[SOUND] In this section, we'll consider the nature of control outside of the bilingual context. And we'll think about development, and how control and development work together. Cognitive control involves the brain. I like to think about an example of the dog next door. So, the dog next door frequently barks, especially when I take out the trash or if I'm going to leave my car in the driveway and not park all the way in the garage. Oftentimes, the dog will bark. And I always wondered why the dog barks. I mean, if it were a person and the person saw you, probably the person would say hello. And at some point, they might be doing something and realize, oh, that's the neighbor, and they wouldn't think anything of it. But the dog continues to bark as if I were a stranger. Now, of course, some thoughts have crossed my mind about how to silence the dog. But of course, I realized very quickly that those thoughts are not appropriate since it's not my dog. And even if it were my dog, that wouldn't be appropriate either. So, I have to simply imagine that the dog is not barking, all right? And to do that requires me to imagine something that's not true, to imagine that there's silence when, in fact, there's barking. Now, the ability to do this and to imagine something that's not true is perhaps one of the hallmarks of humans, and it's reflected in the size of the prefrontal cortex. So if we look across species, and we look at cats or monkeys or chimpanzees or dogs, and we move up to humans, consistently what we see is that the prefrontal cortex gets larger and larger. And when we look carefully at the difference in the prefrontal cortex between a dog and a human, we see that the difference is quite vast. And that, in fact, that might help to explain why my neighbor's dog continues to bark even though I've lived there for almost 11 years now. A few decades ago, some researchers argued that the difference between chimpanzees and humans was purely due to environment, that if we took a chimpanzee and put him or her in a human environment, and raised that chimpanzee as a human, that he or she would act like a human would. So in fact, that's not what happened. A group of researchers decided to raise a chimp, and they called him Nim Chimpsky. It was a bit of a poke at Noam Chomsky, a famous linguist who argued that humans had a language acquisition device. And their idea was that if they raise this chimp in a human environment, the chimp would actually produce language just like humans would. And that's not what happened. The chimp essentially grew up as a human, and interacted and had a family and a brother. And they began to find that, in fact, the brother appeared to actually imitate Nim much more than Nim imitated his brother. Humans are very good at imitation, and so the human brother began to actually act like a chimp, which is interesting. And Nim had a very difficult time, obviously, with language because the vocal apparatus is not set up to produce language. And secondly, trouble with social interaction. Nim had a really hard time not being territorial, so any kind of threat to his brother could be punished physically, and Nim couldn't understand that that was not appropriate within human culture. So eventually, Nim was placed into a colony, and he grew up with other chimps and lived with them the rest of his life. But interestingly, everybody always felt that Nim understood humans the best, better than any other chimp. So there was a clear effect of the environment, a clear effect on Nim, and how he interacted with humans. But he was never human although many people suggest that maybe he thought he was a human. But he was not. So the question is, what held him back? Why couldn't Nim become like a human? And some of those answers have to do with cognitive control. We can consider the connections between different regions in the prefrontal cortex and posterior regions in parietal and temporal cortices. If we look at the dorsolateral prefontal cortex, we see that that actually connects to the inferior parietal cortex. And if we look at another region, the ventromedial cortex, we can see that that area connects to the inferotemporal cortex. These two posterior regions, the inferior parietal lobule and the inferotemporal cortex, handle different types of information. The inferior parietal cortex is involved when location information is necessary, and the inferotemporal cortex is involved when identity of an object is necessary. Now obviously, we do all of these in parallel, and we can see where something is and what it is at the same time. But these are done through these different tracks, and these different areas interconnect two distinct frontal cortices, ventromedial to inferotemporal, dorsolateral to inferior parietal cortex. The difference in these frontal areas can be seen in different species of primates. So, orangutans, who are relatively solitary, but have very good tool use, have underdeveloped ventromedial cortices. And the idea is that this ventromedial area is underdeveloped, and that these connections to the what system, right, to the object or the identity system, are crucial for social interaction. Hence orangutans have less social interaction, but they have a relatively well developed dorsolateral to inferior parietal connection in areas. And so, their tool use is quite good. If we look at the dorsolateral prefrontal cortex and we look at chimpanzees and orangutans, we see that, in fact, chimpanzees and orangutans have larger dorsolateral prefrontal cortices than bonobos do. And interestingly, bonobos are the only one of those three that doesn't construct tools. So the suggestion is that the ability to construct tools involves the dorsolateral prefrontal cortex and its connections to the inferior parietal lobule, and that when this area is smaller as it is in bonobos, you'll get less tool construction. Humans have both the ventromedial and the dorsolateral prefrontal cortex very well developed. And the fact that as humans, we have this vast area devoted to either tool construction or to social interaction allows us to perform very complex types of calculations. Nim didn't have nearly as much real estate in his prefrontal cortices and ventromedial prefrontal cortices. Because of these actual biological limitations, he was unable to do the types of computations that humans commonly do. And in some ways, that held him back and didn't allow him to become fully human.
