The second learning mechanism is known as classical conditioning, and a behaviorists would describe this as the learning of an association between one stimulus and another stimulus. This mechanism can best be illustrated through a famous experiment by the Nobel Prize winning physiologist Ivan Pavlov. Pavlov won his Nobel Prize for studies on the physiology of digestion, and to explore this, he needed to collect saliva from dogs and an apparatus for doing so. But he came to notice that of course the dog would produce saliva in response to the food, that was expected. But he observed that the dog would also start to produce saliva when a person carrying the food walked into the room and when the dog saw the dish. Later on, to explore this, Pavlov would ring a bell and then get the dog the food. After repeated pairings of this sort bell, food, bell, food, bell, food, the dog will start to salivate at the sound of the bell. This is really cool. I mean, we can talk about the details and what this experiment means, but it's a wonderful example of scientific serendipity of chance, how a scientist looking at one thing can discover another and be smart enough and clever enough to notice wow there's something really interesting going on. It's one of a million reasons why science is incredibly cool. So, here's the logic of classical conditioning, along with the vocabulary people use to describe it. You start off with a neutral stimulus. In the case of Pavlov's experiment, it's a bell. So the bell evokes no responses, it's neutral. The dog hears the bell and goes whatever. You also have an unconditioned stimulus and unconditioned response. In this case, it's the food and the saliva. The idea is that prior to the learning, this already exists, either it's innate, it's builtin, or it's been learned in the past. But regardless, the dog starts off with a saliva response to the food. So, you have two sorts of things. You have the bell, a neutral stimulus that gives rise to no response, and the food, an unconditioned stimulus which gives rise to an unconditioned response. Then you have conditioning, our learning. In conditioning, what you do is you put together the bell and the food. You put together neutral stimulus and the unconditioned stimulus. The unconditioned stimulus will give rise to unconditioned response and a neutral stimulus will be paired with the unconditioned stimulus. The cool thing about this is that over time, if you have these repeated trials going together, soon, the bell will go from being a neutral stimulus to being conditioned stimulus and give rise to the conditioned response. So, imagine you go to a dentist's office and it's your first trip to a dentist's office, and when the drill hits your teeth, it's painful and you flinch. Also, the drill makes a sound, a whine. Now, originally, this whine is a neutral stimulus like the bell to the dog. You here the whine, you go 'whatever'. No response at all. Well, the pressure of the drill against your teeth is an unconditioned stimulus giving rise to an unconditioned response of flinching or pulling back or pain or whatever. Conditioning then will happen because whenever the dentist presses drill against your teeth in a painful way, you hear the sound of whine of the drill. Through the magic of classical conditioning, what will happen over time is that as soon as you hear the whine of the drill even if it is not against your teeth, you'll flinch and drawback. So, the logic of classical conditioning is that repeated pairings of a neutral stimulus and unconditioned stimulus transforms a neutral stimulus into a conditioned stimulus, giving rise to a conditioned response. Behaviorist talk about reinforced trials. A reinforced trials are trials when the conditioned stimulus and unconditioned stimulus are brought together. The bell and the food, the whine of the drill and the drill itself, and this increases the connection. This is how learning takes place. There is also unreinforced trials. An unreinforced trials when the conditioned stimulus happens without the unconditioned stimulus, and this decreases the connection of learning. Gradually, the connection goes away. Imagine you were to ding the bell at Pavlov's dog but not providing food so dog would produce saliva, then you do it again and again and again and again. Over time, the dog will produce less and less saliva. If you would here the whine of the drill but experienced no pain over and over again, you gradually come to respond to it less. The idea is that the world changes. You imagine two things that are connected, you should produce the same response. But they could become unconnected, and you should also be flexible enough to learn not to produce the same response, and this is what's called extinction. So, classical conditioning has considerable range of application. You can use the methods of classical conditioning to teach things to all sorts of animals, not just dogs, and cats, and chimps, and horses, and so on, but even animals like crabs, and fish, and cockroaches. Just about any creature can learn the relationship between two different types of stimulus. So, stimulus that originally didn't evoke any response, like a sound or a flash of light, can come to evoke a sort of