Arguably one of the most important elements of parenting is modeling and teaching empathy, which is the focus of the final chapter. Siegel and Bryson argue that the brain is a social organ, designed to interact with other brains. They explain the discovery and function of mirror neurons—the neurons that fire in response to seeing an action that a person has performed before or understands in some way. 

Mirror neurons were discovered in brain scans performed on monkeys in the 1990s. When a monkey ate a peanut, neurons fired, but surprisingly, when the monkey saw a person eat a peanut, the same neurons fired. The belief surrounding mirror neurons is that they help people empathize with others, in part by sharing emotional and physical experiences. Recalling neuroplasticity, Siegel and Bryson point out that when a meaningful experience is shared, the brain is permanently altered, creating more groundwork for interpersonal connection.

The existence and function of these mirror neurons suggest that attachments and experiences of relationships in early life literally provide the foundation for expectations of interpersonal relationships later on. Siegel and Bryson describe a healthy attachment between parent and infant, then contrast it with an infant who must disconnect from neglectful parents to survive.