The role of saliency and meaning in oculomotor capture by faces

Long-lasting debates question whether faces are special stimuli treated preferentially by our visual system or whether prioritized processing of faces is simply due to increased salience of their constituting features. To examine this issue, we used a visual search task in which participants had to make a saccade to the circle with a unique color among a set of six circles. Critically, there was a task-irrelevant object located next to each circle. We examined how an upright face, an inverted face or a butterfly, presented near the target or non-target circles affected eye movements to the target. Upright (13.12%) and inverted faces (10.8%) located away from the target circle captured the eyes more than butterflies (8.5%), but upright faces captured the eyes more than inverted faces. Moreover, when faces were next to the target, upright faces, and to some extent inverted faces, facilitated the saccades towards the target. Faces are thus salient and capture attention. More importantly however above and beyond their raw salience based on low-level features, canonical upright faces capture attention stronger than inverted faces. Therefore, faces are ‘special’ and our visual system is tuned to their meaning and not only to low-level features making up a face.