Overgeneralization of fear, but not avoidance, following acute stress

Anke Lemmens,Tom Beckers,Pauline Dibbets,Sahaj Kang,Tom Smeets

doi:10.1016/j.biopsycho.2021.108151

Abstract

Research has demonstrated the spreading of fear from threat-related stimuli to perceptually similar, but innocuous, stimuli. Less is known, however, about the generalization of avoidance behavior. Given that stress is known to affect learning and memory, we were interested in the effect of acute stress on (over)generalization of fear and avoidance responses. On the first day, one geometrical shape was paired with a mild electrical stimulus (CS+), whereas another shape was not (CS−). One day later, after participants had been exposed to the Maastricht Acute Stress Test or a control task, generalization of avoidance responses and fear (shock expectancy and skin conductance responses) was tested to a range of perceptual generalization stimuli. Generalization gradients were observed across different outcome measures. Stress enhanced generalization of shock expectancy to the stimulus most similar to the CS+. Our findings confirm that stress can affect the generalization of fear, but further studies are warranted.

Highlights

A key characteristic of many stress- and anxiety-related disorders is the excessive spreading of fear from genuine threat-related stimuli to similar but innocuous cues, a phenomenon called fear over generalization (Lissek & Grillon, 2010; Lissek et al, 2005)
There was a significant difference in distress tolerance (F(1, 48) = 4.93, p = .03), indicated by higher mean Distress Tolerance Scale (DTS) scores (M = 3.68) in the stress group compared to the no-stress control group (M = 3.33)
The aim of the current study was to examine whether participants who were exposed to acute stress one day after fear acquisition dis played greater overgeneralization of fear responses and increased reli ance on avoidant safety behaviors compared to non-stressed controls

Summary

Introduction

A key characteristic of many stress- and anxiety-related disorders is the excessive spreading of fear from genuine threat-related stimuli to similar but innocuous cues, a phenomenon called fear over generalization (Lissek & Grillon, 2010; Lissek et al, 2005). The generalization from threat-associated stimuli to perceptually related stimuli is often investigated in experiments that expose participants to circles of different sizes or colors (e.g., Lissek et al, 2008; Lommen, Engelhard, & van den Hout, 2010; for a review on fear generalization, see Dymond, Dunsmoor, Vervliet, Roche, & Her mans, 2015). Fear responses typically generalize to the intermediate stimuli in accordance with their position between the CS+ and CS− (Lissek et al, 2008) and the decrease in fear responses as stimuli differ more from the CS+ is less steep in clinical anxiety patients compared to the general population (Dymond et al, 2015)

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