The influence of affect and stimulus valence on fear extinction and return of fear
Embargo Date
2026-06-30
OA Version
Citation
Abstract
Fear conditioning paradigms provide a translational research framework for investigating factors that may enhance extinction learning and reduce return of fear. The current study experimentally evaluated the effects of two factors, stimulus valence and affect, in a three-day paradigm. One-hundred and fifty adults were recruited; approximately one third (N = 53, M(SD) age=20.1 (2.5)) met final inclusion criteria. Day one procedures included habituation and fear acquisition: pairing one conditioned stimulus (i.e., the CS+) with an aversive stimulus. Participants were randomized to positive affect induction (PAI) or negative affect induction (NAI) before extinction on day two. Day three consisted of extinction retest, reinstatement, and return of fear test. I predicted that PAI would increase both positive affect and CS+ valence relative to NAI. I further hypothesized that individuals receiving PAI would evidence less return of fear at reinstatement, faster extinction learning, and increased likelihood of selecting a CS+ corresponding stimulus in an implicit valence task. Primary study outcomes were differential skin conductance responses (SCRs) and self-reported CS-US contingency ratings (i.e., degree to which the aversive stimulus was expected to follow each conditioned stimulus).Preliminary analyses indicated that habituation, fear acquisition, and extinction largely occurred as expected. Additionally, the PAI and NAI conditions influenced affect in the expected directions on day two. Against predictions, the NAI group evidenced greater increases in CS+ valence than the PAI group following affect induction.
Concerning the core outcomes, none of the hypotheses were supported: PAI did not result in less return of fear at reinstatement, faster extinction learning, nor increased likelihood of selecting a CS+ corresponding stimulus in an implicit valence task. The reinstatement-focused findings were complicated by participants not evidencing return of fear at reinstatement test on average. Unexpectedly, exploratory analyses indicated a trend toward NAI resulting in greater extinction learning compared to PAI for CS-US contingency ratings but not for differential SCRs.
Overall, findings did not support the hypothesis that positive affect enhances extinction or reduces return of fear compared to negative affect. The observed absence of return of fear in the current study has implications for the design of future fear conditioning paradigms.
Description
2024