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