Abstract
A critical component of face detection is the processing of the configural aspects of the face, namely, the spatial positioning of facial components with respect to each other. This is in contrast with the featural aspects of a face, namely, the local properties, such as eye shape, nose shape, etc. Perceptually, low spatial frequencies play a large role in configural processing, whereas high spatial frequencies play a large role in featural processing (Goffaux et al, 2005). In this study, our goal was to determine whether the type of face difference, configural or featural, affects facial discrimination extrafoveally. Subjects were presented a face at fixation for 1500 ms, then, after a 200 ms high-contrast noise mask, were presented a second face at a location of varying eccentricity to the left or right of the original face for another 1500 ms. Subjects were cued to the location of the second face from the start of the trial until the presentation of the second face with a high-contrast noise pattern indicating where the face would be located. In 50% of the trials, the two faces were the same, and in the other 50%, the faces differed by a configural difference (spacing between eyes or distance from nose to mouth) or a featural difference (eye shape or nose shape). Subjects were asked to respond via button press if the second face differed from the first face without moving their eyes from a centrally presented fixation cross. We found above chance detection of configural face differences in the parafovea, whereas we did not find significant detection of featural differences outside of central vision. Our results show that configural face differences can be used to discriminate faces extrafoveally.