Pavlovian Conditioning Basic Principles Thomas G. Bowers, Ph.D. Penn State Harrisburg
Development of a Conditioned Reflex CS UCS UCR CS UCS UCR
Development of a Conditioned Reflex Onset of CR advances to the onset of the CS CR does not exactly mimic the UCR, but generally closely resembles the UCR
Conditioned Fear Responses If the UCS is a brief noxious stimuli (such as an electric shock) conditioned fear can result Includes increase in heart rate, respiration, tension, urination and so on Also called conditioned emotional response (CER) or conditioned suppression
Conditioned Fear Responses CER can suppress a well developed operant Suppression ratio Rate Csa _______________________ Rate CSa + Rate CSb
Autoshaping Automatic shaping of key pecking or similar behavior Key pecking is elicited after successive trials of lighting key just before food delivery
Autoshaping Similar to Breland & Breland’s difficulty with shaping Racoon behavior Also described as sign tracking
Taste Aversion Learning Research by Gracia and Koelling (1966) Posed a paradox in our understanding of behavior Animals appearing to optimally learn some relationships, but to not managed to learn to other stimulus relationships
Taste Aversion Learning
Why Is Learning Selective? There can be learning to non-optimal temporal contiguity Yet no effective learning to more optimal temporal relationships Sometimes described as an associative bias
Inhibition and Excitation Most conditioning we discuss is excitatory in nature Extinction was thought to develop an inhibition of the conditioned response rather than a simple erasure of the CS-UCS connection
Methods to Detect Inhibition Presentation of a novel stimulus during extinction of of CS-UCS relationship should result in a CR This process is described as disinhibition, and the response returns in a full blown fashion Summation Test
Methods to Detect Inhibition Compound stimuli where a stimulus predicted safety should be able to reduce conditioned fear Resistance to reinforcement test - Previous training to a neutral stimulus should develop inhibition, and hence take longer to acquire a CR
Conditions Producing Inhibition Extinction Inhibition and delay –In delay conditioning, the CR tends to occur only in the later part of the CS – Presenting a novel stimulus early in the CS will result in increased CR
Conditions Producing Inhibition Discrimination and Generalization Process of distinguishing between CS+ and CS-, where CS+ signals the UCS is coming while CS- predicts the UCS will not be available
Conditions Producing Inhibition % of CR Trials CS- CS+
Discrimination Gradient % of CR K Hz CS+
Inhibitory Gradient % of CR nm Light wavelength CS-
Conditioned Inhibition Backward conditioning –Recall that if UCS precedes the CS, then conditioning does not occur –However, the CS becomes a conditioned inhibitor
What Is Learned in Conditioned Inhibition? S-S associations? S-R associations? CS appear to be “occasion setters”