Theoretical Analysis of Classical Conditioning Thomas G. Bowers, Ph.D. Penn State Harrisburg

Adaptive Function of CR w What adaptive contributions have been made by an organisms ability to demonstrate classical conditioning? w Organisms not only learn CS-UCS relationships, they appear to be adaptive for the organism w The relationships are often of biological significance

CR That Oppose UCR w Well trained animals demonstrate an antagonistic CR to some aversive stimulation w Examples include the conditioned development of tolerance w Tolerance is a biological adaptation, the adjustment of the body to maintain homeostatic tone

CR That Oppose UCS w For example, biological adjustment to regular doses of most drugs or medications w Adaptation to the use of alcohol or morphine, or any other psychoactive substance w More recently, we have now considered the role of classical conditioning in the development of tolerance

CR That Oppose UCS w Opponent process theory developed to explain patterns of conditioning w Solomon & Corbit, 1974 w Hedonic or emotional stimulus also produces a later effect opposite of the initial process w Referred to as process “a” or process “b”

CR That Oppose UCS w Opponent process theory developed to explain patterns of conditioning w “A” process develops early, but “B” processes begin to occur earlier over time w 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 w Reduction of responding after many stimulation trials w 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 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 CS1 Light UCS Food CS1 CS2 Buzzer

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 w Mere CS-UCS pairing is not enough w There is also required to be a contingency w Example of the informative nature of weather reports

Significance of Contingency w Fear and anxiety results from aversive circumstances w Anxiety is more reflective on non- contingent or difficult to predict circumstances w Fear may be more stimulus bound

Conditioning Can Be Selective w Kamin demonstrated blocking effects of one of a set of compound stimuli w One stimulus provides redundant information w Conditioned inhibition can develop if the second stimulus signals safety

Rescorla Wagner Theory w Describes negatively accelerated learning curve w  V n = K(  - V n-1) w 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 w Theory predicts redundant stimuli become inhibitory, which is also demonstrated experimentally w On the other hand, the theory does not explain latent inhibition well w This develops to pre-exposure to the CS w Now thought of as learned irrelevance

Rescorla - Wagner Theory w Accounted for by K in theory w Psychological significance has been the source of debate