D E F : A F O R M O F L E A R N I N G I N W H I C H R E S P O N S E S C O M E T O B E C O N T R O L L E D B Y T H E I R C O N S E Q U E N C E S

OPERANT CONDITIONING

THORNDIKE’S LAW OF EFFECT

• Edward L. Thorndike • Studied

instrumental learning • This is the

foundation of operant conditioning• Cat studies

LAW OF EFFECT

• DEF: if a response in the presence of a stimulus leads to a satisfying effects, the association between the stimulus and the response is strengthened• The cornerstone of

B.F. Skinner’s theory

SKINNER’S DEMONSTRATION• Skinner showed that

organisms tend to repeat those responses that are followed by favorable consequences

• Reinforcement: occurs when an event following a response increases an organism’s tendency to make that response

TERMINOLOGY

• Operant chamber: “Skinner Box”, a small enclosure in which an animal can make a specific response that is recorded while the consequences of the response are systematically controlled• Used to control Reinforcement contingencies:

rules that determine whether response lead to the presentation of reinforcers

OPERANT CONDITIONING

• Key dependent variable is subject’s response rate over time• Cumulative recorder:

creates a graphic record of responding and reinforcement in a Skinner box as a function of time

BASIC PROCESSES OF OPERANT CONDITIONING

• Shaping: the reinforcement of closer and closer approximations of a desired response• Important in

acquisition• Necessary when an

organism does not emit the desired response

BASIC PROCESSES OF OPERANT CONDITIONING

• Extinction: weakening and disappearance of a response tendency b/c the response is no longer followed by a reinforcer

• Resistance to extinction: when an organism continues to make a response after delivery of the reinforcer for it has been terminated

DISCRIMINATIVE STIMULI

• DEF: cues that influence operant behavior by indicating the probable consequences of a response• Regulate operant

behavior

STIMULUS GENERALIZATION/DISCRIMINATION

• Generalization: Responding to a new stimulus as if it were the original• Stimulus

discrimination: decrease in response to a new stimulus that resembles the original

REINFORCEMENT

• Strengthening of a response tendency• Defined after the

fact, in terms of effect on behavior• Reinforcement is

subjective

DELAYED REINFORCEMENT

• Favorable outcomes are more likely to strengthen a response if the outcome follows immediately

CONDITIONED REINFORCEMENT• Primary reinforcers:

events that are inherently reinforcing b/c they satisfy biological needs• Secondary

(conditioned) reinforcers: events that acquire reinforcing qualities by being associated w/primary reinforcers

INTERMITTENT REINFORCEMENT: EFFECTS OF BASIC SCHEDULES

• Schedule of reinforcement: determines which occurrences of a specific response result in the presentation of a reinforcer

INTERMITTENT REINFORCEMENT

• Continuous reinforcement: occurs when every instance of a designated response is reinforced• Intermittent, partial, reinforcement: occurs when

a designated response is reinforced only some of the time• Intermittent makes a response more resistant to

extinction• There are 4 types of intermittent reinforcement…

FIXED-RATIO (FR) SCHEDULE

• Ratio schedules require the organism to make a response a certain amount of times to gain a reinforcer• FR Schedule: the

reinforcer is given after a fixed number of nonreinforced responses

VARIABLE-RATIO (VR) SCHEDULE

• The reinforcer is given after a variable number of nonreinforced responses

FIXED-INTERVAL (FI) SCHEDULE

• Interval schedules require a time period to pass btwn presentation of reinforcers• FI Schedule: the

reinforcer is given for the 1st response that occurs after a fixed time interval has elapsed

VARIABLE-INTERVAL (VI) SCHEDULE

• The reinforcer is given for the 1st response after a variable time interval has elapsed• Interval length

depends on a predetermined avg.

RATIO VS. INTERVAL

• Ratio schedules produce more rapid responding• Variable schedules tend to generate steadier

response rates and greater resistance to extinction

CONCURRENT SCHEDULES OF REINFORCEMENT

• Concurrent schedules of reinforcement: consist of 2 or more reinforcement schedules that operate simultaneously and independently, each for a different response

MATCHING LAW

• States that under concurrent schedules of reinforcement, organisms’ relative rate of responding to each alternative tends to match each alternative’s relative rate of reinforcement• Quality of reinforcement earned also effects

response rate• Assumes organisms are working to maximize

their overall reinforcement

MATCHING AND FORAGING

• Optimal foraging theory: food seeking behaviors of many animals maximize the nutrition gained in relation to the energy expended to locate, secure, and consume various foods

POSITIVE REINFORCEMENT

• Occurs when a response is strengthened b/c it is followed by the presentation of a rewarding stimulus

NEGATIVE REINFORCEMENT• Occurs when a

response is strengthened b/c it is followed by the removal of an aversive stimulus• Don’t be confused by

word negative• Many everyday

behaviors effected by negative reinforcement

ESCAPE LEARNING

• Def: an organism acquires a response that decreases or ends some aversive stimulation• Shuttle box

AVOIDANCE LEARNING

• DEF: an organism acquires a response that prevents some aversive stimulation from occurring• Avoidance learning

responses are very resistant to extinction

TWO-PROCESS THEORY OF AVOIDANCE

• Avoidance begins b/c classical conditioning creates a conditioned fear• Avoidance is maintained by operant conditioning• Avoidance response is strengthened through

negative reinforcement

PUNISHMENT: CONSEQUENCES THAT WEAKEN RESPONSES

• Punishment occurs when an event following a response weakens the tendency to make that response• NOT NEGATIVE REINFORCEMENT!!!

PUNISHMENT• Can have side effects:• General suppression of

behavioral activity• Trigger strong emotional

responses• Physical punishment

often leads to aggressive behavior

• More effective to reinforce desirable behavior than punish undesirable behavior