Covert orienting of attention in 3-month-old infants: The case of biological motion

Humans attend to different positions in the space either by moving their eyes or by moving covertly their attention. The development of covert attention occurs during the first year of life. According to Colombo's model of attention (2001), within the first years there is a significant change in infants’ visuo-spatial orienting mechanisms, from a predominantly overt form to a covert orienting starting from 4 to 5 months of life. The use of non-invasive brain imaging techniques can shed light on the origin of such mechanisms. In particular, EEG and ERP studies can directly investigate the neural correlates of covert attention in young infants. The present study investigated the neural correlates of covert attention employing a visuo-spatial cueing paradigm in 3-month-old infants. Infants were presented with a central point-light walker (PLD) followed by a single peripheral target. The target appeared randomly at a position either congruent or incongruent with the walking direction of the cue. We examined infants’ target-locked P1 component and the saccade latencies toward the peripheral target. Results showed that the P1 component was larger in response to congruent than to incongruent targets and saccade latencies were faster for congruent rather than incongruent trials. Moreover, the facilitation in processing sensory information (priming effects) presented at the cued spatial location occurs even before the onset of the oculomotor response, suggesting that covert attention is present before 4 months of age. Overall, this study highlights how ERPs method could help researchers at investigating the neural basis of attentional mechanisms in infants.