Conditioning and Learning Exam 3 Instrumental Learning What is Reinforcement Nature of reinforcement what makes something reinforcing how can we explain individual differences in what we find reinforcing 1 Reinforcement Thorndike stimulus that produces satisfying state of affairs Stimulus that strengthens instrumental behavior But why does it strengthen instrumental behavior 2 Historic Drive Reduction Theory Clark Hull all organisms have basic drives Ex Food water shelter Idea Primary reinforcers satisfy those drives Problem secondary reinforcers do not lead to primary reinforcers cannot explain many strong reinforcers EX money can t have enough of it primary reinforcers like music or art EX rats and their toys 3 Contemporary view theories focused on how or why reinforcement changes the organization of an animal s activities Redefine reinforcement not a stimulus it is a behavior Ex Food is not a reinforcer act of eating is a reinforcer because it is a behavior Theory same issues Species typical responses are reinforcing EX chewing licking swallowing A Consummatory Response Theory similar to Drive Reduction behaviors they reinforce Ex lever pressing Behaviors are special and different from instrumental B Primack Principle higher probability behaviors can reinforce lower probability behaviors Something you would prefer to do can reinforce something you would not prefer to do if given the choice between the two free access to pinball and candy ask if they eat more candy do they want to obtain access to pinball game or play pinball and want candy R candy eating or pinball playing O pinball Ex Pinball candy experiment 1965 observe children with playing or candy Results more pinball preferred kids eating candy to play pinball and candy preference kids played pinball to eat candy More preferred behavior reinforcer Key features any high probability behavior can reinforce only lower probability behavior Individual differences can be accounted for Must observe and determine what is high probability in each subject downside Hypothesis Disequilibrium Model restricting access to response makes it more reinforcing even a low probability behavior can be reinforcing if it is limited depriving you to make response Ex things on sale at store have limit people buy to limit Alternatives Response Deprivation Ex Timberlake Allison 1974 measured rats responses running on a wheel and licking spout for sucrose solution Free access to establish baseline Licking contingent on running 30 spins for 10 licks running contingent upon licking 60 licks for 5 spins Licking is the reinforcer then running is deprive them of responses they usually like to do Results more wheel turns and less licking more licking to run more By limiting access to licking raising wheel running despite personal preference By limiting running raised licking Thought Primack didn t restrict applied use ex worksheets classroom management ex schizophrenics psychiatric treatments C Behavioral Bliss point goes beyond Primack and Response Deprivation Hypothesis organism has optimal distribution of activities Instrumental contingencies force the individual out of optimal state Behavior changes to get back to bliss point or as close as possible Ex student likes watching TV doesnt like studying Bliss point 60 minutes TV for every 15 minutes studying Want to increase studying contingency is 1 minute of studying 1 minute of TV Compromise is 30 minutes of each Behavioral regulatory mechanisms minimize deviation from bliss point Summary redefine reinforcement BEHAVIOR Instrumental conditioning creating new distribution of behaviors Responses defined by contingency Shortcoming no explanation to how trade offs are determined Extinction away ways Repeated presentation of CS with no US or no reinforcement for a previously reinforced behavioral response Contrast with forgetting forgetting results from passage of time extinction is an active training process Exposure to CS alone or operant responses alone Does not occur simply due to time passing Features 1 creates frustration expectation of US reinforcer is not met 2 extinction bursts Ex pressing elevator button repeatedly 3 increased response variability making little changes to type of response right Ex rat uses only one paw instead of both Ex key in lock trying different 4 reduce CR meaning extinction is successful or operant responding Does not undo original training Original learning can still be observed after extinction through spontaneous recovery renewal and reinstatement 1 Spontaneous Recovery no US or reinforcement Trials acquisition extinction break extinction Contrast with extinction bursts spontaneous recovery happens after successful extinction training and time off Extinction bursts happen RIGHT AWAY Ex hungry rats learn CS food association then have 4 days of extinction Two groups 1 tests immediately after extinction 2 tested 8 days after Results Trials acquisition extinction G1 immediately lowered rates after extinction G2 days later higher testing after 2 Renewal Trials acquisition extinction in context A then context B like a new room Ex rats learn tone foot shock association in context A split into three groups G1 extinction in context A G2 extinction in context B G3 no extinction Tested again in context A Measure conditioned suppression suppression ratio CS responses divided by CS preCS Measure freezing suppression of bar pressing low amount of freezing is good If CS causes complete suppression 0 Results 5 ratio of not responding at all during extinction phase with tone without foot shock and continued pressing or they hear a tone freeze then stop pressing During the no extinction or testing phase G1 level at top G2 increasing G3 bottom Changing the environment brought back responding Lower number more suppression more responding 3 Reinstatement trials acquisition extinction US give sugar pellet for free brings responding CS testing extinction Could also be stress induced or with a light Ex rats learn to bar press for cocaine Extinction no cocaine Three groups G1 cocaine G2 morphine G3 nothing Tested bar pressing again Extinction then injection of other drug depending on groups then testing Results cocaine highest bar pressing then morphine then nothing Clinical relevance extinction of problem behaviors or responses like drug addiction fear or anxiety due to past abuse can return easily though Ex human drug addiction rehab is extinction Spontaneous recovery renewal reinstatement up