, humanity evolved from something. We had to use the parts that were already in stock and make a few tweaks. And the parts that were in stock are the highly developed brains of the other mammals from which we evolved. So if you look at a mouse brain, and you look at a human brain, it's a very similar, very recognizable kind of thing. The human brain looks different. It's got lots of convolutions in the forebrain. That's where a lot of thinking happens in humans-- human thinking. If you compare our brain with a chimpanzee brain, you see basically that we are apes, so it's not too surprising that the human brain is basically a very big chimpanzee brain. So it's not logical to think that the human brain only does things that only humans do and nothing that happens in any other brain. It's just completely illogical. We're all very insecure, we human beings. We can soothe our insecurity with the thought that at least we have the biggest brain, right? Except, uh-oh, there's a dolphin brand. It's not only much bigger. It has way more convolutions than ours. It's doing something with all of those neurons and all of those networked connections. We can see the working of the mind in the logic of behaviors of other animals, the fact that their responses and emotions make sense to us. We don't see-- well, we'll go through a few, OK. We say these albatrosses here, they're dancing in courtship. And why do we say they're dancing in courtship? Because that's a very recognizable thing. It happens at the same time that humans dance in courtship. It's something that we do, pre-bonding and pre-mating-- same with them. We look at elephants like this. Now, elephants don't do this if they're surrounded by all kinds of dangers. And they don't do this if they're famished. They do this if everything is cool and nice, and they're relaxed. And the parents are still a little bit on guard while they let the babies lie down and not worry about anything. That totally makes sense to us, and it's totally appropriate to the situation. So we can tell by the logic of their behavior, something about what's going on in their minds. They are protective and parental, like we are protective and parental, whether they are humans or elephants or mammals in water. The differences between us are mostly the outer contours and a few internal tweaks. So one analysis is only humans have human skeletons. But it's not true that only humans have skeletons. And only humans have human minds, but it's not true that only humans have minds. When help is needed, help is provided. They're not trying to eat their baby. They're trying to help it to its feet. I love this picture. This is the cover of the book, actually. That's a newborn elephant that has never stood up before. And its mother and two cousins are helping it to its feet for the first time. When animals are very young, they're very curious. They don't know what things like egrets are. They check everything out, because they have to learn what's in their environment. And many animals have to learn just about everything. Baby elephants don't even know that lions are dangerous. They have to be taught by their parents and by example that lions are dangerous, that bees can sting you, and these kinds of things.