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Speaker 2: Welcome back to Coast to Coast George Noriy with Max Bennett,
Speaker 2: author of A Brief History of Intelligence, Evolution, the AI,
Speaker 2: and the Five breakthroughs that made our brains. What are
Speaker 2: the breakthroughs and what are the five breakthroughs?
Speaker 1: Max?
Speaker 3: Yes, so I will The five in order are steering, reinforcing, simulating, mentalizing,
Speaker 3: and speaking. So I'm going to go through each of those.
Speaker 3: But every breakthrough represented a set of new brain modifications
Speaker 3: that happen in evolution, and then it enabled a suite
Speaker 3: of new intellectual faculties, and they each built on each other.
Speaker 3: So let's go all the way back to the very
Speaker 3: first brain, all right, and we're back in six hundred
Speaker 3: million years ago. It's in a tiny little worm the
Speaker 3: size of a grain of rice. And in that whole ecosystem,
Speaker 3: most animals that were large, like cnm andes which are
Speaker 3: like coral, didn't move, so they didn't actually pursue food.
Speaker 3: The way they got food is they just waited for
Speaker 3: particles to go buy them, and then they would grab
Speaker 3: the particles out of the water. But our ancestor was
Speaker 3: the first creatures that actually found a way to move
Speaker 3: towards food and move away from danger. And what's so
Speaker 3: interesting is this first creature had no eyes, it had
Speaker 3: no ears, it had none of the standard sensory organs
Speaker 3: that we have today, and yet it could still navigate.
Speaker 3: And this is a big clue as to all of
Speaker 3: the foundational things about how brains work, and the way
Speaker 3: we know this is twofold. We can see fossil remnants
Speaker 3: of these early creatures, and there are modern animals that
Speaker 3: are quite similar to these early animals, like a modern nematode,
Speaker 3: which is a really really tiny little worm that has
Speaker 3: only about three hundred and two neurons in this entire
Speaker 3: nervous system. So how did this thing navigate without having
Speaker 3: any eyes or ears. Well, it was a clever trick
Speaker 3: called steering that these creatures us to navigate. And what
Speaker 3: happened is they had these tie little sensory neurons around
Speaker 3: their heads, and when a smell of something good increased,
Speaker 3: it would trigger them to steer in that direction. And
Speaker 3: when the smell of something good, like a food smell, decreased.
Speaker 3: The entire brain was based on this foundation of steering,
Speaker 3: towards good things and steering away from bad things, which
Speaker 3: means the foundation of brains is based on the idea
Speaker 3: of classifying things in the world into good and bad.
Speaker 3: And so that was the very first brain. There was
Speaker 3: a whole suite of really interesting things that came with this.
Speaker 3: In that brain, the standard use of dopamine, serotonin, and
Speaker 3: adrenaline emerged, which has a really interesting relationship to our
Speaker 3: modern brains. So there's a whole long journey of how
Speaker 3: we've tried to understand what dopamine does, for example, and
Speaker 3: so for a long time people thought dopamine was the
Speaker 3: pleasure chemical, and has been a lot of research that
Speaker 3: shows if you stimulate dopamine neurons in a rat, for example,
Speaker 3: every time it pushes the lever, the rat will endlessly
Speaker 3: push the lever. And that makes people think, oh, it
Speaker 3: must be the pleasure chemical.
Speaker 2: They want it, they want more, Yeah.
