SUMMARY/ABSTRACT Caregivers are both socially rewarding and a crucial source of learning input, and infants’ ability to prioritize attention to their caregiver over other competing stimuli is critical for effective early learning. Altered processing of social reward is common across several atypical developmental contexts, including among infants of depressed mothers and children diagnosed with autism spectrum disorders (ASD). This reduced sensitivity to social reward may disrupt infants’ attention to caregivers and contribute to poorer learning outcomes associated with maternal depression and ASD. To understand how attention mechanisms become disrupted in atypical development it is necessary to characterize their normative development. Two distinct attention mechanisms, attention orienting (shifting attention to select information) and attention holding (maintaining attention to process information), function together to shape early learning. However, past research linking caregiving experiences (i.e., social-motivational factors) to developing attention has only examined infants’ attention holding biases to caregivers without also examining orienting. Adults show robust orienting biases to motivationally salient stimuli, but research investigating early attention orienting has not addressed social-motivational factors and instead emphasizes mechanisms based on perceptual salience and endogenous control. As a result, the role of social- motivational factors in the typical development of infants’ attention orienting is unknown. The proposed research will investigate the development and predictors of infants’ attention biases to caregivers and strangers who engage in salient caregiving behaviors. Study 1 will use eye tracking to longitudinally characterize within-subject changes in attention orienting and holding biases to caregiver vs. stranger faces from 4- to 8-months of age (Aim 1). We will use additional measures of focused attention and behavioral coding of infant-caregiver interactions to determine the extent to which caregiving quality and endogenous attention control predict these changes in attention biases over time (Aim 2). Study 2 will determine the extent to which caregiving behaviors drive infants’ attention beyond the familiarity of the social partner (Aim 3). Across four experiments, we will assess whether infants’ preferential orienting generalizes to strangers who engage in caregiver-typical behaviors (i.e., appearing frequently, using infant-directed speech, responding contingently to their behavior). Research has extensively documented that early infant-caregiver interactions are critically important for social-emotional development, but we know far less about how these experiences influence developing cognitive skills. By characterizing the development of infants’ attention biases to caregivers and identifying predictors of individual variance in these biases, this work will ultimately promote our understanding of mechanisms that link social reward processing to infants’ early attention to and learning from caregivers in typical and atypical development.

PROJECT NARRATIVE Infants of depressed mothers and children diagnosed with autism spectrum disorders show reduced sensitivity to social reward, which may disrupt their ability to prioritize attention to and learning from their caregivers. However, past research examining infants’ attention orienting has emphasized mechanisms based on perceptual salience and endogenous control without addressing the role of social-motivational factors (e.g., caregiving quality). The proposed research investigates the extent to which social-motivational factors and endogenous attention control predict attention orienting to caregivers in infancy, with a long-term goal of understanding mechanisms that link social reward processing to early attention in both typical and atypical development.