the gradual formation of an association between the conditioned stimulus and un-conditioned stimulus
this is Acquisition
The gradual formation of an association between the conditioned stimulus (CS) and unconditioned stimulus (UCS) is known as classical or Pavlovian conditioning. This type of learning involves pairing a neutral stimulus (CS) with a biologically significant stimulus (UCS) until the neutral stimulus can elicit a response (Conditioned Response or CR) that is similar to the response elicited by the biologically significant stimulus.
For example, consider the classic experiment conducted by Ivan Pavlov with dogs. Pavlov used a bell as the CS and meat powder as the UCS. Initially, the sound of the bell did not elicit any response from the dogs (neutral stimulus). However, after repeatedly ringing the bell just before feeding the dogs with meat powder, the sound of the bell became associated with the delivery of food. As a result, the dogs began to salivate in response to the bell (CR). Once the association between the CS (bell) and UCS (meat powder) was formed, the bell alone could elicit salivation in the dogs, even without the presentation of food.
The process of classical conditioning involves several stages including acquisition, extinction, spontaneous recovery, and generalization. During acquisition, the CS and UCS are repeatedly paired until the association between the two stimuli is firmly established. Extinction occurs when the CS is presented repeatedly without the UCS, resulting in the gradual disappearance of the CR. Spontaneous recovery refers to the reappearance of the CR after a period of rest or delay. Generalization occurs when the same CR occurs in response to similar but not identical stimuli.
Overall, the gradual formation of an association between the CS and UCS is an important aspect of classical conditioning, and this type of learning is widely observed in both humans and animals.