Endogenous Control and Reward-based Mechanisms Shape Infants' Attention Biases to Caregiver Faces.

Infants rely on developing attention skills to identify relevant stimuli in their environments. Although caregivers are socially rewarding and a critical source of information, they are also one of many stimuli that compete for infants' attention. Young infants preferentially hold attention on caregiver faces, but it is unknown whether they also preferentially orient to caregivers and the extent to which these attention biases reflect reward-based attention mechanisms. To address these questions, we measured 4- to 10-month-old infants' (N = 64) frequency of orienting and duration of looking to caregiver and stranger faces within multi-item arrays. We also assessed whether infants' attention to these faces related to individual differences in Surgency, an indirect index of reward sensitivity. Although infants did not show biased attention to caregiver versus stranger faces at the group level, infants were increasingly biased to orient to stranger faces with age and infants with higher Surgency scores showed more robust attention orienting and attention holding biases to caregiver faces. These effects varied based on the selective attention demands of the task, suggesting that infants' attention biases to caregiver faces may reflect both developing attention control skills and reward-based attention mechanisms.