Potential threat attracts attention and interferes with voluntary saccades.

Several studies have shown that threatening stimuli are prioritized by the visual system. In the present study we investigated whether a stimulus associated with a threat of electrical shock attracts attention and accordingly interferes with the execution of voluntary eye movements to other locations. In 2 experiments, we showed that when a fear-conditioned and a neutral stimulus were presented simultaneously, voluntary saccades were initiated faster toward fear-conditioned compared with neutral stimuli. Moreover, saccades often erroneously went to the location of threat even when a saccade to a different location was required. This implies an automatic shift of attention to a fear-conditioned stimulus that interferes with saccade execution. The same pattern of results was found for a neutral stimulus that was always presented together with the fear-conditioned stimulus and consequently itself became associated with threat. The current results indicate that threatening stimuli attract visual attention and subsequently bias saccade target selection in a reflexive fashion.