Interpersonal Neurobiology (IPNB) is primarily a theory and practical working model which describes human development and functioning as being a product of the relationship between the body, mind and relationships. Another term for it is relational neuroscience. IPNB describes how the brain and mind are shaped, or developed, and how they function based on the interplay of genes in the context of relationships. IPNB is heavily rooted in attachment theory.