JAD ABUMRAD: Hey, I'm Jad Abumrad.

ROBERT KRULWICH: And I'm Robert Krulwich.

JAD: This is Radiolab. Today's hour ...

ROBERT: Animal minds. Animal minds.

JAD: Right.

ROBERT: Do—can—can one animal really know what's going on in another animal's head?

JAD: Yeah, like really know?

ROBERT: Really know.

JAD: Thanks for meeting us.

JAD: So we were thinking about that whale story that we heard before the break.

ROBERT: Yep.

JAD: You know, where the divers meet the whale, and they were sure the whale was saying thanks.

JAMES MOSKITO: Literally saying thanks. Thanks for helping me out.

JAD: Okay that is their opinion, but we wanted to know, like, what can you actually scientifically say about that kind of exchange? And that question led us ...

PRODUCER: Introduce yourself.

JAD: ... to this guy.

PATRICK HOFF: My name is Patrick Hoff. I am a neuroscientist at Mount Sinai School of Medicine in New York.

ROBERT: Although, actually the truth is he's really from some place like Geneva. He's a Swiss from the French part of Switzerland.

JAD: Right. Bang on! We came to him because he may have found a way of separating the animals, of knowing which animals can genuinely have human emotions, and which can't.

PATRICK HOFF: It starts—it starts in 1995. We were studying the anatomy of the human cingulate cortex.

JAD: That's part of the brain that's right here. Kind of between your eyes, but down.

PATRICK HOFF: And a student in my lab, Esther Nimchinsky ...

JAD: She was looking at some brains, and she saw ...

ROBERT: Something odd.

PATRICK HOFF: These very slender bipolar neurons. I've never seen a neuron like that. Maybe it's abnormal, it's probably pathological.

JAD: Just to be sure, she got some slides of other human brains, looked in the same place.

PATRICK HOFF: And we ...

JAD: There it was again.

PATRICK HOFF: ... started to see them in ...

ROBERT: And again.

PATRICK HOFF: And we were very pleased. So okay, we have discovered a new cell type. Whoo! Something that is unique to humans.

JAD: But then they went to the library and discovered that some guy ...

PATRICK HOFF: Who's name is Constantin von Economo.

ROBERT: Costanto ...

PATRICK HOFF: Constantin von Economo.

JAD: This Romanian guy.

ROBERT: ... von Economo.

JAD: He'd seen these cells 70 years ago.

PATRICK HOFF: And he named them spindle cells.

JAD: Because of their shape.

JAD: Oh, that must have been a very sad day for Esther.

PATRICK HOFF: No. No, no.

JAD: Because now they believe that these little brain cells may be a key to how humans relate to one another, and whether or not other creatures can relate to us in the same way.

ROBERT: Right.

JAD: Is it possible to—for us to see a spindle cell?

PATRICK HOFF: Yeah, we can—we can show you spindle cells.

ROBERT: Patrick Hoff took us down the hall.

JAD: Yep.

ROBERT: Jad went first and parked in front of a big microscope.

PATRICK HOFF: Here, you can look at it.

JAD: Will it be obvious to me?

PATRICK HOFF: Yeah.

JAD: From looking at it?

PATRICK HOFF: Crossing the middle of the field, you can see a series of tall slender ...

JAD: It's making me dizzy a little bit.

PATRICK HOFF: We have one, two, three, four, five.

JAD: Is that the spindles?

PATRICK HOFF: Yeah.

JAD: Oh, they're everywhere!

PATRICK HOFF: Yeah.

JAD: Oh. You want to see them?

ROBERT: What do you mean do I want to see them? I mean, yeah! Here you hold the mic. Oh, yeah! There's a whole troop of them, and they're long and skinny and purple.

JAD: It's funny because the normal brain cells which you can also see in there are like dot, dot, dot, but these ones are doooo! Like little purple bananas.

ROBERT: Like a team of purple bananas.

JAD: And the thing that makes these cells so interesting ...

ROBERT: All seeming to head off in this direction.

PATRICK HOFF: Yeah.

