- Hi. I'm Michael Corayer, and this is Psych Exam Review. In the previous video, we saw the basic steps in classical conditioning. And this shows how we take a neutral stimulus that doesn't cause a particular response, and then, by repeatedly pairing it with an unconditioned stimulus that causes an unconditioned response, we can turn that neutral stimulus into a conditioned stimulus, which now evokes a conditioned response. And so this process of learning this association between the previously neutral stimulus and the unconditioned stimulus is called acquisition. 

So for instance, in the case of the bell ringing and food presentation that is associated with Pavlov's work, we have this idea that once the dog has learned that the bell means that food is being presented, and then the bell causes the dog to salivate, we can say that acquisition has occurred. But this learning won't last forever. If we keep ringing the bell but never presenting food, eventually, the conditioned response will go away. And so this is a process called extinction. 

And this process of extinction doesn't happen all at once. So for instance, if I take one of the dogs, and I teach him to salivate to a bell, and then I keep ringing the bell without presenting food, eventually, the dog will stop salivating to the bell. We can say extinction has occurred. But it's not a complete extinction. Because if I take a break-- let's say I wait 24 hours or so-- this is what Pavlov did-- and then he came back and rang the bell again for the dog, he found that the conditioned response came back. And he referred to this as spontaneous recovery. 

And this indicates that the learning hasn't been completely forgotten. It's not gone from the dog's mind, right? He still has some association between the bell and the food, but it's been reduced. The intensity of that response has been reduced. But after a short break, it comes back. And if it's still the case that the bell is no longer paired with food, then eventually, the extinction will occur again, and the response will go away. 

Now, even then, it doesn't mean that the dog has completely forgotten this, because Pavlov found that if he retaught the dogs a particular association, they were able to learn it faster than dogs who hadn't been taught it in the first place. In other words, if I take a dog who's learned to salivate to a bell, and then I get extinction to occur by just repeatedly ringing the bell without food, eventually, the response goes away. But then, if I decide I want to teach this dog to salivate to a bell again, he'll learn it faster than some dog who's never been taught to salivate to a bell at all. So this idea that relearning can occur faster also indicates that there's some sort of lingering learning happening. So this idea that relearning occurs more quickly, the relearning is faster, for dogs that have previously learned a particular association. 

OK. Another thing that Pavlov found was that when he would-- let's say, he taught a dog to salivate to a particular bell. He could ring a different bell that was similar, but not the same, and the dog would also salivate. And so this is referred to as stimulus generalization. So the dogs are able to generalize and see that this bell is similar enough to some other bell that it will also evoke the conditioned response. 

So he did this with tuning forks, for instance. He would play a particular tone. He could teach a dog to salivate to a particular tone, and then he would play a different tone, and the dog would also salivate. But the response wouldn't be as strong. And as he got further away from the original note, the response would get weaker and weaker. 

But an interesting note here is that when he got to an octave, the dog would salivate more. The response would suddenly get stronger, more similar to the original stimulus. And this indicates that dogs hear octaves the same way that we do, right? 

So we describe a particular note that's an octave apart as sounding like the same note, right? So a C and an octave above that sounds like the same note, even though they're very different frequencies. And it appears that dogs have this same sort of recognition that octaves are the same note. 

Now, Pavlov also found that he could teach dogs to discriminate between similar stimuli. And so this is referred to as stimulus discrimination. And so if he taught a dog to salivate to a particular note by pairing it with food, but he had another note that he played that he never paired with food, if he did this enough times, the dog could actually learn to only salivate to one particular note, and not another note. 

So that would be an example of stimulus discrimination. The dog has learned that only this particular form of the stimulus means that food is going to be presented, whereas this other note that sounds similar but isn't the same doesn't mean that food will be presented. And with enough pairings, you can teach the dog to discriminate these similar stimuli. 

OK. The last thing that Pavlov was able to demonstrate was what's called second-order conditioning, or higher-order conditioning. And this means that he would introduce a new neutral stimulus, in addition to a previously conditioned stimulus. So what does that mean? 

So in the case of second-order conditioning, we already have some conditioned stimulus that causes some conditioned response. We ring a bell, and the dog salivates. So we've already taught something. 

And now, we're going to go to sort of a second layer of learning-- second-order conditioning. And that means we're going to introduce a new neutral stimulus before the conditioned stimulus. And then we're going to pair these repeatedly. So we have a new stimulus, then the usual conditioned stimulus, and the conditioned response. 

So for instance, Pavlov would do something like turn on a light and then ring a bell, and then the dog would salivate. And he found that if he did this enough times, he could actually get the dog to salivate to the light turning on. In other words, this neutral stimulus would now become a second-order conditioned stimulus, and that the light would cause salivation. 

And this is really interesting, because the light has never been paired with food. There was never a case where the light meant that food was coming. All that the light meant was that the bell was coming, and the bell meant that the food was coming. Right? 

And so it's sort of a layer away from the original unconditioned stimulus, and yet the dogs are still able to learn this association. The light means the bell. The bell means food. Therefore, they salivate to the light. 

OK. In the next video, we'll look at some other research on classical conditioning, and we'll also look at some of the constraints on classical conditioning-- the types of things that don't really work as well with this type of learning. OK. I hope you found this helpful. If so, please like the video and subscribe to the channel for more. Thanks for watching.