Unit 6: Learning Learning Learning relatively permanent change in an organism s behavior due to experience experience (nurture) is the key to learning Different Types of Learning Classical -learn by association of stimuli Operant -learn through reinforcement or learning based on the association of consequences with one s behavior. Social Learning-learn by observing & imitating others. Cognitive Learning-learn through mental processes. Association We learn by association Our minds naturally connect events that occur in sequence Aristotle 2000 years ago John Locke and David Hume 200 yrs ago Associative Learning learning that two events occur together two stimuli a response and its consequences Association Event 1 Event 2 Sea snail associates splash with a tail shock Learning to associate two events Two related events: Stimulus 1 Lightning Stimulus 2 Result after repetition Thunder We learn to associate two stimuli Seal learns to expect a snack for its showy antics Stimulus We see lightning Response We wince anticipating thunder 1
Classical Operant Response Response: Pushing vending machine button Stimulus We learn to associate a response and its consequence Consequence:Receiving a candy bar Operant Ivan Pavlov 1849-1936 Russian physician/ neurophysiologist Nobel Prize in 1904 studied digestive secretions Pavlov s Experiments Classical organism comes to associate two stimuli lightning and thunder tone and food begins with a reflex a neutral stimulus is paired with a stimulus that evokes the reflex neutral stimulus eventually comes to evoke the reflex 2
Pavlov s device for recording salivation Unconditioned Stimulus (UCS) effective stimulus that unconditionallynaturally and automatically - triggers a response Unconditioned Response (UCR) unlearned, naturally occurring response to the unconditioned stimulus salivation when food is in the mouth Classical Conditioned Stimulus (CS) originally neutral stimulus that, after association with an unconditioned stimulus, comes to trigger a conditioned response Conditioned Response (CR) learned response to a previously neutral conditioned stimulus Acquisition the initial stage of learning, during which a response is established and gradually strengthened the phase associating a neutral stimulus with an unconditioned stimulus so that the neutral stimulus comes to evoke a conditioned response Extinction diminishing of a conditioned response in classical conditioning, when a unconditioned stimulus does not follow a conditioned stimulus 3
Strength of CR Acquisition (CS+UCS) Extinction (CS alone) Pause Spontaneous recovery of CR Extinction (CS alone) Spontaneous recovery reappearance, after a rest period, of an extinguished conditioned response Generalization tendency, once a response has been established, for stimuli similar to the conditioned stimulus to evoke similar responses Generalization Discrimination in classical conditioning, the ability to distinguish between a conditioned stimulus and other stimuli that do not signal an unconditioned stimulus Generalization Nausea among Cancer Patients Drops of saliva in 30 seconds 60 50 40 30 20 10 0 Hind paw Pelvis Shoulder Front paw Thigh Trunk Foreleg Part of body stimulated 4
Behaviorism John B. Watson viewed psychology as objective science generally agreed-upon consensus today recommended study of behavior without reference to unobservable mental processes not universally accepted by all schools of thought today Little Albert http://www.youtube.com/watch?v=9hbfnxa CsOI Little Albert s Fear UCS (loud noise) CS (rat) CS (rat) UCR (fear) UCS (loud noise) CR (fear) Stimulus similar to rat (such as rabbit) Conditioned fear (generalization) UCR (fear) Operant Operant type of learning in which behavior is strengthened if followed by reinforcement or diminished if followed by punishment Law of Effect Thorndike s principle that behaviors followed by favorable consequences become more likely Law of Effect Edward Thorndike s principle that behaviors followed by favorable consequences become more likely, and behaviors followed by unfavorable consequences become less likely. Thorndike believed that learning is governed by the law of effect. Instrumental learning -responses are strengthened when they are instrumental in producing rewards. Operant Operant Behavior complex or voluntary behaviors push button, perform complex task operates (acts) on environment produces consequences Respondent Behavior occurs as an automatic response to some stimulus 5