JAD: ... according to Patrick Hoff is that, you know, in the normal brain cells, they just talk to their neighbors. But these because they're so long ...

ROBERT: They seem to be yelling across a big distance.

PATRICK HOFF: Exactly. We know that these cells send an action at some distance.

JAD: It's across the valley.

PATRICK HOFF: Yeah, it's across the valley, exactly. It's projecting.

JAD: But projecting what? And from where to where? Well, Patrick Hoff doesn't entirely know, but he says he can make a pretty good guess based on—well, if you look at the microscope you do notice some things.
PATRICK HOFF: Yeah, yeah. So here, here, on the top of the spindle points toward the surface of the brain always.

JAD: The top, he says, seems to shoot up, towards those more modern parts of the brain that involve ...

PATRICK HOFF: High-order cognition.

JAD: Yeah—language, abstract thinking. Whereas the bottom of the spindle seems to shoot ...

PATRICK HOFF: Down.

JAD: ... deep down.

PATRICK HOFF: The lower centers in the brain.

JAD: Towards those older parts of our brain that involve feelings, emotions, instinct. So perhaps—this is what Patrick Hoff thinks—that these cells are a kind of network, a really important one that allows the different parts of our inner selves to connect. Like, you've got the parts of us down here that feel things can now communicate with the parts of us up here that think things. And this is an oversimplification of course, but the point, the larger point is that this is exactly what happens when you look into the eyes of another human being. Because it begins with a kind of thought. Your eyes seem sad, but then that thought within you travels a great distance and connects with the feeling of sadness, so that you feel sad too.

PATRICK HOFF: Yeah.

JAD: I mean it's the basis of kind of empathy.

PATRICK HOFF: Exactly, exactly. You know I see you're happy, you know, so that I feel good about it.

JAD: You know and consider those times—I mean not just empathy where, like, your thoughts and feelings are in conflict, and they've gotta really talk to one another.

ROBERT: Like for example, when you get in front of me at the microphone yet again.

JAD: [laughs]

ROBERT: And I hate you, but I know that I have to work with you, so I—I sit on that feeling. I just sit on my—it's going down to the bottom of my brain, but I say take a nap.

JAD: See, that's the best part of your spindle situation is that it's not just that thoughts connect to feelings, but those thoughts can sometimes suppress feelings.

JONAH LEHRER: Yeah, I—you know, I think that's the idea is that humans in social interactions can't rely on these hard-wired emotions in the same way other animals might be able to.

JAD: That's Jonah Lehrer, science writer. A regular Radiolab contributor, and a guy we often call to help us make sense of things.

JONAH LEHRER: You know, we can't like a dog just hump every other dog and see what happens.

ROBERT: [laughs]

JONAH LEHRER: We've—we've gotta flirt and be funny and, you know, buy a couple of drinks.

ROBERT: [laughs]

JAD: [laughs]

JONAH LEHRER: But—but that was—you guys have to cut that because I don't want hate mail from ...

ROBERT: I am so astonished!

JAD: [laughs]

JONAH LEHRER: Well, I was like, "Wow!"

ROBERT: We've gotta use that, Jad.

JONAH LEHRER: I just—I just turned into a frat boy. So—but the point being that our social interactions are very complicated, in that we can't rely—it's much tougher for humans to rely on simply these hard-wired, primitive instincts. You know, so the job of spindle cells is to simply broadcast content to the rest of the brain.

JAD: Because without our whole brain involved, we'd never be able to navigate the social world and make any kind of connection.
ROBERT: Right. So if spindle cells then allow us to talk gently and emotionally to one another, the question is—this is the question for the hour—what about intra-species? Is it intra- or inter-?

JAD: Intra.

ROBERT: To look within.

JAD: Like, an intranet.

ROBERT: Yeah, that's inside.

JAD: I think across species is what you mean.

ROBERT: Does any other animal have spindle cells?

JAD: And as it happens ...

PATRICK HOFF: So where I'm taking you to my cold room.

