Experience-driven perceptual bias in face processing for 8-11 month-old infants

Abstract

Adults inspect the left side (from viewers’ perspective) of others’ face first and for longer time (left gaze bias) and use left side information when face-related perceptual judgments (e.g. similarity, gender, emotion) are requested (left perceptual bias). Infants are reported to exhibit left gaze bias, and we examined whether they possess perceptual bias also. We habituated 19 infants to a real face. During test stage, two faces, each consisted of one half of the habituated face aligned with its own mirror image, hence left–left face (LL face) and right– right face (RR face), were presented side-by-side on the screen. If infants look longer at either face, it indicates that infants find that face more novel, thus implying a perceptual bias. We used Tobii T120 to track infants’ eye movement during both habituation and test stages. We did not find gaze bias during free-viewing habituation or perceptual bias during the test. Instead, we found a right-side bias that our infants looked at faces on the right side of the screen significantly longer than on the left side. Additionally, we observed a tendency that infants’ gazing history during habituation could predict their preference at test stage: those who fixated longer at the left side of a face during habituation were more likely to study longer at the RR faces in test phase and vice versa. This implies a preference of face perception driven by the immediate past experience during infancy, which was never reported before.