PSY 402Stimulus ControlDiscriminative StimuliTypes of ReinforcersBehavior ChainsSchedules of ReinforcementRatio SchedulesInterval SchedulesEffects of Schedule on BehaviorCompound SchedulesChoiceThe Law Works for Reward SizeA Law for One ChoiceImplications of the LawImpulsivenessHot and Cold ThoughtsBehavioral EconomicsTheories of ReinforcementProblems with Premack’s PrincipleBehavioral Regulation TheoryBlisspointSelection by ConsequencesPSY 402Theories of LearningChapter 7 – Behavior & Its ConsequencesInstrumental & Operant LearningStimulus ControlSkinner discovered that stimuli (cues) provide information about the opportunity for reinforcement (reward).The stimulus sets the occasion for the behavior.Fading – gradually transferring stimulus control from a simple stimulus to a more complex one.Operant behavior is controlled by both stimuli and reinforcers.Discriminative StimuliDiscriminative stimuli act as “occasion setters” (see Chap 5) in classical conditioning.The stimulus that signals the opportunity for responding and gaining a reward is SD.The stimulus that signals the absence of opportunity is S.Types of ReinforcersPrimary reinforcer – stimuli or events that reinforce because of their intrinsic properties:Food, water, sexSecondary reinforcer – stimuli or events that reinforce because of their association with a primary reinforcer:Money, praise, grades, sounds (clicks)Called conditioned reinforcers.Behavior ChainsSecondary (conditioned) reinforcers reward intermediate steps in a chain of behavior leading to a primary reinforcer.Secondary reinforcers can also be discriminative stimuli that set the occasion for more responding.Classical conditioning is a glue that enables chains of behavior leading to a goal.Schedules of ReinforcementBehavior is recorded continuously on a drum recorder.A cumulative graph shows the rate of responding over time.The steepness of the line indicates how quickly the rat is respondingHash marks indicate when reward was given.CRF (Continuous reinforcement) – the rat is rewarded every time it does the behavior.Ratio SchedulesFixed Ratio (FR) – there is a ratio between responding and reward.The rate is rewarded for every xth behavior.FR-15 means the rat gets one reward for every 15 behaviors (e.g., bar presses).Variable Ratio (VR) – the number of responses needed varies, but averages out to a particular ratio.VR-15 – the ratio varies but averages to 1:15.Interval SchedulesFixed Interval (FI) – rewards are given for the first response after a given amount of time has passed.FI-15 means one reward is given after 15 minutes, but only if the rat does the behavior.Variable Interval (VI) – rewards are given after varying amounts of time that average to a particular interval.VI-15 means one reward after average of 15 min.Effects of Schedule on BehaviorFR leads to steady responding but post reinforcement pauses occur after each reward.VR leads to a high rate of responding with no pauses – never know when reward will occur.FI leads to behavior right before the end of each interval, with goofing off in between.Scallops in the cumulative recordVI leads to the lowest rate of responding.Compound SchedulesMultiple schedules – two or more schedules alternate, each signaled by a different SD.Mixed schedules – schedules alternate but no stimulus signals which type is being used.Chained schedules – completion of one leads to the beginning of a new schedule (with SD).Tandem schedules – liked chained but no SD.Differential High/Low Responding – specifies the behavior and the deadline (interval).ChoiceConcurrent schedules – two different types of behavior are offered, each with its own schedule of reinforcement.Behavior on concurrent schedules follows Herrnstein’s Matching Law.The proportion of behavior allocated to a choice is the same as the proportion of reward offered.B1 / (B1 + B2) = R1 / (R1 + R2) or B1 / B2 = R1 / R2The Law Works for Reward SizeThe amount of responding is proportionate to the relative reward sizes.If V1 and V2 are different reward sizes, thenB1 / B2 = V1 / V2The Matching Law says nothing about what people or rats are thinking.Melioration – a strategy of shifting between two choices until the rewards are equal.A Law for One ChoiceIf the total amount of behavior (B1 + B2) is K, then the rate of responding to a single choice (B1) is:B1 = K x R1 / (R1 + Ro)Ro is the reinforcement rate for some other choice (the reward for doing something else).This is called the Quantitative Law of Effect because it predicts the amount of responding.Implications of the LawAccording to the Law, a particular behavior can be weakened by providing rewards for other behaviors in the environment.Drug abuse is more likely for people who have little other reward in their lives.Problems can be prevented by making sure there are reinforcers for pro-social behaviors.More positive environments can be built.ImpulsivenessDelayed gratification – the willingness to set aside an immediate reward in favor of a long-term, larger reward.People find this difficult to do.Self-control = delaying gratification.Impulsive behavior is more likely when small rewards are imminent (immediate, salient).Hot and Cold ThoughtsImagining the desirable qualities of an immediate reward undermines self control.Distraction by thinking about something unrelated supports self control.Drug abusers have difficult with self-control.Impulsivity may be domain-specific (depend on the kind of reward involved).Although mentalistic, “self-control” is defined in terms of specific behaviors and choices.Behavioral EconomicsNot all reinforcers are alike – substitutability is a continuum (varies).Demand curve – does consumption vary with price?Elastic commodities do, inelastic ones (necessities) do not.Reinforcers can be substitutes, independents, or complements, depending on their demand curves.Theories of ReinforcementDrive Reduction – HullReinforcement occurs when the consequence of behavior reduces a drive (hunger, thirst).Not everything reinforcing reduces a drive, and some reinforcers increase drives (stimulation).Premack’s Principle – behaviors can be reinforcers (not just stimuli such as food).The chance to do a preferred behavior is
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