Because classical conditioning represents an extremely simple form of learning, it has been regarded by many psychologists as an appropriate starting point for the investigation of the learning process. We will now consider some of the laws that characterize classical conditioning.

Acquisition: Each paired presentation of the CS and the US is called a trial, and the period during which the organism is learning the association between the CS and the US is the acquisition stage of conditioning.

The time interval between the CS and the US may be varied. In simultaneous conditioning, the CS begins a fraction of a second or so before the onset of the US and continues along with it until the response occurs.

In delayed conditioning, the CS begins several seconds or more before the onset of the US and then continues with it until the response occurs. And in trace conditioning, the CS is presented first and then removed before the US starts (only a “neural trace” of the CS remains to be conditioned),

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In delayed and trace conditioning the investigator can look for the conditioned response on salivation occurs before the delivery of food, we consider it a conditioned response to the light.

In simultaneous conditioning the conditioned response does not have time to appear before the presentation of the US, and it is necessary to include test trials-trials on which the US is omitted- to determine whether conditioning has occurred.

For example, if salivation occurs when the CS is presented alone, we consider that conditioning has occurred. Delayed conditioning experiments indicate that learning is fastest if the CS is presented about 0.5 seconds before the US.

With repeated paired presentations of the CS and US, the conditioned response appears with increasingly greater strength and regularity. The procedure of pairing the CS and US is called reinforcement because any tendency for the CR to appear is facilitated by the presence of the US and the response to it. The left-hand panel of Fig. 4.5 shows the dog’s acquisition of the salivary response to the conditioned stimulus of a light.

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By the third trial the animal is responding to the CS with seven drops of saliva. By the seventh trial saliva secretion has leveled off and continues (with minor fluctuations) at about the same strength for the next nine trials. This stable level of responding is called the asymptote of the learning curve; further acquisition trails will not produce any greater strength of response.

Extinction:

If the unconditioned stimulus is omitted repeatedly (no reinforcement), the conditioned response gradually diminishes.

Generalization:

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It has been discussed in earlier under the section classical conditioning.

Discrimination:

It also has been discussed in earlier under the section classical conditioning.