Abstract
Stimuli signalling reward capture attention even when non-salient and task-irrelevant. Such attentional bias is value-dependent, meaning that stimuli signalling higher reward induce greater capture. Stimuli signalling threat also capture attention, but whether threat intensity modulates the magnitude of attentional capture by associated stimuli remains unclear. We manipulated threat intensity using electric shocks, loud white noise and a combination of both to address this question. Doing so also allowed us to examine whether multisensory integration potentiates attentional bias. Indeed, threat perception in real life is a multisensory experience – for example, sight of a predator may be accompanied by a growling sound – and such integrative threat signals are known to modulate attentional capture. In a training phase, participants generated a speeded saccade to a square, the colour of which signalled either an electric shock, loud white noise, the two outcomes combined, or no outcome. In a test phase, a square (distractor) and a circle (target) were presented simultaneously; the same colours were used as during training, fully crossed and counterbalanced with respect to target and distractor status. Participants were tasked with making a speeded saccade to the circle. We found that test phase RTs were slower when there was a threat-signalling distractor than when there was a threat-signalling target, indicative of attentional bias towards threatening stimuli. However, there was no difference in the magnitude of attentional bias between the three aversively conditioned stimuli, with Bayes factors supporting the null hypothesis. Interestingly, subjective ratings of perceived aversiveness indicated that the combined outcome was most aversive for a majority of participants. Together, these results suggest that threat-induced attentional bias is independent of threat intensity, and that although multisensory integration augments perceived aversiveness, it does not potentiate attentional bias to threatening stimuli.