The effect of induced anxiety on cognition: threat of shock enhances aversive processing in healthy individuals

Abstract

Individuals with anxiety disorders demonstrate altered cognitive performance including (1) cognitive biases towards negative stimuli (affective biases) and (2) increased cognitive rigidity (e.g., impaired conflict adaptation) on affective Stroop tasks. Threat of electric shock is frequently used to induce anxiety in healthy individuals, but the extent to which this manipulation mimics the cognitive impairment seen in anxiety disorders is unclear. In this study, 31 healthy individuals completed an affective Stroop task under safe and threat-of-shock conditions. We showed that threat (1) enhanced aversive processing and abolished a positive affective bias but (2) had no effect on conflict adaptation. Threat of shock thus partially models the effects of anxiety disorders on affective Stroop tasks. We suggest that the affective state of anxiety-which is common to both threat and anxiety disorders-modulates the neural inhibition of subcortical aversive processing, whilst pathologies unique to anxiety disorders modulate conflict adaptation.

Fig. 1

The task was based on that used by both Egner and Etkin (Egner et al., 2008; Etkin et al., 2006). The subject was asked to identify the emotion of the face whilst ignoring the emotion of the word. The task was organised into (eight total) alternating threat (four) and safe (four) conditions, each containing 48 trials (plus 2 extra trials following the shock)

Fig. 2

Healthy individuals demonstrated conflict adaptation under both safe and threat conditions. Enhanced RTs are apparent in incongruent trials preceded by incongruent trials (II), relative to incongruent preceded by congruent trials (CI) (averaged over safe and threat conditions) (a), but a positive affective bias is present only under safe conditions. (B), with enhanced processing of happy relative to fear faces only under safe conditions. RT = reaction time, I = incongruent, C = congruent, F = fearful face, H = happy face, NS = not significant; error bars represent standard errors of the means. *p < .05

Fig. 3

A positive bias (increased accuracy for happy relative to fearful faces) was seen in low, but not in high, scorers on the BIS scale (averaged over conditions; error bars represent standard errors of the means, NS = nonsignificant). *p < .05

Fig. 4

The happier the individuals were, the more errors they made on fear trials under the safe condition relative to under the threat condition [r(30) = .57, p = .001]. VAS = visual analogue scale