Speaker 3: They want more. Right, It turns out this guy Ken
Speaker 3: Berage did some incredible study that revealed that dopamine is
Speaker 3: actually not pleasure and this goes all the way back
Speaker 3: to the first prance. But his experiments were the following
Speaker 3: He said, okay, well, we actually know that rats make
Speaker 3: very specific facial expressions when they enjoy food. They smack
Speaker 3: their lips and they make a gaping face when they
Speaker 3: don't enjoy food. And so if we give these rats
Speaker 3: a ton of dopamine, do they actually show more pleasurable
Speaker 3: lip smacks? And the answer is no, they will eat
Speaker 3: a lot more, but if anything, it looks like they
Speaker 3: don't like the food anymore. And in fact, if you
Speaker 3: remove dopamine so they have no dopamine in their brain,
Speaker 3: they'll stop eating. But if you put food in their mouths,
Speaker 3: they'll enjoy the food. That's what does this mean. It
Speaker 3: means dopamine is not about pleasure. It's about craving. Dopamine
Speaker 3: is about pursuing things that we want. It's not about
Speaker 3: the actual enjoyment of things when we get it. Let's
Speaker 3: go all the way back to a nematode. Now, what
Speaker 3: are the dopamine neurons In a nematode. There are little
Speaker 3: neurons that stick out of their head that detect the
Speaker 3: presence of food around the animal. And then there's another
Speaker 3: set of neurons and the nemotod's throat that are serotonin
Speaker 3: neurons that detect when it's actually eating food. So in
Speaker 3: the very first brain, dopamine was the signal for good
Speaker 3: things are nearby, and serotonin was the signal for good
Speaker 3: things are actually happening. And that basic template between these
Speaker 3: two neuromodulators exists all the way throughout the animal kingdom,
Speaker 3: and it's served a whole purpose for steering because and
Speaker 3: you see this in a roomba. I don't know if
Speaker 3: you know what a rumba is, the little robot vacum, right,
Speaker 3: So rumba's work very similarly to the first frame. So
Speaker 3: there's something called dirt detect in a roomba. When a
Speaker 3: room but passes a patch of dirt, it assumes that
Speaker 3: it must be nearby patches of dirt, so it changes
Speaker 3: its repertoire. So if it passes a little piece of dirt,
Speaker 3: it starts turning randomly in the local area because it
Speaker 3: predicts that if there's a little dirt in one location,
Speaker 3: there's probably dirt nearby. This is exactly what dopamine did
Speaker 3: and does nematode brains. If it detects a little bit
Speaker 3: of food, it floods the brain with dopamine, which triggers
Speaker 3: it into an emotional state of what could be called
Speaker 3: exploitation when they start turning around looking for food for
Speaker 3: a while, so dopamine levels drop and then it keeps
Speaker 3: going elsewhere. So dopamine is this initial seeking chemical. Serotonin
Speaker 3: is the statiation chemical, it makes them stop and rest,
Speaker 3: an adrenaline is this big fear chemical. So the basic
Speaker 3: template of emotion and stress and categorizing the world into
Speaker 3: good and bad with all present in the steering brain
Speaker 3: of the very first animal that was break through one.
Speaker 2: Number two, I can keep going ye five.
Speaker 3: So moving forward fifty million years into the Cambrian period,
Speaker 3: our ancestors evolved into a creature that was most similar
Speaker 3: to a modern fish, which were the first vertebrates, and
Speaker 3: they now had eyes lends shaped eyes, so they looked
Speaker 3: very similar to modern fish. They had ears, they had
Speaker 3: a vestibular system, meaning they could detect direction, and so
Speaker 3: you know, they had the basic template of what we
Speaker 3: think about when we look at a fish. And most
Speaker 3: of the creatures in the Cambrian period were arthropods, so
Speaker 3: they were huge insect like creatures, and our ancestors were
Speaker 3: very humble, tiny maybe one to two inch long fish
Speaker 3: in this whole world, but if you looked in their brain,
Speaker 3: you would see a brain that has most of the
Speaker 3: same structures as a human brain, which is exactly what
Speaker 3: we see when we look at modern fish, which is
Speaker 3: kind of mind blowing to realize that even in a
Speaker 3: tiny fish brain, you can see most of the same
Speaker 3: brain structures as a human brain. And so the question
Speaker 3: is what does this brain do. Well, it's a really
Speaker 3: cool story that is connected to AI where it goes
Speaker 3: a little bit back to dopamine, where I'm gonna tell
Speaker 3: a little bit of a story of AI, and then
Speaker 3: I'll connect it back to brands. So in the nineteen fifties,
Speaker 3: people have this grand idea of what if we could
Speaker 3: train a neural network with reinforcement learning, In other words,
Speaker 3: we just tell it when it does something right, and
Speaker 3: then over time I should learn the right decisions to
Speaker 3: keep doing the thing that quote unquote is right. And
Speaker 3: perhaps we could teach it to play chess if we
Speaker 3: just say, hey, AI system, play human in chess, and
Speaker 3: when you win, I'll give you a reinforcer. When you lose,
Speaker 3: I'll punish the system, and if you do it enough times,
Speaker 3: eventually should get good of chess. And this guy, Marvin
Speaker 3: Minsky tried this, and it didn't work. And the reason
Speaker 3: it didn't work is because of something called the credit
Speaker 3: assignment problem. When you win a game of chess, which
Speaker 3: previous moves should get credit for being good? You don't
Speaker 3: know because it could have been the first moves that
Speaker 3: were really good. It could have been moved in the middle,
Speaker 3: it could have been moved at the very end. And
Speaker 3: so when you get a reward when you win a game,
Speaker 3: it's actually hard to know what actions should actually be reinforced.
