Classical Conditioning: Underlying Processes and Practical Applications Chapter 5 Dr. Steven I. Dworkin Underlying Processes • • • • S-S versus S-R learning Stimulus Substitution versus Preparatory-Response Theory Compensatory-Response Model Rescorla-Wagner Theory Dr. Steven I. Dworkin S-S versus S-R Learning • S-R – Neutral stimulus becomes associated with unconditioned response. • S-S – Neutral stimulus becomes directly associated with the unconditioned stimulus. Dr. Steven I. Dworkin Stimulus-Substitution versus Preparatory Response Theory • Stimulus-Substitution – CS acts as substitute for US • Preparatory-Response Theory – The CR prepares the organism for presentation of US • Compensatory-Response Theory – The CR counteracts the effects of the UR Dr. Steven I. Dworkin Rescorla-Wagner Model of Conditioning • For every presentation of CS – Excitatory conditioning – Inhibitory conditioning – No conditioning Dr. Steven I. Dworkin Rescorla-Wagner Model of Conditioning • Behavioral theory of conditioning does not make inferences about expectations or other underlying cognitive functions • CS acquires a limited amount of associative strength on each trial. – Associative strength – magnitude of elicited CR – Maximum associative strength – Asymptote of maximum CR <=UR Dr. Steven I. Dworkin Rescorla-Wagner Model of Conditioning • CS gains certain amount of associative strength on any one trial. • Change is associative strength – difference between present strength of CS and maximum possible value. • This difference diminishes with each pairing as associative strength is increased. • The sum of the associative strength of all CSs <=UR Dr. Steven I. Dworkin Acquisition VMAX Associative Strength 10 8 Si=0.25 VMAX=10.00 VSUM= 0.00 6 4 2 0 0 2 4 6 Trials Dr. Steven I. Dworkin 8 10 Conditioning Effects and the RescorlaWagner Equation rVi = Si(VMAX–Vi-VSUM) rVi – amount of change in associative strength for any CS on any one trial. – Si – constant varies between 0.00 and 1.00 measure of salience of CS and sensory capacity of organism. Estimated after conditioning. How quickly associative strength raises to maximum. – VMAX – maximum associative strength – magnitude of UR – Vi – associative strength already accrued to CS1 – VSUM – associative strength already accrued to CS2…CSn Dr. Steven I. Dworkin Rescorla-Wagner Equation • • • • • • • • • • • • Trial 0. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10 T Assoc Strength .0000 2.5000 4.3750 5.7800 6.8550 7.6400 8.2300 8.6700 9.0000 9.2500 9.4400 • • • rVi = Si(VMAX–Vi-VSUM) Si=0.25 Vmax=10 Vsum=0 • • • • • i=1rVi =.25(10)=2.5 i=2rVi =.25(10-2.5)=1.88 i=3rVi =.25(10-4.375)=1.4 i=4rVi =.25(10-5.78)=1.05 i=5rVi =.25(10-6.85)=.78 Dr. Steven I. Dworkin Acquisition VMAX Associative Strength 10 8 Si=0.25 VMAX=10.00 VSUM= 0.00 6 4 2 0 0 2 4 6 Trials Dr. Steven I. Dworkin 8 10 Practical Applications • • • • Understanding Phobias Treating Phobias Aversion Therapy Medical Applications Dr. Steven I. Dworkin Understanding Phobias • Overgeneralizations • Watson and Rayner • Additional Factors – Observational learning – Temperament – Preparedness – History of control – Incubation –strengthening by brief exposure to CS – US revaluation – Selective sensitization Dr. Steven I. Dworkin Treating Phobias • Systematic desensitization – Counter conditioning • Reciprocal inhibition – Training in relaxation – Creation of hierarchy – Pairing of items in hierarchy with relaxation Dr. Steven I. Dworkin Treating Phobias • Flooding – prolong exposure to feared stimulus • Aversion Therapy Dr. Steven I. Dworkin Medical Applications • Neuropsychoimmunology • Drug Relapse Prevention Dr. Steven I. Dworkin Biological Preparedness • Equipotentiality premise – all environmental stimuli that can be detected by an organism can serve as conditioned stimulus. • A given stimulus will be equally good in all contexts Dr. Steven I. Dworkin Garcia and Koelling 1966 • • • • CS1 - bright noisy water CS2 – taste US1- illness US2- shock Dr. Steven I. Dworkin