JAD: ... just down the hall from his office, Professor Hoff has a freezer.

PATRICK HOFF: Where I store the specimens.

JAD: This is a very, very big door, too.

PATRICK HOFF: So ...

JAD: Full of brains.

PATRICK HOFF: Yes, so it's going to get really cooler here.

JAD: All different kinds.

PATRICK HOFF: We have brains of all your species, the cetaceans are over there. We have the great apes around here.

ROBERT: This is the whale wall.

PATRICK HOFF: That's the whale wall, yeah.

JAD: He's got dozens and dozens of brains in buckets and in jars. And he keeps them all organized where each category of species has its own shelf.

PATRICK HOFF: You have more apes down there with gorillas and orangutans.

ROBERT: Aah!

JAD: Whew!

ROBERT: It was really cold in there.

JAD: So what they did was they took a bunch of those brains off the shelf and walked them down the hall to the lab, and put little pieces of them under a microscope. They didn't expect to find any of those bizarro neurons in any of these other creatures because he was pretty sure ...

PATRICK HOFF: This is something that is unique to humans.

JAD: But ...

PATRICK HOFF: One day we were looking at the brain of the humpback whale, and we stumble on spindle cells, plenty of spindle cells.

ROBERT: Oh, so what was that? Did you—were you surprised?

PATRICK HOFF: And I was there, and said "Okay, this is fascinating."

ROBERT: You weren't expecting that?

PATRICK HOFF: I was not at all expecting that.

JAD: But on the other hand ...

PATRICK HOFF: Here we have the—the humpback whale which is a very social animal. They—they form clans, they communicate. The males have a song. They hunt together, they develop hunting strategies, which requires perfect coordination of many whales. So they have to act together to do that.
JAD: Now if acting together is the key, you know, in having complex social structures, well then these things shouldn't just be limited to whales. And in fact, over the years Hoff and other scientists have found spindle cells in chimpanzees, elephants, dolphins, gorillas. Which begs the question, like, if we want to have an experience with another creature, and not just at the zoo, but a real shared experience, do those creatures need to have these things?

JAD: Do you think the existence of spindle cells creates more of a possibility of having that cross-species sharing moment?

PATRICK HOFF: I think so. If we assume that these cells have such an influence on the sociability of the species, it is very likely that you would experience something of that kind with a species that has them. I doubt you would get a very good experience if you were trying to do this with a hyena.

JONAH LEHRER: So maybe what we see when we look into, you know, these sad eyes of a blue whale, or when we look into, you know, the eyes of an elephant cradling a baby elephant, which are just the cutest things on earth, maybe what we recognize is—is that same flavor of emotion, that same inner life of feeling. Maybe—and this is a big maybe—maybe that inner life requires spindle cells.

ROBERT: But how big is that maybe? I mean, it sounds like a really maybe maybe.

JONAH LEHRER: I mean, you know, at some point this is all just a—I think this is still very theoretical.

ROBERT: And in fact if you ask people, like Clive Wynn the fellow who—who pooh-poohed our whale thank you from before?

JAD: Mm-hmm.

ROBERT: Ask Clive, like, could you look at an animal and find something in the animal that says yep if he has that, he's got feeling?

CLIVE WYNN: Well, wrong. I don't for a moment imagine that there's gonna be a type of nerve cell or a type of structure in the brain which is gonna be such an acid test of whether an animal has a particular psychological capacity that we can then find that kind of neuron and say, "Well, now we know," without having to look at the behavior of the animal, now we know that this species has this or that psychological ability.

JAD: Well let me ask the question a different way. I mean, do you think—spindle cells or no spindle cells, let's just toss them out for a second—do you think there are a category of creatures that are more likely to have empathic experiences with us? Would you draw a line between beings?

CLIVE WYNN: Well the thing I would—the thing I would emphasize if we're looking for empathy between different species, is their developmental experiences.

