Study Notes on Extinction of Conditioned Behavior

PSYC 351: Fundamentals of Learning

Chapter 10: Extinction of Conditioned Behaviour

Outline

• Extinction Background

• Recovery from Extinction

  • Spontaneous Recovery

  • Reinstatement

  • Renewal

• Enhancing Extinction

Extinction Background

What is Extinction?

• Definition: Extinction is a process involved in learning where conditioned behaviours diminish in response due to the omission of reinforcing stimuli.

• Learning is crucial as it helps individuals adapt to changing environments, and the loss of conditioned responses is also beneficial.

• Key points about reinforcement:

  • Reinforcement schedules do not persist indefinitely.

• Extinction occurs due to:

  • Absence of the Unconditioned Stimulus (US) in Pavlovian conditioning.

  • Absence of the reinforcer in instrumental conditioning.

The Procedure of Extinction

• Extinction results from a specific procedure where the reinforcing stimuli or US is omitted.

• Importance: Understanding extinction is pivotal for developing therapeutic treatments for various conditions such as phobias and PTSD.

• In Pavlovian Conditioning: Involves repeated presentation of the Conditioned Stimulus (CS) without the US.

• In Instrumental Conditioning: Involves not presenting the reinforcer when the instrumental response occurs.

Breaking the Conditioned Association

• Breaking the association between the CS and US can extinguish the CS→Conditioned Response (CR) reflex by:

  • Repeatedly presenting the CS alone without the US.

  • Initially, the CS generates strong CRs, but with repetition, the effectiveness diminishes, resembling the start of training.

Nature of Extinction

• Extinction inhibits but does not erase the CS/US connection.

• Various factors (such as stress, new contexts, or time lapse) may reactivate the CS, indicating that the conditioned memory persists even post-extinction.

• Extinction does not erase the CS/US connection, just inhibits it:

  • Stress, new context, and/or passage of time can make the CS effective again!

  • This suggests that the classically conditioned memory survived extinction

• Also, EXTINCTION IS NOT UNLEARNING

  • A new relationship is being learned… it doesn’t erase the previous learning, but is more of a hierarchical learning (a new learning association is put on top of the old one)

• And CS = 0 IS NOT CS = ?; one is that the CS no longer has predictability of the US, and the other is that you don’t know what CS is predictive of

When is Extinction Useful?

• Extinction can lead to the reduction of conditioned behaviours in changing environments, such as:

  • Non-functioning vending machines.

  • Ending relationships.

  • Changes in context that alter response (e.g., interpreting loud noises in non-combat environments).

  • In shaping, earlier behaviours are no longer reinforced.

  • In foraging scenarios, abandonment of a resource when it becomes unavailable (e.g., a dried-up watering hole).

Clinical Importance of Extinction

1. Elimination of Problematic Behaviours:

   • For example, identifying and removing events that reinforce a child's disruptive behaviour leads to a decrease in such actions.

2. Exposure Therapy:

   • Used for fear, phobias, and addiction through controlled exposure to feared objects without reinforcement.

Behavioural Effects of Extinction

1. Decreases target behaviour, but increases response variability.

• Neuringer, 2001

  • Rats, 3 responses on 3 levers for food

  • Group 1

2. There is often a temporary increase in the frequency of the original response, termed the extinction burst.

• Example: Observations in experimental settings indicated increased responses (e.g., lever pressing) during initial extinction sessions before decay.

Distinction from Other Concepts

• Extinction ≠ Forgetting:

  • Forgetting occurs due to the passage of time rather than repeated CS presentations without the US or lack of reinforcement.

• Extinction ≠ Habituation:

  • Habituation describes a decline in unlearned behaviour, while extinction involves the decline of learned behaviour.

• Emotional responses during extinction can lead to frustration, potentially resulting in aggression due to reinforcement withdrawal.

Recovery from Extinction

Original Memory After Extinction

• The process of extinction is complex and suggests that original learning may persist even when overt behaviours decline.

• The Rescorla-Wagner model posits that extinction can be viewed as unlearning or as the learning of new associations which inhibit previous responses.

Evidence of Recovery

• Spontaneous Recovery:

  • The reappearance of the conditioned response after a period of rest post-extinction highlights that learned behaviours are often suppressed rather than unlearned.

• Reinstatement:

  • Recovery occurs after exposure to the US following extinction, emphasizing the role of the US in recovering conditioned responses. - Example: In fear conditioning studies, exposure to fear-inducing stimuli without reinforcement demonstrated reinstatement of fear responses.

• Renewal:

  • Recovery arises when the contextual cues during extinction change, which is significant in clinical settings as behaviours extinguished in therapy may return in normal environments.

• Evidence from studies demonstrates how changing context can reactivate extinguished responses, indicating incomplete unlearning.

Implications of Recovery Effects

1. Extinction leads to learning an episodic meaning about the CS, specific to the context in which the extinction occurred.

2. Contextual cues following extinction are crucial, as they retrieve the relevant meanings of the CS, thus acting as ‘occasion-setters’ for certain behaviours.

Enhancing Extinction

Exposure Therapy Techniques

• Manipulations can reduce renewal, spontaneous recovery, and reinstatement effects during exposure therapy.

Strategies to Enhance Extinction

1. Increasing Extinction Trials: More trials result in stronger suppression of conditioned behaviours.

2. Intertrial Interval Considerations: Longer intervals between trials produce more lasting suppression of conditioned responses.

3. Using Multiple Contexts for Extinction: Conducting extinction in varied contexts reduces fear renewal in cases such as animal studies (e.g., spider anxious students).

4. Extinction Reminders: Presenting stimuli that remind individuals of the extinction context (CS-no US associations) helps maintain the learned extinction behavior.

5. Compounding Extinction Stimuli: Producing overexpectations by presenting two extinguished stimuli together can strengthen the extinction effect.

Paradoxical Extinction Effects

Overtraining Extinction Effect

• More extensive reinforcement training before extinction leads to more rapid extinction, associated with greater frustration due to higher expectations of reinforcement.

Partial Reinforcement Extinction Effect (PREE)

• Refers to the greater persistence observed in behaviours during extinction after partial reinforcement compared to continuous reinforcement. Reasons include:

  1. Discrimination Hypothesis: Individuals more readily notice the absence of reinforcement following continuous reinforcement training (CRF).

  2. Learned Persistence: Training under partial reinforcement leads participants to persist despite frustration due to a conditioned response to non-reward.

Summary of Extinction Concepts

1. Extinction comprises two main behavioural changes: a decrease in conditioned responses and an increase in response variability.

2. Responses are context-specific and involve learning to suppress conditioned behaviours rather than forgetting them outright.

3. Overtraining can quicken response declines, while partial reinforcement slows them down.

4. Recovery mechanics (spontaneous recovery, renewal, reinstatement) demonstrate an intricate relationship between extinction and memory retention.

5. Enhancements in extinction, such as increasing trial frequency and using contextual variability, can augment its effectiveness in therapeutic settings.