Developing self-awareness generates perspective conflict: Evidence in the infant brain

Human infants show an early capacity for tracking the attention of others, but older toddlers have trouble ignoring their own perspective when self and other perspectives diverge. Here we test the hypothesis that it is the emergence of self-representation in the second year of life that creates this difficulty because its presence produces a conflict between perspectives which young children cannot yet manage. In this preregistered study, we use functional near infrared spectroscopy (fNIRS) to measure brain activation while 18-month-old infants watch scenarios designed to induce a conflict between self and other perspectives. We found that infants who already pass the mirror self-recognition test, a well-established measure of self-representation, show greater activation in the right prefrontal cortex and inferior frontal gyrus than 18-month-olds who do not yet pass. This data suggests that it is the presence of a self-representation that creates a perspective conflict reflected in enhanced activation of cortical regions implicated in self-perspective inhibition. That infants without a self-representation show less activation in these regions, despite viewing the same perspective conflict scenario, suggests that they do not yet experience the same degree of conflict and may explain why younger infants can track others’ attention while older toddlers have difficulty.