Retrieval stopping in delayed fear extinction

Intrusive thoughts after trauma are common and may reflect conditioned responses to trauma cues. Fear extinction reduces such responses, and its timing affects underlying mechanisms, with delayed extinction promoting inhibitory learning. Recent models suggest that active retrieval stopping may also contribute to extinction via inhibitory control. The present study used a modified Extinction-Think/No-Think paradigm to target the inhibitory retrieval mechanism of extinction. This within-subjects 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 h, they underwent extinction while practising retrieval stopping. We hypothesised that unconditioned stimulus (US) expectancy would decrease more for objects in the retrieval stopping (No-Think) condition compared to standard extinction (View) over time. Results showed that US expectancy decreased across extinction, but retrieval stopping was not superior to standard extinction. Bayesian analysis provided weak evidence in favour of the null hypothesis, that intentional retrieval stopping does not enhance extinction beyond standard procedures. Future research should explore its long-term effects on fear recovery and generalisation.