Abstract
Under monocular conditions, 40 students observed the reverse of polychrome and monochrome masks and judged them to be concave, convex or flat. The mask was presented upright and illuminated from above, below, right and left and in the upside down position illuminated from below. The magnitude of the perceived depth or relief was estimated using a retractable tape measure. Regardless of color, lighting and orientation, the majority of responses indicated that the hollow masks were perceived to be convex. No significant differences were observed between the depth or convexity of the metric magnitudes and scalar magnitudes of the concave masks in relation to variations in the light source direction, color, and position. The illusory depth, seeing the concave mask as convex, is a robust phenomenon that suggests the predominant role of higher-order processes over the low-order processes in visual face perception.
Highlights
Introduction40 students observed the reverse of polychrome and monochrome masks and judged them to be concave, convex or flat
Under monocular conditions, 40 students observed the reverse of polychrome and monochrome masks and judged them to be concave, convex or flat
The majority of the observers attributed convexity to the concave mask: 75.0% when the concave polychrome mask was illuminated from above, 75.0% when illuminated from below, 72.5% illuminated from the right, 82.5% illuminated from the left, and 80.0% when presented upside down and illuminated from below
Summary
40 students observed the reverse of polychrome and monochrome masks and judged them to be concave, convex or flat. No significant differences were observed between the depth or convexity of the metric magnitudes and scalar magnitudes of the concave masks in relation to variations in the light source direction, color, and position. The illusory depth, seeing the concave mask as convex, is a robust phenomenon that suggests the predominant role of higher-order processes over the low-order processes in visual face perception. The first report of this phenomenon occurred during the observation of cameos by Gmelin in 1744, perceived as alternately concave and convex, through variations in the lighting direction of the objects (Liu & Todd, 2004). To enable the convex perception, a reversal in the direction of the source of illumination occurs The occurrence of this illusion is explained by the use of individual knowledge, cognitive or top-down processes, on faces (Hill & Johnston, 2007)
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call