Detection of vertical elements among oblique ones is enhanced when the former are arranged so as to form a schematic face-like pattern. This face-superiority effect at the detection level indicates top-down/bottom-up interactions between remote visual processing stages. (From Gorea & Julesz (1990). Perception, 19, 5-16.)
Examples of the stimuli used in the experiments. In (a), (b), and (c) target stimuli are embedded among lines oriented at ±45°. These angle differences between target and background elements yielded 100% correct detection performances and were not used in the actual experiments. Stimulus (d), where ‘noise’ elements are oriented at ±14° and ±76°, was used in the experiments. (a) and (d) show the ‘face’ stimulus (middle-right in both cases). Symmetrical and asymmetrical ‘nonface’ stimuli are shown in (b) and (c).