Ch.8 Extinction/ Stimulus control

introduction: Review of extinction

  • (extinction)–nonreinforcement of previously reinforced response; results in decrease in the strength response

  • Procedure of extinction is nonreinforcement of previously reinforced response ← →Process of extinction is resultant decrease in response strength

Side effects of extinction    

  • (extinction Burst)–temporary increase in frequency and intensity of responding when extinction first implemented

  • (increase in variability)–increase in variability of a behavior (example = frustration, aggression, depression)

  • (resurgence) –reappearance during extinction of other behaviors that had once been effective in obtaining reinforcement

Resistance to extinction

  • Extent to which responding (persists) after extinction procedure has been implemented (can be high or low)

    • (partial reinforcement effect)–behavior maintained on intermittent/partial reinforcement schedule will extinguish more slowly than behavior maintained on continuous schedule

    • (history) of Reinforcement–the more reinforcers received = greater resistance to extinction

    • (magnitude) of the Reinforcer–large reinforcers sometimes result in greater resistance to extinction than small reinforcers

    • (degree of deprivation)–the greater the level of deprivation, the greater the resistance to extinction

    • Previous (experience)with Extinction–the greater the number of exposures to extinction, the quicker the behavior will extinguish

    • (distinctive signal) for Extinction–extinction facilitated when there is a distinctive stimulus that signals the onset of extinction

(Spontaneous recovery)

  • Reappearance of an extinguished response following a rest period after extinction

(Differential Reinforcement) of other behavior(DRO)

  • Reinforcement of any behavior other than the target behavior that is being extinguished

    • More effective than simple extinction procedures

    • Reduces unwanted side effects of extinction

  • (Functional communication training)(differential reinforcement of functional communication)–where behavior of clear and appropriate communication is differentially reinforced

Stimulus Control

  • Presence of discriminative stimulus reliably affects probability of the behavior

  • Stimulus Generalization–tendency for operant response to be emitted in presence of stimulus similar to SD

    • (generalization gradient)–tendency to generalize across different stimuli

    • (stimulus discrimination)–tendency for operant response to be emitted more in the presence of one stimulus than another

    • (discrimination training)–reinforcement of responding in presence of SD and not another

(Peak shift)effect

  • Peak of generalization gradient following discrimination training will shift from the SD to a stimulus further removed from S∆ during discrimination

    • Possible Explanations: -Respond in terms of relative rather than absolute values -SD has acquired negative properties of S∆

(Multiple schedules/ and behavioral contrast)

  • (multiple schedules)–two or more independent schedules presented in sequence; each resulting in reinforcement having distinctive SD

    • Differs from a chained schedule; chained schedule requires that all of the component schedules be completed before reinforcer

  • (behavioral contrast)–occurs when change in rate of reinforcement on one component of multiple schedule produces opposite change in the rate of response on another component

Contrast effects

  • (Negative) contrast effect

    • Increase in rate of reinforcement on one component

    • Produces a decrease in rate of response on the other component

  • (positive) contrast effect

    • Decrease in rate of reinforcement on one component

    • Increases rate of response on the other component

(Anticipatory)Contrast

  • Rate of response varies inversely with an upcoming (“anticipated”) change in the rate of reinforcement

Discrimination Training has its Limits

  • (Errorless discrimination) training

    • Gradual training procedure that minimizes errors and reduces adverse effects of discrimination training

    • Two aspects:

      • S introduced early in training, soon after the animal learns to respond appropriately to SD

      • S∆ presented in weak form and gradually strengthened

    ← Good for rote learning of basic facts that are unlikely to change

  • (Fading)

    • Process of gradually altering the intensity of a stimulus

    • Fewer adverse side effects

    • Greater flexibility when what is learned has to be modified later

← Good for material requiring greater flexibility

Stimulus Control

  • Animal Training --- Is learning between the animal and the trainer a 2-way street?

    • Targeting trains an animal to approach and touch particular object; then move the object to desired response (example = dolphin touching nose to stick)

    • Example = Dog barking. By putting a behavior “on cue,” the behavior is less likely to occur in the absence of cue.

Summary

  • Extinction

    • Nonreinforcement of previously reinforced response

    • Side Effects = extinction burst, increase in variability, resurgence

    • Resistance to Extinction– persistence after extinction procedure

    • Spontaneous Recovery– reappearance of an extinguished response following a rest period after extinction

    • DRO–more effective and lessens side effects

  • Stimulus control

    • Peak Shift Effect

    • Multiple Schedules–2 or more

    • Behavior Contrast–negative and positive

    • Anticipatory Contrast–varies inversely with expected change

    • Errorless Discrimination Training–rote memory

    • Fading–flexible

    • Animal Training–uses targeting and cues