Early in an infant's life, what are the first two facial expressions to emerge that have clear communicative functions?

Question

Quizplus · Accepted Answer

The first two facial expressions to emerge that have clear communicative functions are distress and smiles. Distress signals discomfort or pain, while smiles signal contentment and pleasure. These expressions are thought to be innate and are present from early in an infant's life. Fear and love are emotions that emerge later in infancy and childhood. Approach and avoidance behaviors are not facial expressions but rather physical movements.

Early in an Infant's Life, What Are the First Two