Cautiously vigilant: A new behavioural measure of threat evaluation during visual search tasks

Previous reports of faster responses to threatening compared to benign stimuli in visual search tasks, have argued that threatening targets are faster to engage, and slower to disengage, attention than benign targets. This study re-interprets previous findings and resolves inconsistencies by replacing the theory of differential disengagement of attention, with one of differential caution. It introduces a novel 'caution score' that appears to be sensitive to the level of threat implied by the target image, but immune to other stimulus features (target-distracter similarity and threat status of distracters) known to affect reaction time. As well as locating threatening targets faster than benign targets, participants were also faster, more accurate and more cautious to detect lethal spiders compared to non-lethal spiders; and even more cautious again if the spiders were presented on a person's hand. These results suggest that mechanisms of attention and threat evaluation interact during visual search tasks producing behaviour that is sensitive to the target's implied threat level and the context in which that target is presented.