Extinction and recovery describe how learned associations in classical conditioning weaken and sometimes reappear. These processes help psychologists explain why conditioned behaviors are not permanent and why relapse can occur after apparent learning has faded.

Extinction in Classical Conditioning

Extinction occurs when a previously conditioned response decreases because the conditioned stimulus is no longer followed by the unconditioned stimulus.

Extinction is identified behaviorally: the organism shows the CR less often, less intensely, or after a longer delay following the CS.

What Extinction Is (and Isn’t)

Extinction is best understood as new learning rather than simple “erasing” of the old association.

• What happens during extinction:

  • The CS becomes a signal that the US is unlikely or absent

  • The CR diminishes across repeated CS-alone trials

• What extinction is not:

  • Forgetting due to the passage of time alone

  • Proof that the original association is completely gone

Because the original learning can still influence behavior, extinction is often described as inhibitory learning (learning that suppresses the CR under certain conditions).

Factors That Influence Extinction (Conceptually)

Even without focusing on other conditioning principles, it helps to recognize broad influences on how quickly extinction occurs:

• Strength of the original conditioning: more robust conditioning often takes longer to extinguish

• Attention and predictability: if the CS strongly captures attention or was a highly reliable predictor, extinction may be slower

• Context sensitivity: extinction learning can be “tied” to the setting in which CS-alone trials occur, making the reduced responding less consistent across environments

Recovery After Extinction

After extinction, conditioned responding can return, demonstrating that extinction did not fully eliminate the underlying learning.

This figure compares the return of conditioned responding (“renewal”) across different context sequences (e.g., acquisition in Context A, extinction in Context B, test back in Context A = ABA renewal). It highlights that responding can rebound when the CS is tested outside the extinction context, aligning with the idea that extinction often reflects new, context-bound inhibitory learning rather than erasure. Source

Spontaneous recovery is typically weaker than the original CR, and it often fades again quickly if the CS continues to appear without the US.

This graph plots strength of the conditioned response (CR) over time, showing the classic sequence: acquisition (CR rises with CS–US pairings), extinction (CR declines during CS-alone trials), a pause, and then spontaneous recovery followed by renewed extinction. Visually, it reinforces the idea that extinction reduces responding but does not permanently eliminate the underlying association. Source

Why Spontaneous Recovery Happens

Spontaneous recovery supports a key interpretation: extinction creates a competing memory (“CS → no US”) that can weaken over time or fail to control behavior in all situations. With the passage of time, the influence of extinction learning may be reduced, allowing the earlier association (“CS → US”) to show itself again.

How Extinction and Spontaneous Recovery Fit Together

These processes are often observed in a predictable sequence:

• Conditioned responding established (CR reliably follows CS)

• Extinction phase: repeated CS without US reduces CR

• Delay/rest period

• Test: CS presented again may produce spontaneous recovery

• Further CS-alone trials typically reduce the recovered CR again

In practical terms, extinction lowers the probability of the CR, while spontaneous recovery shows that the probability can increase again under certain timing conditions.

Studying Extinction and Recovery

Researchers operationalize these concepts by measuring changes in the CR across time and conditions.

• Common indicators of extinction:

  • Decline in CR frequency

  • Reduced CR magnitude

  • Increased latency (slower onset of CR after CS)

• Common indicators of spontaneous recovery:

  • Increase in CR after a delay, compared to responding at the end of extinction

These measurements help distinguish temporary suppression from more durable decreases in conditioned responding, which is central to understanding why learned reactions may reappear even after they seem to be “gone.”