Presentation on theme: "Learning Prof. Tom Alloway. Definition of Learning l Change in behavior l Due to experience relevant to what is being learned l Relatively durable n Conditioning."— Presentation transcript:
Reinforcement: Consequences that Strengthen Responses l Delayed Reinforcement n Longer delay, slower conditioning l Primary Reinforcers n Satisfy biological needs l Secondary Reinforcers n Conditioned reinforcement
Intermittent Reinforcement: Effects of Basic Schedules l Continuous reinforcement n Intermittent (partial) reinforcement m Ratio schedules u Fixed u Variable m Interval schedules u Fixed u Variable
Concurrent Schedules of Reinforcement and the Study of Choice l Concurrent Schedules - Two responses reinforced on independent schedules. Concurrent VI-VI is the most studied. n Matching law The ratio of the response rates on two manipulanda is equal to the ratio of their reinforcement rates. The relative rate of responding on a manipulandum is equal to its relative rate of reinforcement. n Optimal foraging theory - Animals behave in a way that maximizes rate of intake of nutrition in relation to energy expended.
Positive and Negative Reinforcement l Increasing a response: n Positive reinforcement = response followed by rewarding stimulus n Negative reinforcement = response followed by removal of an aversive stimulus m Escape learning m Avoidance learning n Decreasing a response: m Punishment m Problems with punishment
Classical conditioning l Pavlov’s Demonstration n Terminology m Unconditioned Stimulus (UCS) m Conditioned Stimulus (CS) m Unconditioned Response (UCR) m Conditioned Response (CR)
Classical Conditioning: Terminology Continued l Eliciting a response = drawing forth l Trial = pairing of CS and UCS (CS generally precedes UCS) l Acquisition = forming a new conditioned response l Stimulus contiguity = occurring together in time and space
Conditioned Emotional Response (CER) (Fear Conditioning in the Lab) l CER is most commonly studied form of classical conditioning. l First, a rat is trained to bar press in an operant chamber. l Then, the rat is trained onto a medium-sized variable- ratio schedule to produce rapid, steady responding. l Electric shock can be used a UCS that will temporarily suppress bar pressing. l A light or tone can be used as a CS that initially has no effect on bar pressing rate. l If a CS precedes the shock several times, it acquires the capacity to suppress bar pressing. The CS’s acquired response suppression is a CR. l The suppression ratio is measure used to determine how much the CS suppresses bar pressing.
Suppression Ratio l Suppression ratio will be 0.5 if the CS has no effect on bar pressing rate. l A suppression ratio less than 0.5 indicates that the animal is responding more slowly during of the CS than in its absence. l (A suppression ratio greater than 0.5 would indicate that the animal is responding faster during the CS. That shouldn’t happen (except by chance) during CER conditioning.
Sensory Preconditioning l Stage 1 - CS 1 – CS 2 (Light – Tone) l Stage 2 - CS 2 – UCS (Tone – Shock) l Stage 3 - Test CS 1
Shuttle-Box Avoidance Learning (Classical and Operant Conditioning Combined)
New Directions in the Study of Conditioning l Biological Constraints on Conditioning n Instinctive Drift n Conditioned Taste Aversion n Evolutionary Perspective l Cognitive Influences on Conditioning n Signal relations n Response-outcome relations
Observational Learning: Basic Processes l Observational learning or vicarious conditioning n Extending the reach of conditioning processes l Albert Bandura n Example: Punishment and aggressive behavior