Classical conditioning: Extinction, spontaneous recovery, generalization, discrimination

We've talked about how my guinea pig inherently loves carrots and responds to them by being excited. We said that the carrots are the unconditioned stimulus because they naturally elicit the behavior of her being excited. So excitement in this case is the unconditioned response to carrots. Now in order for me to give her a carrot, I have to open my refrigerator door. But since my refrigerator door is broken, it makes a loud popping noise whenever it's been opened. So the noise of the refrigerator door was the neutral stimulus because on its own, it didn't initially make my guinea pig excited. But since my guinea pig heard that popping sound every time I went to get her a carrot, the popping sound was paired with the presentation of a carrot, and eventually when she heard that popping sound, she acted excited, as if she was about to receive a carrot. And even if I just to open the refrigerator door to make myself a snack, she would respond that same way. Since now she responds to the sound of the refrigerator door in the same way she responds to a carrot, the sound of the refrigerator door is no longer a neutral stimulus. It's a conditioned stimulus. And when something responds to a conditioned stimulus, that response is referred to as a conditioned response. But I started to notice an interesting phenomenon. Sometimes I would see her acting excited when I would open my desk drawer, which also happens to make a loud popping sound because it gets stuck a lot from having so many papers and things inside of it. While the two popping sounds have their differences, to my guinea pig they sounded similar enough that the sound of my desk drawer opening was able to cause excitement in her almost as much as the sound of the refrigerator door opening. And the term for this is generalization. A generalization is a tendency for stimulus, similar to the conditioned stimulus, to elicit a response similar to the conditioned response. And the idea to take away from this is usually the more similar the new stimulus is to the original conditioned stimulus, the greater the conditioned response will be. So the sound of my desk drawer opening and the sound of my refrigerator door opening sound similar enough to elicit the response to my guinea pig behaving excitedly, the same way she behaves about carrots. So we call that generalization. And generalization has an adaptive value to it because it allows us, whether we're talking about humans or other animals, to make an appropriate response to similar stimuli. For instance, you may know exactly what your best friend's smile looks like. And their smile probably elicits feelings of joy in you. However, when it comes to meeting someone new for the first time, if you see them smile at you, it will probably also elicit feelings of joy. So that's the idea behind generalization. Now, I don't want you to think everything is broken or stuck in my apartment. My dresser drawer actually opens just fine. It makes a sound. But it's more a rumbling sound than a popping sound. And when I open my dresser drawer, my guinea pig does not respond to the sound by behaving excitedly. And the term for this is discrimination. And discrimination is when a human or any other type of animal learns to make a particular response to some stimuli, but not to others. Discrimination also has adaptive value because it's important to respond differently to related stimuli. You wouldn't want to respond to all loud sounds in exactly the same way. I mean think about it. Wouldn't you respond differently to the loud bang of a drum versus a loud bang of a gunshot? I know I would. Now, we've talked about how my guinea pig behaves excited about the sound of the refrigerator door opening, even when I'm opening it to make a snack for myself, with no intention to give her a carrot. And I know this because it's happened a few times. And if she doesn't receive a carrot for a few instances every so often, that's no big deal. The classical conditioning can endure. And she continues to respond to sound of the door by behaving excitedly. However, if I decided to stop giving her carrots altogether, eventually she would learn that the sound the refrigerator door alone isn't followed by a carrot. And the sound of the refrigerator door would gradually stop making her behave the same way she behaves when she receives a carrot. And we refer to this phenomenon as extinction. And it's when the conditioned stimulus is repeatedly presented without the unconditioned stimulus. And so, eventually, the conditioned stimulus is no longer able to elicit the conditioned response. But don't think of extinction as something that bad unless you're an endangered species. The process of extinction is used in therapy to treat phobias. For instance if you were afraid of heights, a therapist might use the concept of extinction by exposing you to various heights and eventually the stimulus of heights would no longer elicit the same response of fear. Finally, let's say my guinea pig now no longer responds to the sound of my refrigerator door opening. But suddenly, out of the blue one day, she hears the refrigerator door opening and spontaneously responds with some level of excitement. The spontaneous occurrence of the previously conditioned response is what's known as spontaneous recovery. And no one really knows why this happens. Generally when spontaneous recovery of a conditioned response occurs, it doesn't persist for very long. And it usually isn't quite as strong as it used to be. So maybe instead of behaving extremely excited to the sound of the refrigerator door, she just seems kind of intrigued, at least more than usual. So that's spontaneous recovery. So now you know the four common phenomena associated with classical conditioning-- generalization, discrimination, extinction, and spontaneous recovery.