Speaker 3: So this guy, Richard Sutton, came up with this really
Speaker 3: clever strategy, which is how all modern reinforcement learning systems work.
Speaker 3: In your self driving car, that's using the exact same
Speaker 3: technique he discovered, which is then called temporal difference learning,
Speaker 3: where the reinforcer is actually when you think the world
Speaker 3: just got better. In other words, when you're playing a
Speaker 3: game of chess and you do a move and you realize, oh,
Speaker 3: the thing I just did increased my likelihood of winning
Speaker 3: by a lot, that's when you get reinforced. And so
Speaker 3: when we look in fish brains, we actually see exactly
Speaker 3: this algorithm being implemented, which is it has an expectation
Speaker 3: of future rewards and it's reinforcing itself again with dopamine
Speaker 3: when things seemed to be doing better. This all happens
Speaker 3: in the structure called the basal ganglia. So breakthrough two
Speaker 3: is reinforcement learning. It was this ability to learn through
Speaker 3: trial and error, and we see this in fish all
Speaker 3: the time. You can teach a fish to do very
Speaker 3: very clever things through error. You can teach fish to
Speaker 3: jump through hoops. You can teach fish to remember random
Speaker 3: shapes of animals and they'll run away from them or
Speaker 3: they run towards them. So reinforcement learning was break through two.
Speaker 3: We go forward a bunch further, all the way to
Speaker 3: about one hundred million years ago. Our ancestors were early
Speaker 3: mammals and they resemble most resembled in early creature that
Speaker 3: would look like today's squirrels, and they lived in a
Speaker 3: world surrounded by dinosaurs. They were very low on the
Speaker 3: totem pole. They were hiding in burrows. The world of
Speaker 3: sinus our life and our little mammal ancestors evolved a
Speaker 3: new brain region called the neocortex, and the neocortext gave
Speaker 3: them a very remarkable ability, which is to imagine the
Speaker 3: world as it is not in other words, to simulate things,
Speaker 3: so a mammal can imagine futures and remember paths and
Speaker 3: can consider alternative decisions. You see this in rast today.
Speaker 3: So if you put a ratinum aze and you record
Speaker 3: neurons and a hippocampus which has these things called place cells,
Speaker 3: you can literally wash a mouse imagine going down different paths,
Speaker 3: and you can watch it imagining eating one type of
Speaker 3: treat versus another before it makes a decision, which is unbelievable.
Speaker 3: We can literally go into mouse brains and see them
Speaker 3: imagining things and so simulating. It's this incredible ability to
Speaker 3: not only learn by actual trial and error, but to
Speaker 3: learn by vicarious trial and error. In other words, I
Speaker 3: can learn before I take an action. I can imagine
Speaker 3: doing things and then decides to them. It's an incredible
Speaker 3: break forward, and this is one thing that's really missing
Speaker 3: in aisystems, which has important consequences. Break Through four emerge
Speaker 3: in early primates something called mentalizing, which is the ability
Speaker 3: to think about thinking, and this is another key thing
Speaker 3: missing in AI systems. So if you go into a primate,
Speaker 3: there's some cool stories where primates trick each other. So
Speaker 3: one famous one is this guy Mlo Menzel was trying
Speaker 3: to teach a chimpanzee to find locations of food. And
Speaker 3: you would place a little piece of a treat under
Speaker 3: a rock or in a bush until and show one
Speaker 3: champanzee in this group where to find it, and that
Speaker 3: chimpanzee would very easily find the tree. But then he
Speaker 3: noticed something that he did not expect to find, which
Speaker 3: is when Belle, one of the chimpanzees, ran to the tree,
Speaker 3: she would share it with other chimps in the group.
Speaker 3: But then what's started happening is Rock, the top chimp,
Speaker 3: would take the treat from her for himself. He was
Speaker 3: kind of a jerk. So what Belle started doing is
Speaker 3: she wouldn't go to the tree until Rock was not looking,
Speaker 3: so she was trying to vent him from seeing it.
