Effects of eye gaze cues provided by the caregiver compared to a stranger on infants' object processing.

Previous research has shown that eye gaze affects infants' processing of novel objects. In the current study we address the question whether presenting a highly familiar face vs. a stranger enhances the effects of gaze cues on object processing in 4-month-olds. Infants were presented pictures of the infant's caregiver and another infant's caregiver (stranger) either turning eye gaze toward an object next to the face or looking away from the object. Then objects were presented again without the face and event-related potentials (ERP) were recorded. An enhanced positive slow wave (PSW) was found for objects that were not cued by the caregiver's eye gaze, indicating that these objects required increased encoding compared to objects that were cued by the caregiver's gaze. When a stranger was presented, a PSW was observed in response to objects regardless of whether the objects were gaze-cued or not. Thus, the caregiver's eye gaze had a larger effect on infants' object processing than the stranger's gaze. This suggests that at 4 months of age the caregiver's eye gaze is easier to process for infants, more salient, or both. The findings are discussed in terms of early social cognitive development and face processing models.