Extinction and Stimulus controlChapter 8 – Wintersession 2015
Extinction
Extinction The nonreinforcement of a
previously reinforced response, the result of which is a decrease in the strength of that response Extinguished/ partially
extinguished Important to ensure that the
consequence being withheld is in fact the reinforcer that is maintaining the behavior
Possible side effects
When an extinction procedure is implemented, it is often accompanied by certain side effects
Important to be aware of side effects… Can be misleading May be tricked into thinking not have an
effect, but it does
Side effects of extinction
Extinction burst A temporary INCREASE in the frequency
and intensity of responding is first implemented
Increase in variability Extinction procedure can result in
greater variability in behavior
Side effects of extinction
Emotional behavior E.g. frustration
Aggression Particularly
common during extinction behavior
Side effects of extinction
Resurgence The reappearance during extinction of
other behaviors that once had been effective in obtaining reinforcement E.g. repeating something that had earlier
been effective
Depression Low activity Loss of reinforcement
Resistance to Extinction
Resistance to extinction Extent to which responding persists after
an extinction procedure has been implemented
Number of factors can affect resistance Schedule of reinforcement History of reinforcement Magnitude of the reinforcer Degree of deprivation Previous experience with extinction
Factors that affect extinction
Schedule of reinforcement Most important factor influencing
resistance to extinction Partial reinforcement effect: behavior
that has been maintained on an intermittent (partial) schedule of reinforcement will extinguish more slowly than behavior that has been maintained on a continuous schedule (takes longer to “discover” that
reinforcement is no longer available)
Factors that affect extinction
History of reinforcement Generally, the more reinforcers an
individual has received for a behavior, the greater resistance to extinction
Magnitude of the reinforcer Big food pellet vs. small food pellet
Factors that affect extinction
Degree of deprivation The degree to which an organism is deprived of
a reinforcer also affects resistance to extinction Greater the deprivation greater resistance to
extinction
Previous experience with extinction Sometimes sessions of extinction are alternated
with session of reinforcement Greater the number of prior exposures to
extinction, the quicker the behavior will extinguish during subsequent exposure
Distinctive signal for extinction
Extinction greatly facilitated when there is a distinctive stimulus that signals the onset of extinction Discriminative stimulus for
extinction = faster extinction SΔ
Spontaneous recovery Just because a
response has been extinguished, it doesn’t mean it has been permanently eliminated
Reoccurrence of an extinguished response following a rest period after extinction Function of
discriminative stimuli
Differential reinforcement of other behavior
Process of extinction can be greatly facilitated by both extinguishing the target behavior and reinforcing the occurrence of a replacement behavior
More effective than simple extinction behaviors
Stimulus Control
When a behavior has been consistently reinforced in the presence of a certain stimulus, that stimulus will begin to affect the probability of the behavior SD –signals the availability of the reinforcement
Increases the probability that the behavior will occur under stimulus control – presence of a SD reliability
affects the probability of a behavior
Stimulus generalization
Generalization: the tendency for an operant response to be emitted in the presence of a stimulus similar to the SD
Generalization gradient
Stimulus Discrimination
Reinforcement of responding in the presence of one stimulus and not another stimulus Discriminative stimulus for extinction – a
stimulus that signals the absence of reinforcement
Peak shift effect- the peak of a generalization gradient following discrimination training will shift from the SD to a stimulus that is further removed from the SΔ
Multiple Schedules
Two or more independent schedules presented in sequence, each resulting in reinforcement and each having a distinctive SD
Differs from chain schedule? How? Different response for each SD
Behavioral contrast: a change in the rate of reinforcement on one component of a multiple schedule produces an opposite change in rate of response on another component. Negative contrast effect Positive contrast effect Anticipatory contrast
Fading & Errorless Discrimination
Discrimination training is an effective way to establish stimulus control Has it’s limits Prone to frustration and emotional behavior
Errorless discrimination training: gradual training procedure that minimizes the number of errors and reduces adverse effects of discrimination training
Errorless Discrimination Training
Two aspects:1. Discriminative stimulus for extinction (SΔ)
is introduced early in training, soon after the animal has learned what the SD is
2. SΔ is presented in weak form to begin with and then gradually strengthened
Fading: gradually altering the intensity of the stimulus
Stimulus Control : Additional Apps
Targeting
eliminating target behavior through putting a behavior “on cue”
Creating salient cues
Treating sleep-onset insomnia