Neural Measures of Social Reward and Information Value in Infants

Infants' limited ability to communicate makes it difficult to know what they are thinking. Researchers often measure babies' visual attention as a way to infer their understanding and interest. However, knowing that infants prefer to look at one display versus another does not necessarily indicate why they prefer it. Some attentional preferences are driven by how much the infant seems to like the stimulus, referred to as its reward value. Other preferences are driven by infants' desire to take in new information and learn more about the world. The goal of the proposed research is to study different patterns in babies' brain activity to determine which of these two reasons, reward value or information value, explains their attentional preferences.

The proposed experiments will use functional near-infrared spectroscopy (fNIRS) to measure hemodynamic responses to neural activity in medial and dorsolateral prefrontal cortex while infants watch and listen to two different speakers. In some experiments, the speakers will differ in how friendly and infant-directed their speech is (i.e., social reward), while in others they will differ in how richly structured the content of their speech is (i.e., information value). All experiments will end by testing to which speaker the infants prefer to attend and/or how much they have learned about the presented speech patterns. These experiments will test the hypotheses that activation in medial prefrontal cortex (MPFC) is associated with social reward value and activation in dorsolateral prefrontal cortex (DLPFC) is associated with information value. Moreover, they will assess the extent to which activation in MPFC and DLPFC during stimulus presentation predict subsequent social preference and statistical learning, respectively. The project will also involve scientific training of students from underrepresented groups and underprivileged backgrounds, and conducting information sessions for new parents about infant brain development.