4.1 Learning Through Classical Conditioning

acquiring a new response (the CR) to a previously neutral stimulus (the CS) that reliably signals the arrival of an US

learning that one stimulus signals the arrival of another stimulus

any sight, sound, smell, taste, or body sensation that a human or animal can perceive

Pavlovian conditioning • because Pavlov was the first researcher to study this type of learning systematically

a stimulus-response pair in which the stimulus (the US) automatically elicits the response (the UR)

UCS, UCR, CS, and CR

a stimulus that does not naturally elicit the to-be-conditioned response

the response in a reflex that is automatically elicited by the unconditioned stimulus

the stimulus in a reflex that automatically elicits an unconditioned response

the stimulus that comes to elicit a new response (the conditioned response) in classical conditioning

the response that is elicited by the conditioned stimulus in classical conditioning

Pavlov began with a neutral stimulus (a tone) in his conditioning research on dogs. Before conditioning, his dogs did not automatically salivate to these stimuli. They had to learn (be conditioned) to do this. To achieve such conditioning, the neutral stimulus (for example, a tone) is presented just before the UCS (the food). Once the conditioning occurs (signaled in Pavlov's research by the dog salivating to the sound of the tone before the meat powder is put into its mouth), the neutral stimulus is referred to as the conditioned stimulus (CS).

This previously neutral stimulus (the tone) comes to elicit a new response (salivating) after repeated pairings with the unconditioned stimulus (meat powder in the dog's mouth). The learned response (salivating) to the conditioned stimulus (the tone) is called the conditioned response (CR). The conditioned response (salivating) is a preparatory response for the impending UCS (meat powder in the dog's mouth).

this can mean a few seconds, but the optimal time interval between the onsets of the two stimuli is usually very brief, only a half-second to a full second *because the conditioning involves learning that this stimulus is a reliable predictor for the arrival of the UCS*

the CS in these two cases would not be a good predictor of the UCS.

The *CS has to clearly predict the UCS by being presented first or conditioning usually will not occur*

taste aversion

• delayed conditioning • trace conditioning

a classical conditioning procedure in which the CS comes before the US and remains present until after the UCS is presented so that the two stimuli occur together. • the CS is "delayed" until after the UCS starts i.e. in Pavlov's experiment the tone is turned on and left on until the meat powder is put in the dog's mouth

a classical conditioning procedure in which the CS comes before the UCS but is removed before the UCS is presented so that the two stimuli do not occur together. classical conditioning procedure • there is a period of time between turning off the CS and the onset of the UCS (called the trace interval), when neither stimulus is present

In classical conditioning, you start with a reflex—an unconditioned stimulus (UCS) that automatically elicits an unconditioned response (UCR). To condition a new response to a neutral stimulus, the neutral stimulus is presented just before the unconditioned stimulus.

After several pairings, the neutral stimulus elicits a new response called the conditioned response (CR). The neutral stimulus is now referred to as the conditioned stimulus (CS).

To examine the possible role of such conditioning in human emotional responses such as fear As a neutral stimulus, the researchers used a white laboratory rat.

Albert was not afraid of the rat. In fact, when he saw the rat before the conditioning, he moved toward it and touched it. What was the reflex that Watson and Rayner used? While Albert was looking at the white rat, Watson quietly sneaked behind him with an iron bar and a hammer and clanged them together. Albert's reflexive response, the UCR, was the fear-avoidance response (crying and trying to crawl away) to this unexpected loud noise, the UCS. Watson and Rayner paired the sight of the white rat (the neutral stimulus that became the CS) with the unexpected loud noise (the UCS) several times until the sight of the white rat started eliciting the fear-avoidance response (crying and trying to crawl away from the rat).

He also generalized this conditioned fear response to a rabbit.

classical conditioning is used in advertising in order to condition positive attitudes and feelings toward products John Watson pioneered this type of advertising when he worked as a psychology consultant for the J. Walter Thompson advertising agency

- acquisition - extinction - spontaneous recovery - stimulus generalization - discrimination.

(in classical conditioning) acquiring a new response (the conditioned response) to the conditioned stimulus

(in classical conditioning) the diminishing of the conditioned response when the unconditioned stimulus no longer follows the conditioned stimulus

(in classical conditioning) a partial recovery in strength of the conditioned response following a break during extinction training and indicates that the CR may still be available in a weakened or inhibited form

Recovery Panel (a) depicts the acquisition of the CR.

Note that during acquisition, the UCS follows the CS on each trial. Acquisition of the CR is reflected in the increase in its strength across conditioning trials. Extinction is depicted in panel (b). On extinction trials, the UCS never follows the CS. This process is reflected in the decrease of the strength of the CR across extinction trials. Note, however, that when a break is taken during extinction training, there is a temporary partial recovery in strength of the CR following the break, depicted in panel (c).

This partial recovery is called spontaneous recovery. The amount of recovery lessens as extinction training continues.

stimuli similar to the CS elicit the CR. The more similar the stimulus is to the CS, the stronger the response will be • generalization is an adaptive process.

is the elicitation of the CR only by the CS or only by a small set of highly similar stimuli that includes the CS • in the dog bite example, this would be learning only to fear potentially dangerous dogs

because generalization is the broadening of the conditioned response to other stimuli, whereas discrimination is the narrowing of the response to only the stimulus followed by the UCS and those stimuli so similar to this stimulus that they cannot be discriminated from it

These are idealized stimulus generalization and discrimination results following classical conditioning of the salivary response (CR) in dogs to a tone of 1,000 Hz (CS). The strength of the CR to generalization test stimuli (all tones except the 1,000 Hz tone) decreases as the similarity of the test stimulus to the original CS decreases.

These generalization responses, however, can be extinguished through discrimination training in which the UCS (food) only follows the 1,000 Hz tone. The CR to each of the other tones will be extinguished except for the tones so similar to the 1,000 Hz tone (975 Hz and 1,025 Hz) that the dog does not perceive them as different.

The generalization stimuli did not vary symmetrically around the white rat, but the same pattern of generalization results were observed. As the generalization test stimuli became less similar to the CS (the white rat), the strength of the CR (the fear-avoidance response) decreased. The response to the other animals and the coat was stronger than the responses to the mask and hair.

Similarly, the response to the white cotton was even less, and it was nonexistent for the toy blocks.

What do you think happens? What normally happens to the CR when the UCS is removed in classical conditioning? It is extinguished. This is what *discrimination training* does; it diminishes the responding to the other stimuli.

The Little Albert study is an example of using the delayed classical conditioning procedure because the CS (the white rat) was presented before the UCS (the loud, unexpected noise) and remained there until the UCS was presented. If the white rat had been taken away before the unexpected loud noise, then the study would have been an example of using the trace conditioning procedure.

*Extinction* because the responses to all stimuli except the original CS are diminished because the UCS does not follow any of them. However, if a stimulus cannot be discriminated from the CS, the response to it is not extinguished.