Nervous System [6]: Conditioning (A Level Biology)


Uploaded by freeeschool on 02.09.2012

Transcript:
A Level Biology_Nervous System 6-Conditioning
Welcome to my sixth video in this series on the nervous system and this one has to do
with conditioning. As a quick introduction to conditioning, if
you take a look at the following clips. Usually, we’ll probably recognize what those symbols
are and this is a form of conditioning. So, we’re probably aware of what this brand
is. This is the brand Mercedez. You will probably because you’ve been exposed to a number
of times. You all realize that this symbol means the car brand Mercedez, but if you were
to show to someone who had no exposure to advertising or any form of influence like
that, they wouldn’t have any concept of this representing a car chain; the two things
wouldn’t seem to be linked. What this shows is this is learned behavior. You’ve learned
that this symbol means Mercedez much in the same way that you’ve learned that this symbol
means Pepsi, this one means HSBC, this one means McDonalds, and this one means Apple.
Probably the most famous example of conditioning has to do with the guy called Pavlov and he
did a lot of work modeling conditioning in dogs. This dog on here shows the methodology
that he used. The first thing that he did was he presented the dog with the food. Obviously,
the dog began to salivate. So, we can think of the food as our primarily stimulus. It’s
the thing that was shown to the dog and that caused the response, and the response, in
this case, is salivation. So, this diagram here shows us what happens
before the dog had become conditioned. Now, the bell here is what’s known as the secondary
stimulus. The bell being rang just on its own caused no response in the dog as you would
expect because the dog haven’t learn that the bell is associated with the food yet.
This shows what happens before the conditioning. Now, this next thing that he did was he put
the bell with the food. So, every time the food was put down, Pavlov or one of the people
working on the experiment rang the bell as well, and what happened was that the dog would
salivate, and the dog would salivate because of the presence of the food.
Now, he repeated this over and over again. So, every time he put the food down, he rang
the bell and he repeated this a number of times until the dog began to associate the
food with the bell. Now, the final piece of the jigsaw is when he didn’t put down the
food and just rang the bell. Now, what happened at this point, because the dog associated
the bell with the food, the dog began to salivate and that’s what’s referred to as a conditioned
response. The dog had learned that the bell usually came along with the food and, hence,
salivation. So, just to summarize there then, you have
the primary stimulus which is the food; you have the secondary stimulus which the bell,
and you have the response which is salivation. So, in a conditioned response, what’s technically
happening is the secondary stimulus or the bell causes the response, which is salivation,
even though the two are not directly linked. There’s no reason, there’s no reason why
the bell should caused salivation in the dog. It’s the fact that the dog has learned that
the bell is associated with the primary stimulus which is the food, and hence, you get a conditioned
response; the dog salivates when you ring the bell.
Most of our responses, as humans too, on different stimuli are usually conditioned. Another reasonable
example of this is when the bell rings at the end of a lesson. That’s a conditioned
response you’ve learned that at the end of the lesson or the bell usually means the
end of the lesson. Now, if you rang the bell and simply have no experience of school, then
they wouldn’t realize that that bell meant the end of the lesson, and hence, that’s
a conditioned response. In summary, conditioning is a learned response.
Probably the best example of conditioning has to do with Pavlov’s dogs. This is where
Pavlov linked or rang a bell and placed food down in front dog simultaneously. He repeated
this process a number of times. He then, on one occasion, removed the food and only rang
the bell. The dogs then associated the bell with the food and, hence, this caused salivation.
In this example, the food is the primary stimulus, the secondary stimulus is the bell, and the
response is salivation. Technically, what conditioning is, is where a secondary stimulus
causes a response even though that the two are not directly linked. Most responses in
humans are conditioned or learned responses.