Okay, so our conditioned responses aren't always permanent; they can actually go away, and we call that process extinction. Extinction is essentially the elimination of a learned response, and it's going to occur when the conditioned stimulus is repeatedly presented without the unconditioned stimulus. So, basically what's going to happen is after a few repetitions of no longer pairing these two things, the conditioned stimulus will no longer create the conditioned response. To kind of walk you through an example, let's just say we have our acquisition trials where our neutral stimulus, our bell, is getting paired with an unconditioned stimulus or some food. And, of course, over time we have learning taking place, we're getting more and more drops of saliva from that animal until eventually that bell by itself is going to be producing our response.
So, that bell is now a conditioned stimulus; it's producing a conditioned response, learning has taken place. Now, what's going to happen is during our extinction trials, we're going to present that conditioned stimulus alone. So we're going to ring the bell, but we're never going to give the dog any food. What's going to happen is for the first couple of trials, you're still going to see the conditioned response because the animal did learn it, right? So it's still going to be responding in some way. But, basically, over time as you repeatedly don't pair those two things anymore, eventually, that response will just disappear, and you can ring that bell and the animal is going to have no response to it at all.
Basically, what happened here, remember, we had taught the animal that the presence of this stimulus predicts the presence of this stimulus. Right? But when that association no longer holds true, then suddenly this bell essentially becomes neutral again. It completely loses meaning. It no longer predicts the presence of food, so the animal has no reason to respond to it.
Now, the speed at which extinction takes place can be affected by a few different things. So, the first is the duration and the frequency of the original conditioning. For example, if you have a conditioned response that was established over a week versus, you know, months of repeated trials, it's probably going to take longer to extinguish the one that you had established over months. Right? So just kind of the general duration and frequency of that original acquisition phase in the original conditioning can affect how long it will take for extinction to take place.
One other thing that can affect extinction is biological preparedness, which is a phenomenon that we see in organisms, both humans and animals, where we seem to make certain associations much quicker based on our evolutionary history or past. For example, it's much harder to extinguish conditioned fear responses. You know, it's obviously very evolutionarily advantageous to fear things. It keeps you alive. Right?
And so those responses can be harder to extinguish. The same goes for things like conditioned taste aversions. If you've ever had an aversion to a food after having a stomach bug, that can be really hard to make go away. Right? But there's obviously an evolutionary advantage to that.
If a food makes you sick, you want to avoid it. Right? And so things like biological preparedness can also affect the extinction process. Now, interestingly, extinction is not always necessarily permanent. We can see a phenomenon called spontaneous recovery.
So this is essentially going to be the reappearance of a conditioned response after apparent extinction, and it usually happens after a period of rest. So for example, if we look at our graph up here, what we might see is that, you know, after we have our extinction trials and our conditioned stimulus no longer creates that response, if we have a 48-hour rest period and then we bring our dog in and ring our bell, suddenly they're responding again. We have some salvation happening. So that would be an example of spontaneous recovery, and you can see it took a couple of trials, but then that response was extinguished again. And spontaneous recovery can actually happen multiple times for an animal, again, usually with brief rest periods in between each one.
Alright. So that is extinction, and I will see you guys in our next video. Bye-bye.