I want to walk you through some of the laboratory research of behavior inhibition. To give you an idea of how we acquire this information about how we engage in these complicated behaviors. And I never quite know whether to talk about us engaging in behavioral inhibition or not engaging in it because of this double negative type of thing. Let's begin. And the first experiment I wanna talk about took place in the laboratory of Byron Campbell at some little university down the road a ways here, Princeton University, back in the 1960s and 1970s. So all of this research that I'm going to talk about, three pieces of research, took place beginning more than 50 years ago but it's pretty much withstood the test of time and it provides a good example of how a couple of these research stories have kind of gone around and reached a conclusion and that's why I'm presenting it here. But the little picture that you see up here in the center is a picture of a litter of baby rats. And they are remarkable little creatures. Well, first of all it's remarkable because you can't believe how many babies that mother rat had. [LAUGH] It might be 10 or 15 or 20 little babies come spewing out. They are very, very undeveloped. A baby rat has no fur. Its eyes have not opened yet. Its ears have not opened yet, but it knows how to find milk and suckle and if you wonder if the little baby rat has been successful in nursing it's mother, all you have to do is hold it up to the light and look at the milk in the stomach, because you can see right through them. Just remarkable little creatures. And yet within their first week of life they are are capable of performing what's technically called an active avoidance response. You have to make some accommodations for them, but they're really as good learning that as adult rats are and an active avoidance response can be something as simple as being put in a little chamber here. A light comes on, five or ten seconds later a little bit of electric shock is delivered. And you have to scoot over here to get away from it. After a few trials the light comes on and this little undeveloped creature moves over here and avoids the shock, comes equipped to make that kind of an analysis of the environment. If you do a different kind of experiment, an experiment called passive avoidance, where for example if the little rat comes over here and touches this it receives a little electric shock so all it has to do, and this seems simpler to me. All it has to do is not do that. It's like the old joke. Hey doc, it hurts when I raise my arm like this. And the doc says, well, don't raise your arm like that. That's a passive avoidance response, and the little critter just can't get the hang of that. So two superficially, very simple tasks. One of them it can learn as well as an adult, and the other, it can't learn. So you wait a while. You wait until the rat is about 28 days old. And now you've got yourself a real nice little creature here. Its eyes are open, its ears are open. Its got fur. They run around they jump on each other. They do all kinds of athletic types of things. And obviously, they can still do that passing avoidance task. But now, if they walk over and touch this and get an electric shock, they stand back and say, I'm not gonna do that anymore. So now, they can learn to not do something that gets punished, and they can learn to not do something that is no longer rewarded. So during that first month, their eyes open, their ears open, they grow fur, and they develop the ability to not do things that they're not supposed to do. So these little rats at 28 days, they have a whole different time scale than we do. I don't know, I would probably put them in high school, at about 28 days. So they have a much different scale of life than humans do. Okay so here's one little piece of the puzzle, that says there are differences. And we call them cognitive abilities, that there are differences in the rat's cognitive abilities. That some things are already developed either at birth or very shortly thereafter, and other things take a while. Other things take a while. Another piece of research took place right here at Rutger's University. A researcher named Peter Carlton, who was in the Rutgers medical school. For those of you who've been kinda watching what's happening at Rutgers here, we are in the process of getting a medical school. How cool is that? Well it's kinda cool, but the kind of sad thing is that we had one. We had one back in the 60s, and the governor then took it away, and now we've got a governor giving it back, but don't get me started on things like that. Anyway, Peter Carlton was also interested in this phenomenon of behavioral inhibition, partly because he talked to the guy down the street about this. But he took a different approach using mostly adult rats, and had a number of different measures of behavioral inhibition. Some of them were the type of touching something and getting punished, and you don't do that anymore. Others were learning to do some response that's rewarded, rewarded, rewarded, rewarded, and now you stop rewarding it, how quickly does the rat stop doing that? Or how quickly does it learn that if I go this way, it doesn't work anymore but if I go this way it does? The position habit reversal. So we had a whole battery of behaviors, each taking a little different measure, a little different assessment of the ability to withhold a response. And what he found was that you could give a whole bunch of different kinds of drugs to these rats and it would make no difference whatsoever in that type of behavior. But if you gave a drug that blocked the neurotransmitter acetylcholine, then the rats were greatly impaired in their ability do something like passive avoidance. They were still perfectly good at doing active avoidance, but they couldn't do passive avoidance. So this then showed, or provided a clue, for the types of neurons in the brain that are doing this. A third study took place at the University of Chicago. All of these at about the same time. And one of the people involved in that, was a young graduate school researcher named Lynn Hamilton. But that was a long long time ago and McCleary was working, trying to figure out which parts of the brain were doing this. And also had a set of several different measures of behavioral inhibition. And one of the interesting thing is that all three of these experiments had multiple measures of behavioral inhibition, but they didn't really overlap much. So they were all different ways of looking at it, performing a kind of complex set of experiments here. And