reaction. When it comes to people, classical conditioning has been argued to play a role in all sorts of things. So, for instance, you could imagine playing a role in the acquisition of phobias, something that originally had no import. You weren't afraid of it at all, like say a dog. You could become afraid of it if it became associate of a painful experience. You could imagine along the lines is something like Clockwork Orange, the movie in which our main character is tortured, and in the midst of his tortures, he hears classical music, and the classical music becomes associated of his suffering. So soon, classical music becomes incredibly aversive to him. On a brighter side, classical conditioning is the logic underlying some treatments of phobias. So, imagine you are afraid of snakes, you're deathly afraid of snakes so much so that it is messing up your life, well, one sort of treatment would be, and this is known as a systematic desensitizations, is exposed you to pictures of snakes or images of snakes in kind of a safe way while pairing these with relaxation techniques, or in some cases, just drugs they gave you to relax. As a result of this, over time through classical conditioning, these stimuli come to evoke the same response of relaxation that the drug has or the relaxation technique has. So, stimuli that were originally aversive can come to have different connotations. One can see classical conditioning to a hunger reaction, so we're not Pavlov's dog. But in some way, we are in that certain times of day or certain experiences evoke hunger, not because they are intrinsically the sort of things that evoke hunger, but because they become associated with hunger. If you walk past a favorite restaurant or a TV commercial, it's showing images of things like food wrappers or things that are associated with favorite foods you have can make you hungry or take various addictions. You may discover you have a craving for a cigarette or a drink or some heroin right when you put into a situation, which is typically associated with cigarettes or alcohol or heroin. Through classical conditioning, our appetites can be evoked in strange ways. This has been taken by some to provide their lines of a theory of fetishes, where people are sexually aroused by things like footwear, and you could imagine a story where you are achieving sexual satisfaction through a conventional way, and also in your eyes fall upon a pair of shoes. These two things become associated through the magic of classical conditioning, where say to pleasure of orgasm gets associated with those shoes, and now shoes become a conditioned stimulus evoking into conditioned response of sexual interest. Now, that's a crazy theory. I mean, for one thing, it doesn't explain why some things like shoes are the target of fetishes and sexual interest while other things that you might look at during sex like clocks or ceiling fans or pillows don't become the object for sexual fetishes. For another thing, for something to become learned through classical conditioning, you need repeated exposure, and it's hard to imagine how that's going to happen. But nonetheless, people have argued that classical conditioning has some role in sexual delight and sexual satisfaction. In fact, one treatment for pedophiles, controversial, but one treatment for pedophiles would be training them to have control fantasies during masturbation, to shift the association of sexual pleasure away from they dominance and violence in children to more appropriate and more moral sorts of interactions. So, what is classical conditioning? I have described how it happens and the phenomena, but what goes on in it? The idea is it's an adaptive mechanism that gives you sensitivity to cues that an event that is about to happen, and the purpose of the sensitivity is that it allows you to prepare for that event. So, what's really going on in classical conditioning is we're sensitive to cues to something to allow us to prepare for that something. This elegantly explains two very interesting things. One is, what's the optimal timing between the conditioned stimulus and the unconditioned stimulus? Say the conditioned stimulus would be the bell and unconditioned stimulus would be the food, or the conditioned stimulus would be the drill and unconditioned stimulus would be the pain and by drilling and the sound of the drilling, that sound. It turns out it's actually not best when they're simultaneous, rather we learned the connection best when the conditioned stimulus comes immediately before the unconditioned stimulus. This makes sense if you think that neurological system underlying classical conditioning is built so that you can prepare and anticipate. Moreover, the conditioned response is often preparation for the unconditioned stimulus. So, consider why would a dog fill his mouth with saliva when it hears the bell? Well, that's what you do when you are about to get food. Why would you flinch when you hear the whine of the drill? Well, because that's what you do when you are about to get poked. So, classical conditioning is in some way a mechanism of preparation and an adaptive and clever interesting way for the mind to have evolved to deal with the world and how to cope best with it.
