Ch. 8: Extinction and Stimulus Control

Side effects of extinction

• Extinction burst

• Increase in variability

• Emotional behavior

• Aggression

• Resurgence

• Depression

Extinction burst

• Temporary increase in the frequency and intensity of responding when extinction is first implemented

• Scientific example: a rat is reinforced every fourth lever press (FR 4 schedule) → when extinction is implemented, the rat will initially react by pressing the lever both more rapidly and more forcefully

• Real world example: when the washing machines at my freshman year dorm would not start after I paid the fee on the machine, I kept pressing the button several times in a row, with increasing force each time I pressed it…

Increase in variability

• If the rat typically pressed the lever with its right paw to get food, it might now try pressing it with its left paw

• If the washing machine was not working again even after I paid, I would hold down the button to see if it would start

Emotional behavior

• An emotional response to an extinction procedure – agitation, distress, anxiety, etc.

• Scientific example: a rat pacing or squeaking when a lever stops dispensing food

• Real world example: A child might receive attention whenever they throw a tantrum. A parent might implement extinction by no longer giving the child attention. The child may start feeling anxious and start hyperventilating.

Aggression

• A type of emotional behavior that is common during an extinction procedure  (Extinction-induced aggression or frustration-induced aggression)

• Scientific example: a rat attacks another rat in the same cage, chew on the bars of the cage, or even aggressively scratch at the lever when the lever stops dispensing food

• Real world example: if the child does not receive the attention they want, they may start hitting, kicking, or throwing objects

Resurgence

• Reappearance of other behaviors during extinction that had previously been effective in obtaining reinforcement

• Scientific example: Hull trained rats to run a 20ft pattern → 40ft pattern through a maze

  • Post extinction: rats persisted with the 40ft pattern → 20ft pattern → quitting

• Real world example: A student used to pull all-nighters to cram study before an exam but shifts to consistent studying habits (reinforced by better grades and less stress)

  • Post extinction: reverts to pulling all-nighters and cramming

Depression

• Extinction can lead to depressive-like symptoms

• Depression → loss of reinforcement

• Rats run down an alleyway for food → assessment of activity level in an open field test

• With extinction implemented on the alleyway task:

• Real world example: someone dies, family and friends essentially experience extinction and will become depressed

Resistance to extinction

• The extent to which responding persists after an extinction procedure has been implemented

• A response that is very persistent is said to have high resistance to extinction

• A response that disappears quickly is said to have low resistance to extinction

  • Ex: a dog that continues to beg for food at the dinner table for 20 mins. after everyone has stopped feeding it has a much higher resistance to extinction than does a dog that stops begging after 5 mins.

Factors to resistance to extinction

• Schedule of reinforcement

• History of reinforcement

• Magnitude of the reinforcer

• Degree of deprivation

• Previous experience with extinction

• Distinctive signal for extinction

• Spontaneous recovery

Schedule of reinforcement

• Most important factor influencing resistance to extinction

• Partial reinforcement effect

• Resistance to extinction is particularly strong when behavior has been maintained on a variable interval or variable ratio schedule

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

• Ex: lever pressing that has been reinforced on an FR 10 schedule will take longer to extinguish than lever pressing that has been reinforced on a CRF (FR 1) schedule

• The less frequent + less predictable the reinforcer, the longer it takes the person or animal to “discover” that reinforcement is no longer available

• Helps account for certain types of annoying or maladaptive behaviors

History of reinforcement

• The more reinforcers that an individual has received for a behavior, the greater the resistance to extinction

  • Ex: lever pressing will extinguish more rapidly if a rat has previously earned only 10 reinforcers for lever pressing than if it has earned 100 reinforcers

• Much easier to extinguish an unwanted behavior (i.e. whining for candy) when it first becomes evident

Magnitude of the reinforcer

• Large-magnitude reinforcers sometimes result in greater resistance to extinction than small-magnitude reinforcers

  • Ex: lever pressing might take longer to extinguish following a training period in which each reinforcer consisted of a large pellet of food than if the reinforcer were a small pellet of food 

    • Could also take longer to extinguish if the reinforcer was a highly preferred food item than if it were a less preferred food item

• Effect of reinforcer magnitude on resistance to extinction is not entirely consistent → smaller reinforcers can sometimes result in greater resistance to extinction

  • Ex: a dog’s behavior of begging at the dinner table might extinguish more easily if you first spend several days feeding it small bites of less preferred morsels

Degree of deprivation

• The greater the level of deprivation, the greater the resistance to extinction

• Ex: a rat that is only slightly hungry will cease lever pressing more quickly than a rat that is very hungry

Previous experience with extinction

• When sessions of extinction are alternated w/ sessions of reinforcement, the greater the # of exposures to extinction, the greater the behavior will extinguish during subsequent exposures

• Ex: if a rat experiences several sessions of extinction randomly interspersed w/ several sessions of reinforcement, it will eventually learn to stop lever pressing soon after the start of an extinction session

Distinctive signal for extinction

• Extinction occurs more quickly when there is a distinctive stimulus that signals the onset of extinction

• Such stimulus = distinctive stimulus for extinction

• If a parent consistently ignores a child’s tantrums when they sit down w/ a book in hand, the child learns that tantrums will not be reinforced when the parent is reading

Spontaneous recovery

• The reappearance of an extinguished response, despite the continued absence of reinforcement, following a rest period after extinction

  • Ex: we extinguish a rat’s behavior of lever pressing → the next day, when we place the rat back in the experimental chamber, it will probably commence lever pressing again

    • Forgot that lever pressing no longer produces food

    • Behavior will likely be weaker than it was at the start of the extinction phase the day before and will extinguish more quickly → we continue to withhold reinforcement

      • Process might repeat itself several times → each recovery gets weaker and weaker (eventually spontaneous recovery won’t occur)

• May be a function of discriminative stimuli

  • Ex: the rat’s experience of being taken from the home cage, weighed, and placed in an operant chamber is a signal for the availability of food 

    • Will stop pressing lever when it realizes that it won’t receive food when it repeatedly is exposed to these events

Differential reinforcement of other behavior (DRO)

• Extinguishing the target behavior and reinforcing the occurrence of a replacement behavior

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

  • Ex: you extinguish a child’s habit of whining for candy but also explicitly reinforce alternative behaviors, especially the behavior of being well-mannered

    • They can still obtain candy, but only if they exhibit an appropriate pattern of behavior

    • The candy can be gradually phased out or replaced by a healthier treat (as the appropriate behavior becomes firmly established)

• More effective than simple extinction procedures → weakened both by:

  • The lack of reinforcement for that behavior

  • The reinforcement of alternative behaviors that come to replace it

Functional communication training (differential reinforcement of functional communication)

• Many unwanted behaviors occur because the child is attempting to attain an important reinforcer (i.e. attention) but is doing so inappropriately

• The behavior is clearly and appropriately communicating one’s desired is differentially reinforced