Abstract
Efficient processing of complex social and biological stimuli associated with threat is crucial for survival. At present there are two major hypotheses about attentional deployment to the threat-related stimuli (Weierich, Treat & Hollingworth, 2008). According to the vigilance-avoidance theory threatening stimuli initially capture attention, but are avoided at the later stage. According to the delayed disengagement hypothesis threatening stimuli do not capture attention, but if attended they are monitored more extensively and delay disengagement of attention from their location. To resolve this controversy the present study employed a novel paradigm that allowed us to measure the disengagement and avoidance using eye movements. In the first experiment we showed that participants were slower to make an eye movement away from an irrelevant angry face presented at fixation than from either a neutral or a happy face. This finding supports the notion that delay in disengaging attention from threat is an important component of processing threatening information. To relate the disengagement to avoidance in a follow-up experiment participants were asked to make a saccade away from a face, but on some trials they were also asked to either return their gaze to the face or to make an eye movement to a new location. These “return” saccades were expected to be executed slower than saccades to the new location due to the well-known inhibition of return (IOR). The question was whether IOR would be greater for the angry faces. The results showed that participants were again slower to disengage the eyes from an angry face but importantly, the IOR was greater for angry faces suggesting that participants avoided returning their gaze to the angry face. The results provide a first demonstration of a direct link between the delayed disengagement and avoidance of threatening stimuli and bridges the gap between the two major theories.
Netherlands Organization for Scientific Research (NWO-Veni 451-08-017) grant to A.V.B.