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Abstract:
Other people's gaze direction and emotional expression are
important social signals that can influence orienting of visual
attention in normal observers. Functional neuroimaging in humans
and neurophysiological recording in monkeys suggest that the
processing of gaze and facial expressions are mediated by partially
overlapping neural circuits, including the amygdala. We therefore
hypothesized that facial expression would modulate the effect of
gaze direction on attention. We tested 12 subjects in a task
requiring speeded identification of a peripheral visual target
which was preceded by a face briefly presented centrally at
fixation. The central face had either a neutral or fearful
expression, and gazed either toward the target side, the opposite
side, or straight ahead. Expression and gaze were not relevant to
the task and not predictive of target location or identity.
Nevertheless, gaze direction significantly affected target
identification RTs: faster RTs were observed when the face looked
towards the target side (valid trials), and slower RTs when the
face looked away from the target side (invalid trials). Fearful
expression produced no main effect in RTs but significantly
interacted with gaze direction, resulting in an enhancement of the
gaze effect, both in the valid and invalid trials. These results
show that automatic shifts in spatial attention due to perceived
gaze are modulated by emotional significance of face
expression.
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