Emotional Faces Modulate Spatial Neglect: Evidence from Line Bisection

One patient with left spatial neglect (FM) and four right-brain damaged controls without neglect were tested on a line bisection task with pictures of neutral and emotional faces of the same size as unilateral cues. Our aim was to investigate whether bisection biases induced by cuing can be better explained as the result of a direct perceptual lengthening of the cued part of the line or, alternatively, because cues draw spatial attention thereby increasing the salience of that side. We thus manipulated the attentional salience of the cues (higher for emotional faces and lower for neutral faces) while keeping physical dimensions and perceptual characteristics of the stimuli constant. Our findings showed that left emotional faces were more effective than left neutral faces in reducing bisection errors in patient FM. These data indicate that in the left neglected hemispace cues bias attention rather than simply altering the perceptual point of balance of the line in the horizontal plane.