Post on 16-Jan-2016
Learning
Prof. Tom Alloway
Definition of Learning
Change in behavior Due to experience relevant to what is being learned Relatively durable
Conditioning Learning associations
Operant Conditioning
B.F. Skinner (1953) – principle of reinforcement Operant chamber Emission of response Reinforcement contingencies Cumulative recorder
Operant Chamber
Basic Processes in Operant Conditioning
Acquisition Shaping Extinction Stimulus Control Generalization Discrimination
Reinforcement: Consequences that Strengthen Responses
Delayed Reinforcement Longer delay, slower conditioning
Primary Reinforcers Satisfy biological needs
Secondary Reinforcers Conditioned reinforcement
Intermittent Reinforcement: Effects of Basic Schedules
Continuous reinforcement Intermittent (partial) reinforcement
Ratio schedules Fixed Variable
Interval schedules Fixed Variable
Concurrent Schedules of Reinforcementand the Study of Choice
Concurrent Schedules - Two responses reinforced on independent schedules. Concurrent VI-VI is the most studied.
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.
Optimal foraging theory - Animals behave in a way that maximizes rate of intake of nutrition in relation to energy expended.
RARB
=rA
rB
RARA + RB
=rA
rA + rB
Positive and Negative Reinforcement
Increasing a response: Positive reinforcement = response followed by rewarding
stimulus Negative reinforcement = response followed by removal of an
aversive stimulus Escape learning Avoidance learning
Decreasing a response: Punishment Problems with punishment
Classical conditioning
Pavlov’s Demonstration Terminology
Unconditioned Stimulus (UCS) Conditioned Stimulus (CS) Unconditioned Response (UCR) Conditioned Response (CR)
Classical Conditioning: Terminology Continued
Eliciting a response = drawing forth Trial = pairing of CS and UCS (CS generally precedes UCS) Acquisition = forming a new conditioned response Stimulus contiguity = occurring together in time and space
Processes in Classical Conditioning
Extinction Spontaneous Recovery Stimulus Generalization Stimulus Discrimination Higher-order conditioning Sensory Preconditioning
Conditioned Emotional Response (CER)(Fear Conditioning in the Lab)
CER is most commonly studied form of classical conditioning.
First, a rat is trained to bar press in an operant chamber. Then, the rat is trained onto a medium-sized variable-
ratio schedule to produce rapid, steady responding. Electric shock can be used a UCS that will temporarily
suppress bar pressing. A light or tone can be used as a CS that initially has no
effect on bar pressing rate. 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.
The suppression ratio is measure used to determine how much the CS suppresses bar pressing.
Suppression Ratio
Suppression ratio will be 0.5 if the CS has no effect on bar pressing rate.
A suppression ratio less than 0.5 indicates that the animal is responding more slowly during of the CS than in its absence.
(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.
Suppression Ratio =
A_______
A + B=
Response Rate During CS (A)___________________________________________________Response Rate During CS (A) + Response Rate Without CS (B)
Higher Order Conditioning
Sensory Preconditioning
Stage 1 - CS1 – CS2 (Light – Tone)
Stage 2 - CS2 – UCS (Tone – Shock)
Stage 3 - Test CS1
Shuttle-Box Avoidance Learning
(Classical and Operant Conditioning Combined)
New Directions in the Study of Conditioning
Biological Constraints on Conditioning Instinctive Drift Conditioned Taste Aversion Evolutionary Perspective
Cognitive Influences on Conditioning Signal relations Response-outcome relations
Conditioned Taste Aversion
Observational Learning: Basic Processes
Observational learning or vicarious conditioning Extending the reach of conditioning processes
Albert Bandura Example: Punishment and aggressive behavior