Abstract
The eyes are known to attract attention. Visual exploration of faces is primarily centered on these internal features. The present study investigated the impact of altering the face configuration on face visual exploration, by removing the eyes and presenting faces upside-down.
Young adults (n=16) were presented with a series of face photographs, displayed for 4 seconds, once in each of four blocks. Faces were presented upright or inverted, with or without eyes. Participants were told to study each face for a later test, to ensure they attended to the 'stimuli, but no test was given. Eye movements were monitored throughout the task.
The average number of fixations made to a face did not differ as a function of orientation (upright vs. inverted) but markedly decreased for stimuli without eyes. Decreases in the number of fixations were observed across blocks for all stimulus conditions. However, the proportion of fixations that were allocated across different face features did not change across blocks. Thus learning and development of stored face representations were reflected in a decrease of fixations with no change in the visual exploration pattern.
In contrast, the proportion of fixations allocated across face features varied with both inversion and presence of the eyes. More fixations were directed to the right versus the left eye area for inverted compared to upright faces. This effect could reflect a larger engagement of the left hemisphere with inversion. For the no-eye conditions, more fixations were directed to the nose region while fewer were directed to the eyes. However, although no eyes were present, 15% of the fixations were still directed to the eye regions. This surprising finding suggests visual exploration is largely based on subjects' expectations and face representations in memory rather than being solely driven by bottom-up stimulus features during perception.
This study was supported by funding from the Canadian Institutes for Health Research (CIHR) and the Canada Research Chairs Program.