Operant B.F. Skinner (1904-1990) elaborated Thorndike s Law of Effect developed behavioral technology Operant Skinner Box soundproof chamber with a bar or key that an animal can manipulate to obtain a food or water reinforcer contains a device to record responses Operant Operant Reinforcer any event that strengthens the behavior it follows Shaping operant conditioning procedure in which reinforcers guide behavior toward closer approximations of a desired goal Principles of Primary Reinforcer an innate reinforcer satisfies a biological need Secondary Reinforcer a conditioned reinforcer an event that gains its reinforcing power through its association with a primary reinforcer Schedules of Continuous reinforcing the desired response each time it occurs learning occurs rapidly extinction occurs rapidly Partial reinforcing a response only part of the time results in slower acquisition greater resistance to extinction 6
Schedules of Fixed Ratio (FR) schedule that reinforces a response only after a specified number of responses the faster you respond, the more rewards you get different ratios very high rate of responding like piecework pay Schedules of Variable Ratio (VR) schedule that reinforces a response after an unpredictable number of responses like gambling, fishing very hard to extinguish because of unpredictability Schedules of Fixed Interval (FI) a schedule that reinforces a response only after a specified time has elapsed response occurs more frequently as the anticipated time for reward draws near Schedules of Variable Interval (VI) schedule that reinforces a response at unpredictable time intervals produces slow steady responding like pop quiz Schedules of Skinner s Experiments Schedules Number of responses 1000 750 500 250 Fixed Ratio Variable Ratio Rapid responding near time for reinforcement Fixed Interval Variable Interval 0 Steady responding 10 20 30 40 50 60 70 Time (minutes) 80 7
Punishment Punishment Punishment aversive event that decreases the behavior that it follows powerful controller of unwanted behavior Problems with Punishment Punished behavior is not forgotten, it's suppressed- behavior returns when punishment is no longer eminent Causes increased aggression- shows that aggression is a way to cope with problems- Explains why aggressive delinquents and abusive parents come from abusive homes Problems with Punishment Creates fear that can generalize to desirable behaviors, e.g. fear of school, learned helplessness, depression Does not necessarily guide toward desired behavior- reinforcement tells you what to do-- punishment tells you what not to do- Combination of punishment and reward can be more effective than punishment alone Punishment teaches how to avoid it Cognition and Operant Latent Learning Cognitive Map mental representation of the layout of one s environment example- after exploring a maze, rats act as if they have learned a cognitive map of it Latent Learning learning that occurs, but is not apparent until there is an incentive to demonstrate it 8
Cognition and Operant Cognition and Operant Overjustification Effect the effect of promising a reward for doing what one already likes to do the person may now see the reward, rather than intrinsic interest, as the motivation for performing the task Intrinsic Motivation Desire to perform a behavior for its own sake and to be effective Extrinsic Motivation Desire to perform a behavior due to promised rewards or threats of punishments Operant vs Classical Comparison of Classical and Operant Classical Operant Contrasting Classical and Operant The Response Involuntary, automatic Voluntary, operates on environment Acquisition Associating events; CS announces Associating response with a consequen- UCS. ce (reinforcer or punisher). Extinction CR decreases when CS is repeatedly Responding decreases when reinforcepresented alone. ment stops. Cognitive Subjects develop expectation that Subjects develop expectation that a processes CS signals the arrival of UCS response will be reinforced or punished; they also exhibit latent learning, without reinforcement. Biological Natural predispositions constrain Organisms best learn behavior similar to predispositions stimuli and responses can easily be their natural behaviors; unnatural beassociated. haviors instinctively drift back toward natural ones. Observational Learning Observational Learning learning by observing and imitating the behavior of others Modeling process of observing and imitating behavior Prosocial Behavior positive, constructive, helpful behavior opposite of antisocial behavior Observational Learning Mirror Neurons frontal lobe neurons that fire when performing certain actions or when observing another doing so may enable imitation, language learning, and empathy 9
Bandura s Experiments Bandura s Experiments Bandura s bobo doll experiment Applications of Observational Learning Prosocial vs Antisocial Effects Prosocial effects: positive, constructive, helpful behavior. The opposite of antisocial behavior. Antisocial effects Applications of Observational Learning Prosocial vs Antisocial Effects Biopsychosocial Influences on Learning 10