Speaker 3: But then Rock, in exchange, began looking away, pretending he
Speaker 3: wasn't paying attention until Bell would go to the tree.
Speaker 3: Then he turned around and run towards it. So then
Speaker 3: Bell started trying to lead Rock in the wrong direction
Speaker 3: and then run back. So the cycle of deception and
Speaker 3: counter deception is really amazing evidence that chimpanzees and other
Speaker 3: primates we see the same thing can actually think about
Speaker 3: each other's thinking, because in order to do that, she
Speaker 3: needs to understand well, I can trick rock into thinking
Speaker 3: the rock is not here or the treat is not
Speaker 3: here if I bring him in the other direction or
Speaker 3: if I look away. So mentalizing is this really amazing
Speaker 3: feat that emerge in primates. It comes from variety of
Speaker 3: brain structures like the granular prefrontal cortex, and that's a
Speaker 3: really crucial thing missing in the A systems. For reasons,
Speaker 3: I can go into and then break through five with
Speaker 3: early humans was language. And language is only really possible
Speaker 3: because the mentalizing, because when we're talking, when we talk
Speaker 3: to each other, we're always inferring what each other mean
Speaker 3: when we speak to each other. So this is a
Speaker 3: big problem with AI, where when we say things to them,
Speaker 3: if they don't know what we mean, there's potentially dangerous
Speaker 3: consequences which I can talk about. So anyway, those are
Speaker 3: the five breakthroughs very fast. I can go into any
Speaker 3: of them in much more detail. But steering, reinforcing, simulating, mentalizing,
Speaker 3: and then speaking.
Speaker 2: Do other creatures have a language? I've long suspected that
Speaker 2: some animals or insects have an ability to communicate with
Speaker 2: each other, But is it a language or something else?
Speaker 3: Very very good question. So all creatures communicate with each other.
Speaker 3: I mean even single cell bacteria sends chemical signals to
Speaker 3: each other and will share genes when they need to
Speaker 3: share genes to help each other out. And we know
Speaker 3: for a fact that monkeys signal each other. They have
Speaker 3: Some monkeys have certain signals that mean eagle, which make
Speaker 3: all of them jump to the forest floor. They have
Speaker 3: other signal notes that means snake that leads them all
Speaker 3: to run to the tree tops. So we know there
Speaker 3: are signals throughout the animal kingdom. But language is unique
Speaker 3: on two fronts. Language contains what's called declarative labels. And
Speaker 3: the declarative label is saying you can point to an
Speaker 3: object and say that is a cup, and now on
Speaker 3: your head, you know the thing is called cup, an
Speaker 3: arbitrary sort of symbol. And then we have grammar. That's
Speaker 3: the second thing. I can start assembling these symbols into
Speaker 3: novel phrases, like the words I'm saying right now. And
Speaker 3: it's really controversial whether any other animals do that, which
Speaker 3: is assigned symbols and phrase them into novel ways. There's
Speaker 3: been many studies trying to get chimpanzees and bonobo's to
Speaker 3: do this with pretty lackluster results. So you know, there's
Speaker 3: still emerging studies and other animals. But for the most part,
Speaker 3: it seems like language, at least the extent to which
Speaker 3: we use it, as pretty unique to humans.
Speaker 2: Pretty dramatic, isn't it amazing?
Speaker 1: Oh?
Speaker 3: The language was mind blowing. Language was the first time
Speaker 3: when we could learn from each other's imaginations. Think about
Speaker 3: how powerful that is. I can go before language. If
Speaker 3: someone in our in our primate group ran across a
Speaker 3: you know, the forest, to a different location and saw
Speaker 3: that a red snake fiting them was really bad and
Speaker 3: it's really dangerous, they could never share that information that, hey,
Speaker 3: avoid red snakes. It was impossible. But with language, I
Speaker 3: can share, Hey, this thing happened in the past, and
Speaker 3: now I'm going to give you that information about it.
Speaker 3: Or together we can plan a hunt. I can say, hey,
Speaker 3: let's go to this location. You go left, I go right.
Speaker 3: When I whistle three times, we're going to start hunting together.
Speaker 3: And all that type of coordination was not possible with
Speaker 3: that language. Unbelievably powerful.
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