Classical Conditioning(CC) is where a person or animal learns to associate two stimuli in terms that one stimulus comes to elicit a response that was “originally was elicited by the other stimulus” (Passer, Psychology, The Science of Mind and Behaviour, 6th edition, Mcgraw Hill).
Before I start to describe the roles in which classical conditioning might play in Human Behaviour key terms must be defined. An Unconditioned Stimulus (UCS) is where the stimulus has a biological relevance to the animal/human. There is no stimulus/response with it as it is already natural to the animal. An Unconditioned Response (UCR) are inbuilt reflexes.
A Conditioned Stimulus (CS) is something that proceeds an unconditioned Stimulus by a short interval as to create an association for a stimulus/response.
A Conditioned Response (CR) is like an unconditioned response but is not as strong and can happen in the absence of UCS.
One of the roles that CC plays in Human Behaviour is in treating phobias. One of the ways to get someone over their fears is to do it by a stimulus hierarchy. This is where a person starts small in the sense of getting over their phobia, one example of this is to be in the same room as a spider, and then they work up by getting closer and closer to the spider.
Here the response of fear is being extinguished as it lets a person go as far as they want but at the same time they are still counteracting their phobia by learning to disassociate their phobia with the feeling of fear.
Systematic desensitisation is where a person is made to relax their muscles before being subjected to the stimulus(phobia) and this means that their anxiety levels will not be as high and this will then help with the disassociation with the phobia.