Meanwhile, the right hemisphere of the adult brain is largely responsible for interpreting human social-emotional cues, and it receives those signals dominantly through the left eye. So the mother’s left eye carefully watches the infant’s face, interpreting the baby’s emotional state, while the infant gazes intently up at the most expressive side of the mother’s face, learning how to read her emotions and respond—something that human beings spend huge portions of their childhoods learning how to do.
