Extinction- lack of reinforcement of the response and the resulting decline in response rate -an operantly conditioned response declines in rate and eventually disappears if it no longer results in a reinforcer ex: rats quit pressing levers if food pellets no longer appear Extinction is not true “unlearning” of the response but rather a learned inhibition of responding The mere passage of time following extinction can partially renew the conditioned reflex; called spontaneous recovery Generalization- phenomenon in which , after conditioning, stimuli that resemble the conditioned stimulus will elicit the conditioned response even though they themselves were never paired with the unconditioned response. Discrimination training can abolish generalization between two stimuli. By not linking the unconditioned stimulus to the neutral stimulus that has been generalized to, the animal will discriminate.
Thorndike put cats into puzzle boxes and made them find the solution to their quandary. Thorndike did not elicit a response as Pavlov had, he had to wait for the animal to emit the proper response, learn from it and do it again. The trial and error process through which the animals learned the way to trip the latch was what Thorndike called his law of effect. Responses that produce a satisfying effect in a particular situation become more likely to occur again in that situation, and responses that produce a discomforting effect become less likely to occur again in that situation. Instrumental responses - actions which function as tools to work some change in the environment; also called operant responses. Ex: flipping a switch to light a room; rats pushing a lever to receive food Operant conditioning- learning process by which the consequence of an operant response affects the likelihood that the response will occur in the future.
We are pulled as well as pushed by events in our environment. We do not just react to stimuli; we also behave in ways to produce or obtain certain environmental changes or stimuli. Shaping- process in which successively closer approximations to the desired response are reinforced until the response finally occurs Consequences- what happens after a response positive reinforcement - the arrival of some stimulus following a response which makes the response more likely to occur; stimulus called a positive reinforcer negative reinforcement- the removal of some stimulus following a response which makes the response more likely to occur; stimulus called a negative reinforcer punishment- opposite of reinforcement; the consequence of a response decreases the likelihood that the response will occur
Neutral Stimulus—Bell• Does not normally elicit aresponse or reflex action byitself–a bell ringing–a color–a furry object
Unconditioned Stimulus—Food• Always elicits a reflex action:an unconditioned response–food–blast of air–noise
Unconditioned Response—Salivation• A response to anunconditioned stimulus—naturally occurring–Salivation at smell of food–Eye blinks at blast of air–Startle reaction in babies
Conditioned Stimulus—Bell• The stimulus that was originallyneutral becomes conditioned afterit has been paired with theunconditioned stimulus• Will eventually elicit theunconditioned response by itself
Conditioned Response• The original unconditionedresponse becomes conditionedafter it has been elicited by theneutral stimulus
Classical ConditioningPhenomenon• Extinction• Spontaneous recovery• Stimulus generalization• Discrimination training
John B. Watson and Little Albert• Conditionedemotionalresponses• Generalization• Extinction
Classical Conditioning and Drug Use• Regular use may produce “placeboresponse” where user associates sight,smell, taste with the drug effect• Conditioned compensatory response (CCR)—classically conditioned response in whichstimuli that reliably precede theadministration of a drug elicit physiologicalreaction that is opposite to the drug’s effects.May be one explanation for thecharacteristics of withdrawal and tolerance.
Cognitive Aspects ofClassical Conditioning• Reliable and unreliable signals• Actively process information• Robert Rescorla
Evolutionary Perspective• Conditioned taste aversions• Internal stimuli—associate better with taste• External stimuli—associate better with pain• Biological preparedness• John Garcia—not all neutral stimuli canbecome conditioned stimuli.
Early Operant Conditioning• E. L. Thorndike (1898)• Puzzle boxes and catsScratch at barsPush at ceilingDig at floorSituation:stimuliinside ofpuzzle boxHowlEtc.Etc.Press leverFirst Trialin BoxScratch at barsPush at ceilingDig at floorSituation:stimuliinside ofpuzzle boxHowlEtc.Etc.Press leverAfter ManyTrials in Box
B. F. Skinner’sOperant Conditioning• Did not like Thorndike’s term“satisfying state of affairs”• Interested in emitted behaviors• Operant—voluntary responsethat acts on the environment toproduce consequences
Reinforcement—the occurrenceof a stimulus following aresponse that increases thelikelihood of the response beingrepeatedOperant Conditioning
Reinforcers• Primary—a stimulus that is inherentlyreinforcing for a species (biologicalnecessities)• Conditioned—a stimulus that has acquiredreinforcing value by being associated witha primary reinforcer
PunishmentPresentation of a stimulus followinga behavior that acts to decreasethe likelihood that the behavior willbe repeated
Problems with Punishment• Does not teach or promotealternative, acceptable behavior• May produce undesirable resultssuch as hostility, passivity, fear• Likely to be temporary• May model aggression
Discriminative StimuliEnvironmental cues that tell us when a particular response islikely to be reinforced
Reinforcement Schedules• Continuous—every correct responseis reinforced; good way to get a low-frequency behavior to occur• Partial—only some correct responsesare reinforced; good way to make abehavior resistant to extinction
Partial Schedules—Ratio• Ratio schedules are based onnumber of responses emitted• Fixed ratio (FR)—a reinforcer isdelivered after a certain (fixed)number of correct responses• Variable ratio (VR)—a reinforcer isdelivered after an average number ofresponses, but varies from trial to trial
Partial Schedules—Interval• Interval schedules are based on time.• Fixed interval (FI)—reinforcer is deliveredfor the first response after a fixed period oftime has elapsed• Variable interval (VI)—reinforcer isdelivered for the first response after anaverage time has elapsed, differs betweentrials
Cognitive Aspects ofOperant Conditioning• Cognitive map—term for a mentalrepresentation of the layout of a familiarenvironment• Latent learning—learning that occurs inthe absence of reinforcement, but is notdemonstrated until a reinforcer is available• Learned helplessness—phenomenon inwhich exposure to inescapable anduncontrollable aversive events producespassive behavior
Biological Predispositions• Animal training issues• Instinctive drift—naturally occurringbehaviors that interfere with operantresponses