Psychology

Classical conditioning, or Pavlovian conditioning, was developed by Ivan Pavlov, a Russian physiologist. Classical conditioning is one of two kinds of associative learning, the other being operant conditioning, where associative learning is how the mind relates two events with one another. Ivan Pavlov designed an experiment where he would be able to elicit a response with a stimulus through repetitive association of that stimulus to one that normally or automatically elicits the desired response.
For Pavlovs particular experiment, he made use of dogs, food and a bell. He would ring a bell, show the dogs food and measure their salivation. During the early stages of the experiment, salivation would not be present until the dogs would see the food. As the experiment progressed, they began to associate the sound of the bell with the presentation of food and would salivate upon hearing the ringing. To the dogs, the sound of the bell meant food was on its way.

Now, we can define the roles of the elements of the experiment. In the experiment we have two important components  the food and the bell. First, the food for this experiment is what would be called the unconditioned stimulus, meaning its effect is automatic, basic or fundamental and the dog did not have to learn to salivate upon food presentation.

Second, we have the bell, the conditioned stimuli which would be related to the unconditioned stimulus to give it the ability to elicit the response that the unconditional stimulus draws out. Originally, this stimulus was neutral, meaning it doesnt elicit the response that the unconditioned response elicits, but due to the frequency of repetition of the association of events, it changed form and became the conditional stimulus.

From the previous point, we draw the conditioned response. The conditioned response arises from the connection between the previously neutral stimulus to the unconditional stimulus. It is this connection that would bring about the conditioned response even when the unconditioned stimulus is absent.
To integrate all the ideas together, an unconditioned stimulus is one that evokes the basic response that was not learned. Upon introduction of a neutral stimulus, there would be no effect upon its first presentation. As it is repetitively associated with the unconditioned stimulus, the subjects brain, in this case, the dogs brain would form a link between the two stimuli thus transforming the neutral stimulus to a conditioned one. The conditioned stimuli would bring about the response regardless of the presence of the unconditioned stimulus once the neutral stimulus is converted as a link is formed.

We could apply classical or Pavlovian conditioning as an explanation to the scenario of children expressing anxiety towards people in white coats resembling physicians or physicians in general. With this situation, we have the same elements  an unconditioned stimulus, a neutral stimulus, a response, a conditioned stimulus and a conditioned response.

During the first few visits to the doctor for a booster shot, a baby would pay no mind to the attending physician. When the shot is administered, the pain would naturally make the baby cry. When the baby is repeatedly exposed to the situation where he or she would receive a shot from someone in a white coat or a physician, he or she would link the physician to the idea of pain.

The situation mentioned would explain the phenomena of babies crying at the sight of a doctor or someone in a white coat. The unconditioned stimulus is the booster shot and it brings about the natural response of crying due to the pain from the said shot. In this case, the physician is the neutral stimulus early on but as the child is repeatedly hurt with the booster shot the child cannot help but form a link between forthcoming pain and the physician. This is the point wherein the physician is turned into a conditioned stimulus and crying at the sight of the physician would be a conditioned response.