what McCleary found is that if you damaged this part of the brain, it would have no effect on it. If you damaged this part of the brain, no effect. This part of the brain no effect, but if you went in and damaged certain parts of the limbic system that we've already talked about then all of a sudden you would have subjects that were unable to withhold a response that was punished or not rewarded. Now, this is how science works. This is how we gradually learn how the world around us makes sense in a way that it doesn't necessarily make sense just by sitting and thinking about it. So, what we have here is a set of experiments, when you put them all together, that tell us when this ability to withhold a response occurs. What kind of neurons inside the brain are doing it, and where those neurons are located, and we have a convergence of evidence. There are thousands of stories like this in the scientific literature, and they all look like this. When we get to the point where we can say we actually know something about this, it's because we've collected data and we know the where, what and when of how it works by doing controlled, carefully executed, carefully measured experiments. What about people? Up here in the corner we have a little infant. What have you learned in this course about infants? What are they? Stupid. Yes. Stupid, stupid, stupid. Yeah, they are kind of stupid in some measures. But they come with a good set of tools to get over that. And some of the work has been done right here at Rutger's University by a professor Roby Collier, who has like many other developmental psychologists, developed the skill of asking these babies questions that they can answer. And one of her famous experiments is to show a baby a mobile. And this baby can be just five or six weeks old, five or six weeks old. And if you just go in and say, [SOUND] and ask the baby, do you remember that mobile that I showed you yesterday? They might burp, but they're not going to give you any real information. But if you design an experiment where they can look at the mobile and you can watch their eye movement, or you can have them kicking their foot to make the mobile jiggle, and then you can change one of the elements of that mobile. What you can find out is these little guys can look at a mobile that has six or eight different brightly painted figures on it, and a month later, they can remember that well enough that if you change one of the elements, they respond differently. So yeah, they can see, they can Interact, they can remember. My wife Robin Timmons worked in that lab for her dissertation and was able to show that babies can learn that one set of events can be controlled by the hand. Another set of events controlled by the foot. And they can remember that for long periods of time. So, we can learn a lot about the behavior of these babies. They have a lot of tools to learn about the world around them. But we are reluctant to let them use those tools. We don't give them matches and sharp objects. We don't let them investigate the physics of rolling down stairs. There's just all sorts of things that we don't let them do. We protect them 24 hours a day because they're really not very good at the things that adults do in the environment. They grow up, they get a little older, and now all of a sudden they're pretty good at doing stuff. Pretty good. They can run and jump, can't skip for a while. They're learning to talk. Just an amazing, amazing rate. Many of you have take a foreign language course as high school students or college students. You guys are so pathetic, that you don't learn nearly as many words per day as this little person right here. They are just soaking it in, learning the language. They've got good reflexes, good vision, good hearing, and yet we don't let them have the experience of driving a car. We don't let them drive cars. I asked a class a few years ago, well why not? Some students says because their feet can't reach the pedals. But that's not the real reason. It's because we don't want them out there driving a car, they would be dangerous. Little bit older here. And this little guy, I'm sure with a little practice, can just beat me into oblivion on a computer game if it was based on quickness of reaction time and things like that, or on a hearing test, or on a vision test. Just remarkable skills, still don't let them drive cars. This little guy here, it's not Professor Ogilvy even though he is holding somebody else's fish there. But anyway, pretty responsible kid. At that age, you would let that kid stay home alone, for a while. You would let him walk to school, for a few blocks. You would give him the responsibility to go into a store and buy something. You would leave him with a smaller child for awhile as a babysitter. No problem. Don't let him drive, because he would do dangerous things. Do dangerous things. Oh and look at this, the dawning of a new age. A little digital device in her hands. And might start to let her drive a little bit under supervision. But again, under carefully controlled supervision. So if you think about all of these things, and now we can come up to you people in a year, or two, or three. We let you drive, and we let you go off and fight wars. We try not to let you drink alcohol. It doesn't work very well, we try. You're smart, you've got good reflexes, you've got just a whole host of skills and knowledge and everything, but the fact of the matter is, you people engage in behaviors probably on a regular basis that would just scare the living crap out of me. And I'm a little bit more like Justice Ginsburg, conservative in many of my behaviors. And what all of these things have in common with the rats down at Princeton University, is that we very quickly develop skills that allow us to do all sorts of complicated things. We are slow to learn to withhold responses that are either punished or non-rewarded, or might be punished or non-rewarded. So, just like the rat that comes equipped almost on day one with the ability to do active avoidance types of responses. It takes it 28 days to reach near adult levels of the ability to not do things. We come equipped kind of slowly, but we come equipped early on with the ability to do things, and make associations, and learn all kinds of complex things about the world around us. But it takes us at least 30 years to reach kind of a plateau of behavioral inhibition. And it may take another 30 years to reach what some researchers call wisdom, to reach the ability to really carefully, systematically analyze complex possible future events, and behave accordingly.
