Although contemporary treatments for anxiety disorders are very efficient in reducing anxiety, return of fear after successful treatment is common which signifies a need for interventions that have a more enduring outcome. A recent laboratory study suggested that novelty-facilitated extinction, a simple modification of standard extinction which involves presenting a novel non-aversive stimulus during extinction, prevents spontaneous recovery, one laboratory analogue of return of fear. The current study assessed whether novelty-facilitated extinction can also prevent reinstatement, a second laboratory analogue of return of fear. Following differential fear conditioning, one group of participants underwent standard extinction training whereas the second was presented with a novel tone after the conditional stimulus that previously predicted the aversive unconditional stimulus (US). Three presentations of the USs alone reinstated differential electrodermal fear responses after standard extinction, but not after novelty-facilitated extinction. Moreover, replicating previous findings, the extent of return of fear was correlated with self-reported intolerance of uncertainty after standard extinction, but not after novelty-facilitated extinction. These results support the proposal that novelty-facilitated extinction training can reduce the extent of return of fear.

Relapse of fear after successful intervention is a major problem in clinical practice. However, little is known about how it is mediated. The current study investigated the effects of instructed extinction and removal of the shock electrode on electrodermal responding (Experiment 1), fear potentiated startle (Experiment 2), and a continuous self-report measure of conditional stimulus valence (Experiments 1 and 2) in human differential fear conditioning. Instructed extinction and removal of the shock electrode resulted in the immediate reduction of differential fear potentiated startle and second interval electrodermal responding, but did not affect self-reported conditional stimulus valence. A separate sample of participants (Experiment 3) who were provided with a detailed description of the experimental scenario predicted the inverse outcome, reduced differential stimulus evaluations and continued differential physiological responding, rendering it unlikely that the current results reflect on demand characteristics. These results suggest that the negative valence acquired during fear conditioning is less sensitive to cognitive interventions than are the physiological indices of human fear learning and that valence reduction requires extended exposure training. Persisting negative valence after cognitive intervention may contribute to fear relapse after successful treatment.

Instructed extinction is an experimental manipulation that involves informing participants after the acquisition of fear learning that the unconditional stimulus (US) will no longer be presented. It has been used as a laboratory analogue to assess the capacity of cognitive interventions to reduce experimentally induced fear. In this review, we examine and integrate research on instructed extinction and discuss its implications for clinical practice. Overall, the results suggest that instructed extinction reduces conditional fear responding and facilitates extinction learning, except when conditional stimulus valence is assessed as an index of fear or when fear is conditioned to images of animal fear-relevant stimuli (snakes and spiders) or with a very intense US. These exceptions highlight potential boundary conditions for the reliance on cognitive interventions when treating fear in clinical settings. What is already known about this topic?1. Instructed extinction is a cognitive manipulation used in human fear conditioning research. 2. Instructed extinction involves informing the participants that US presentations will cease. 3. Instructed extinction has been used in a wide variety of research over the last 60 years. What this topic adds?1. Instructed extinction facilitates extinction learning in the majority of cases. 2. Instructed extinction does not affect conditional stimulus valence, fear conditioned to images of snakes and spiders, or fear conditioned with a very painful US. 3. Instructed extinction effects could have clinical applications and should be examined in a clinical setting.