Retrieval Stopping in Delayed Fear Extinction and the Role of Chronic Thought Suppression

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 while immediate extinction represents a form of unlearning. Recent models suggest that extinction engages inhibitory control mechanisms and that active retrieval stopping contributes to extinction. 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 and whether individual differences in chronic thought suppression influence this effect. 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 control (Baseline) and standard extinction (View) over time. Additionally, we expected that a stronger tendency to suppress thoughts in daily life would predict these differences. The results showed that retrieval stopping led to a greater reduction in US expectancy than the decrease observed for Baseline objects but was not superior to standard extinction. Furthermore, higher chronic thought suppression predicted a larger retrieval-stopping-induced decrease in US expectancy. These findings suggest retrieval stopping may aid fear reduction, particularly for individuals prone to chronic thought suppression. However, it may not be a superior alternative to standard extinction. Further research should investigate the long-term effects of retrieval stopping on fear recovery and generalisation.