Inverting faces does not abolish cultural diversity in eye movements

Abstract

Face processing is thought to be invariant across all humans. Since the seminal work of Yarbus (1965), studies of eye movements have consistently revealed systematic, analytical sequences of fixations over the eyes and the mouth during face processing. This triangular scanpath observed in Western Caucasian (WC) observers has long been assumed to represent a universal, biologically-determined information extraction pattern for faces. However, we recently reported a striking cultural contrast. Contrary to intuition, East Asian (EA) observers focused on the central region of faces to extract information holistically during upright face recognition (Jack et al., 2006), questioning the universality of eye movements for faces. It is well established that vertical inversion of objects disrupts natural perceptual strategies and markedly impairs individual face recognition (e.g., Yin, 1969). The comparable lack of experience across cultures with inverted faces represents a unique opportunity to establish the extent to which perceptual cultural strategies are robust and might reveal fine-grained use of diagnostic information. Here we monitored the eye movements of WC and EA observers while they learned and recognized WC and EA inverted faces. Both groups of observers showed a comparable impairment in recognizing inverted faces of both races. In contrast, eye movements revealed differential facial fixation scanpaths. WC showed a scatter inverted triangular scanpath with a bias towards the mouth, whereas EA uniformly extended the focus of their fixations from the center towards one eye. Interestingly, the bias towards the upper part of the face (i.e., mouth) in WC suggests that the extraction of visual information from inverted faces is driven by spatial tuning more than diagnostic information (i.e., eyes). Overall, cultural perceptual differences in eye movements resist the face inversion effect and, critically, reinforce the view that face processing can no longer be considered as arising from a universal series of perceptual events.