The presence of threat affects saccade trajectories

In everyday life, fast identification and processing of threat-related stimuli is of critical importance for survival. Previous studies suggested that spatial attention is automatically allocated to threatening stimuli, such as angry faces. However, in the previous studies the threatening stimuli were not completely irrelevant for the task. In the present study we used saccadic curvature to investigate whether attention is automatically allocated to threatening emotional information. Participants had to make an endogenous saccade up or down while an irrelevant face paired with an object was present in the periphery. The eyes curved away more from the angry faces than from either neutral or happy faces. This effect was not observed when the faces were inverted, excluding the possible role of low-level differences. Since the angry faces were completely irrelevant to the task, the results suggest that attention is automatically allocated to the threatening stimuli, which generates activity in the oculomotor system, and biases behaviour.