Head and eye movements affect object processing in 4-month-old infants more than an artificial orientation cue

This study investigates the effects of attention-guiding stimuli on 4-month-old infants' object processing. In the human head condition, infants saw a person turning her head and eye gaze towards or away from objects. When presented with the objects again, infants showed increased attention in terms of longer looking time measured by eye tracking and an increased Nc amplitude measured by event-related potentials (ERP) for the previously uncued objects versus the cued objects. This suggests that the uncued objects were previously processed less effectively and appeared more novel to the infants. In a second condition, a car instead of a human head turned towards or away from objects. Eye-tracking results did not reveal any significant difference in infants' looking time. ERPs indicated only a marginally significant effect in late slow-wave activity associated with memory encoding for the uncued objects. We conclude that human head orientation and gaze direction affect infants' object-directed attention, whereas movement and orientation of a car have only limited influence on infants' object processing.