ROBERT: To make his point, Clive told us about this experiment. He says let's take a chimp with all the spindle cells inside the chimp brain in there. Put the chimp in a room, and in front of the chimp let's put two cups face down. Now one of the cups has a grape or something delicious under it. And the chimp doesn't know where the grape is. It could be under cup A or cup B. So what you the experimenter do is you simply point to the cup that has the grape. Like, that's the one. That one right there.

CLIVE WYNN: And all the animal has to do is to go to the cup that's pointed to. It seems simple enough.

ROBERT: But chimps, Clive says, chimps ...

CLIVE WYNN: Find this stunningly difficult to understand.

ROBERT: Get this wrong.

JAD: What do you mean?

ROBERT: I mean, they just look at you pointing, and they look at you pointing, and they look, and you're pointing, and they just go what?

CLIVE WYNN: Whereas dogs ...

ROBERT: Who don't have spindle cells.

CLIVE WYNN: ... most pet dogs get this from the get go.

JAD: Wait, dogs can do this and chimps can't?

ROBERT: Yeah, yeah, yeah.

CLIVE WYNN: They quite spontaneously recognize that you should go where—where they point.

ROBERT: And Clive says the explanation here is not that dogs have some special cell in their brain. It's simply because ...

CLIVE WYNN: Because they grow up in our households.

ROBERT: They grow up with us.

CLIVE WYNN: Right.

JAD: Huh.

ROBERT: To test this idea he did the same study.

JAD: The pointing one?

ROBERT: Yep. Except this time with some wolves.

CLIVE WYNN: Because wolves are the animals from which dogs are descended, but they haven't lived in human households, obviously.

ROBERT: And normally, like the chimps, wolves totally screw up the pointing test.

CLIVE WYNN: But we've done some tests on some wolves that were hand reared by human beings and are very friendly to human beings, and we find that those wolves behave just like the dogs. That they are just as good at following the human pointing to find the food.

JAD: Really? Did you have to train them, or ...

CLIVE WYNN: No, we did not train them.

JAD: They just picked it up?

CLIVE WYNN: Well, they just picked it up. But these are exceptional wolves insofar as they were reared by human beings. They were bottle fed when they were wee babies.

JAD: Ah.

ROBERT: Ah.

CLIVE WYNN: Because there are things that go on earlier in our development that are crucial, and that include learning who are your—who are your kind. What the—who am I? What am I? And you learn that in a critical period in your early life by looking around you and seeing who you're interacting with. Pretty much every dog you might meet has learned to accept humans as social companions, and that's because it was reared in a human home, and because evolution has prepared it with a relatively slow development so that it's pretty easy to tame a dog. The wolf on the other hand, it goes through its childhood, and adolescence in the blink of an eye, in the course of just a handful of weeks. And so it's actually extremely difficult to successfully hand rear a wolf because you have so little time available to you, and you have to invest 24 hours a day, seven days a week during that brief period that a wolf is open to the possibility of learning who its companions might be.

JAD: That's really interesting. You know, one of the pieces of the interpretation that I find intriguing, and I want to run by you, is that when ...

ROBERT: Ooh, that's so interesting. I'm now sitting here thinking ...

JAD: [laughs]

ROBERT: ... boy, if I could raise a whale with a baby bottle, then I would know whether the whale was saying thank you to me because I would've learned—it's not like I have to learn whale, but whale would've learned human.

CLIVE WYNN: Well, that's right. I mean, of course this is completely hypothetical. The whale is a really bad example to choose.

ROBERT: [laughs]

CLIVE WYNN: But my guess would be if you bottle fed a whale, you would get a whale that might plausibly do something like a behavior that expresses thanks.

JAD: [laughs] That is such a hard mental image to conjure.

CLIVE WYNN: Well, that's right. That's right.

JAD: Robert bottle feeding a whale.

ROBERT: Yeah, well because we have to keep rising to the surface for 21 years to breathe.

JAD: [laughs]

ROBERT: Before I actually get to the experiment.

CLIVE WYNN: Yes, there a number of drawbacks to that experiment.

ROBERT: Yeah.

JAD: Radiolab will continue in a moment.

ROBERT: As soon as I come up for breath.

-30-

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