Retrieval Stopping in Delayed Fear Extinction

Intrusive thoughts following traumatic experiences are common and may be conditioned responses to trauma cues. Fear extinction reduces these responses. The timing of extinction influences its underlying mechanisms, with delayed extinction facilitating inhibitory learning. Recent models suggest that active retrieval stopping contributes to extinction via inhibitory control mechanisms. Using a modified Extinction-Think/No-Think paradigm to target the inhibitory retrieval mechanism of extinction, this study examines whether retrieval stopping enhances delayed fear extinction. Fifty-nine healthy participants learned aversive object-scene pairs followed by a fear acquisition phase. After 24 hours, participants underwent extinction whilst practising retrieval stopping. We hypothesised greater reductions in unconditioned stimulus (US) expectancy for objects following retrieval stopping (No-Think) than standard extinction (View) over time. The results showed that US expectancy decreased during extinction, though retrieval stopping was not superior to standard extinction. Bayesian analysis provided weak evidence that intentional retrieval stopping is not a superior alternative to standard extinction. Further research should investigate the long-term effects of retrieval stopping on fear recovery and generalisation.