Face recognition is not rooted in a universal eye movement information-gathering strategy. Western observers favor a local facial feature sampling strategy, whereas Eastern observers prefer sampling face information from a global, central fixation strategy.Yet, the precise qualitative (the diagnostic) and quantitative (the amount) information underlying these cultural perceptual biases in face recognition remains undetermined.To this end, we monitored the eye movements ofWestern and Eastern observers during a face recognition task, with a novel gaze-contingent technique: the Expanding Spotlight. We used 2° Gaussian apertures centered on the observers' fixations expanding dynamically at a rate of 1° every 25ms at each fixation the longer the fixation duration, the larger the aperture size. Identity-specific face information was only displayed within the Gaussian aperture; outside the aperture, an average face template was displayed to facilitate saccade planning. Thus, the Expanding Spotlight simultaneously maps out the facial information span at each fixation location. Data obtained with the Expanding Spotlight technique confirmed thatWesterners extract more information from the eye region, whereas Easterners extract more information from the nose region. Interestingly, this quantitative differencewas paired with a qualitative disparity. Retinal filters based on spatial-frequency decomposition built from the fixations maps revealed thatWesterners used local high-spatial-frequency information sampling, covering all the features critical for effective face recognition (the eyes and the mouth). In contrast, Easterners achieved a similar result by using global low-spatialfrequency information from those facial features. Our data show that the face system flexibly engages into local or global eye movement strategies across cultures, by relying on distinct facial information span and culturally tuned spatially filtered information. Overall, our findings challenge the view of a unique putative process for face recognition.
Bibliographical noteFunding Information:
This study was supported by the Swiss National Science Foundation (100014_138627).
© 2013 Miellet, Vizioli, He, Zhou and Caldara.
- Expanding spotlight
- Extrafoveal processing
- Eye movements
- Face perception