Operant Conditioning Thomas G. Bowers, Ph.D. Penn State Harrisburg

Operant Conditioning n Thought to operate upon the environment n So-called “voluntary behavior” n Thorndike aimed to explain goal directed behavior –Developed Law of Effect

Law of Effect n Behavior is sensitive to its consequences n Positive reinforcement - Pleasurable consequences stamp in the behavior n Punishment - Unpleasant events stamp out the behavior

Behavior-consequence Relationship n Positive reinforcement acts to increase the probability of behavior n Punishment acts to decrease the probability of behavior

Behavior-consequence Relationship n Negative reinforcement (or escape) acts to increase behavior which eliminates or removes the negative stimulus n Omission removal of a positive stimulus decreases behavior

Response-consequence Relationships Response Stimulus

Conditioning and Extinction n Responses are developed by a shaping process of successive approximations n Extinction refers to the cessation of reinforcement

Behavioral Units Time Response/Min Acquisition Extinction

Contingency Learning P(Sr/No Res) P(Sr/R)

Operant Contingency Space n Reinforcement has a contingent effect, increasing behavior, while punishment or even non-reinforcement will decrease behavior n When reinforcement and responses are independent, or noncontingent, then learned helplessness results

Operant Contingency Space n Learned helplessness resembles depression n Seligman developed the paradigm n Leads to a global failure to initiate behavior n Associated with depletion of monoamine neurotransmitters

Operant Conditioning n What is learned? n R - S relationship? n How can something temporally remote (i.e. following) cause an event? n Some theorists emphasize S - R relationships

Avoidance Behavior n Much of our day to day behavior may serve to avoid negative or aversive stimuli or consequences n Signaled avoidance trials –Early training does not avoidance, but escapes the stimulus –Latency tends to decrease

Avoidance Behavior n Shock postponement procedure –Also called free-operant avoidance –Sidman avoidance n Most animals manage to learn this well, with few actual shocks experienced

Theories of Avoidance n Does the animal “know”?

Theories of Avoidance n Two factor theory - Mowrer –Initial learning by reinforcement of escape behavior –Classical conditioning also occurring, and CS acquires fear eliciting properties –Response here is reinforced by fear (CS) removal –Avoidance behavior results

Theories of Avoidance n Tests to inhibitory procedures appear to confirm predictions n Some problems, though –animals will respond reliably even if only a reduction of shock frequency is the contingency –there is little evidence of conditioned fear in well-trained animals

Theories of Avoidance n Some problems, though –avoidance of extinction –avoidance can be extinguished, but by response blocking

Cognitive Theories n Expectancy theory –Organism prefers no shock to shock –Organism expects if it responds, no shock will occur –Organism expects if it does not respond, shock will occur –Expectancies are strengthened when confirmed, weakened when disconfirmed

Cognitive Theories n Expectancy theory –Probability of avoidance increases as the degree of confirmation increases

Biological Theories n Bolles emphasized the adaptive significance to persistent avoidance learning n Described a repertoire of defensive reactions n Species-specific defensive reactions (SSDR)

Biological Theories n Hierarchical organization n Some patterns of responses are much easier to acquire than others

Conditioned Reinforcement n Neutral stimuli can also become a conditioned reinforcer n Predictiveness, informativeness is important to becoming a secondary reinforcer n Animals will respond for the opportunity to gain informative stimulus conditions

Applications of Secondary Reinforcement n Token economies –Common in our environment –Generalized secondary reinforcers –Functions n Provide feedback n Provide information about what to do next n Serve to bridge long gaps in reinforcement –Economies now build in inflation