Content Warning: The Nurture Assumption mentions physical and verbal abuse, postpartum depression, and concentration camps in exploring human development through traumatic experiences.

Steven Pinker, a psycholinguist and professor at Harvard, recalls first reading Judith Rich Harris’s “group socialization theory” in “Psychological Review” magazine. While he was surprised by her claims, he was soon persuaded, as he felt her theory addressed some observations which he and other scholars were unable to explain. For example, children speak like their peers, not their parents, and children of immigrant parents acquire language fluency even if their parents never do. Pinker expresses dissatisfaction with the “standard social science model,” which considers parents the primary influence in child development (xxiv). He refutes this model by framing children as individuals with their own biological interests in forming relationships, as joining a group maximizes one’s chance of survival and finding a mate. He lauds Harris for questioning the “attachment hypothesis,” which claims children’s attachment to their mothers informs all later attachments. Pinker calls her work “electrifying” and claims it may be a critical moment in understanding human psychology (xxv).