4 - (SYM 15) The Influence of Affect and Stimulus Valence on Fear Extinction and Return of Fear

            Extinction learning, or confronting a feared stimulus without the feared consequence, is thought to underlie effective exposure-based treatments for anxiety disorders. In essence, extinction learning allows individuals to form “safety” memories of the relationship between the feared stimulus and feared outcome which then compete with the original “fear” memories. Fear conditioning paradigms provide a translational research framework for investigating factors that may enhance extinction learning memories and thus reduce return of fear.

The current study evaluated the effects of two such factors, stimulus valence and affect, in a 3-day fear conditioning paradigm. Fifty-three adults (M(SD) age=20.1 (2.5), 49% female, 59% white) met final inclusion criteria. Participants underwent habituation and fear acquisition on Day 1. They were randomized to receive positive affect induction (PAI) or negative affect induction (NAI) before extinction on Day 2. Day 3 consisted of extinction retest, reinstatement, and reinstatement test. We predicted that PAI would increase both positive affect and CS+ valence compared to NAI. We further hypothesized that individuals receiving PAI would evidence enhanced extinction learning and reduced return of fear.

Preliminary analyses indicated that habituation, acquisition, and extinction largely occurred as expected. Additionally, the PAI and NAI conditions influenced affect in the expected directions on Day 2. Against predictions, the NAI group evidenced a greater increase 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, or increased likelihood of selecting a CS+ corresponding stimulus in an implicit valence task after extinction. 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 producing greater extinction learning compared to PAI for CS-US contingency ratings but not for differential skin conductance responses.

Overall, findings did not support the hypothesis that positive affect enhances extinction or reduces return of fear compared to negative affect. It may be the case that certain aspects of positive affect (e.g., arousal) are required to result in enhanced extinction. The observed absence of return of fear has implications for the design of future fear conditioning paradigms.