Theoretical Analysis of Classical Conditioning

Thomas G. Bowers, Ph.D.

Penn State Harrisburg

Adaptive Function of CR

What adaptive contributions have been made by an organisms ability to demonstrate classical conditioning?

Organisms not only learn CS-UCS relationships, they appear to be adaptive for the organism

The relationships are often of biological significance

CR That Oppose UCR

Well trained animals demonstrate an antagonistic CR to some aversive stimulation

Examples include the conditioned development of tolerance

Tolerance is a biological adaptation, the adjustment of the body to maintain homeostatic tone

CR That Oppose UCS

For example, biological adjustment to regular doses of most drugs or medications

Adaptation to the use of alcohol or morphine, or any other psychoactive substance

More recently, we have now considered the role of classical conditioning in the development of tolerance

CR That Oppose UCS

Opponent process theory developed to explain patterns of conditioning

Solomon & Corbit, 1974 Hedonic or emotional stimulus also

produces a later effect opposite of the initial process

Referred to as process “a” or process “b”

CR That Oppose UCS

Opponent process theory developed to explain patterns of conditioning

“A” process develops early, but “B” processes begin to occur earlier over time

These processes summate to attenuate the overall response

Opponent Process Theory

a

b

Early trials

a

b

Later trials

Opponent Process Theory

Early trials

Later trials

Habituation

Reduction of responding after many stimulation trials

Can be understood by opponent process models

What Is Learned in Conditioning?

CS

UCS UCR

S-R Learning

CR

UCS UCR

S-S Learning

Some Processes

Sensory Preconditioning Phase One

CS2 Buzzer

CS1 Light

CS1 Light

UCS Food

Sensory Preconditioning Phase Two

Some Processes

Test to CS 2 Yields CR

CS2 Buzzer

These results indicate CR occurs to CS2, implying S-S learning

Some Processes

Second Order Conditioning

CS1Light

UCSFood

CS1

CS2Buzzer

Some Processes

Test to CS 2 Buzzer

Conditioning occurs here, and may seem to be due to S-R learning, but S-S explanations are also possible

CS2

Explanations of Classical Conditioning Mere CS-UCS pairing is not enough There is also required to be a contingency Example of the informative nature of

weather reports

Significance of Contingency

Fear and anxiety results from aversive circumstances

Anxiety is more reflective on non-contingent or difficult to predict circumstances

Fear may be more stimulus bound

Conditioning Can Be Selective

Kamin demonstrated blocking effects of one of a set of compound stimuli

One stimulus provides redundant information

Conditioned inhibition can develop if the second stimulus signals safety

Rescorla Wagner Theory

Describes negatively accelerated learning curve

Vn = K( - V n-1) Where V is associative strength, is the

change in response strength, is the asymptote of conditioning. K reflects salience of the CS-UCS

Rescorla - Wagner Theory

V1

V2

V3

Rescorla - Wagner Theory

Theory predicts redundant stimuli become inhibitory, which is also demonstrated experimentally

On the other hand, the theory does not explain latent inhibition well

This develops to pre-exposure to the CS Now thought of as learned irrelevance

Rescorla - Wagner Theory

Accounted for by K in theory Psychological significance has been the

source of debate