What is Learned? Classical and Instrumental Conditioning Compared Classical Instrumental • Reinforcement Not • Reinforcement Contingent on Behavior Contingent on Behavior • Behavior Elicited by US • Behavior Emitted by Organism • Voluntary Responses • Involuntary Response (“Spontaneous”) (Reflex) • Many Conditionable • Few Conditionable Behaviors Behaviors Avoidance Learning Solomon & Wynne (1953) • Dog Placed in One Side of Apparatus • Overhead Lights Deliver CS • Floor Grid Delivers US – After CS-US Interval • Vault Barrier – Escape After US Onset – Avoidance Before US Onset Two-Factor Theory of Avoidance Learning Mowrer (1947); critiqued by Seligman & Johnston (1973) • Light ==> Shock – Respond During Shock ==> Escape – Respond Prior to Shock ==> Avoidance • Classical Conditioning – Anticipatory Fear Conditioned to Light • Instrumental Conditioning – Reinforce Escape/Avoidance • Cessation of Shock US • Cessation of Light CS The Stimulus-Response Theory of Learning • Association between Stimulus and Response – Pavlov: CS = Bell; CR = Salivation – Thorndike: CS = Puzzle Box; CR = Paddle Press – Skinner: CS = (Illuminated) Key; CR = Keypeck • Reinforcement – Pavlov: US = Meat Powder – Thorndike: Reward = Escape – Skinner: Reinforcement = Food Pellet Assumptions of S-R Learning Theory • Association by Contiguity – Co-Occurrence in Space, Time • Arbitrariness (Equipotentiality) – Any Stimulus, Any Response • Empty Organism – Organism as “Black Box” Collecting Ss, Rs • Passive Organism – Metaphor of “Conditioning” Taste-Aversion Learning (Bait Shyness) Garcia & Koelling (1966) • Compound CS – “Bright, Noisy, Sweet” Water • US – Foot Shock (Immediate Pain) – X-Rays (Delayed Nausea) • Avoidance Test of Conditioning – Choose Water Source • Bright, Noisy Water • Sweet Water Taste-Aversion Learning Garcia & Koelling (1966) All Subjects CS1 Light CS2 CS3 Noise Taste Group 1 US1 Shock UR1 Group 2 US2 UR2 X-Ray Preference Test of Conditioned Fear (Avoidance of Water Source) Garcia & Koelling (1966) CR (Licks per Mnute) 350 300 250 CS 200 Sweet 150 Bright/Noisy 100 50 0 Shock X-Ray US Implications for S-R Learning Theory • Arbitrariness – Taste-Nausea, Sight/Sound-Shock • Empty Organism – Internal Structure Shaped by Evolution • Association by Contiguity – CS, CR Distant in Space, Time • Law of Exercise – One-Trial Taste-Aversion Learning Species-Specific Defense Reactions Bolles (1970) • Escape/Avoidance Learning in Pigeons – Easy: Flap Wings, Stretch necks – Impossible: Key Peck • Escape/Avoidance Learning in Rats – Easy: Jump Up, Run – Hard: Lever Press • Avoidance Learning Capitalizes on Species-Specific Repertoire of Defensive Reactions – Built In by Evolution The Preparedness Principle (Belongingness) Seligman (1970); Rozin & Kalat (1971) By Virtue of Its Evolutionary History, Each Species is Predisposed to Learn Certain Associations • Prepared • Unprepared • Contraprepared Constraints on Learning • Biological – Evolutionary History • Cognitive – Internal Representation of CS  CR