Back in New York, at the recommendation of Boas, Mead accepted a position as an assistant curator at the Museum of Natural History, where she managed the exhibits on Africa, Malaysia, and the South Pacific. She would work there for 50 years. Mead published Coming of Age in Samoa in 1917, in which she argued that education is a universal experience, and, in its purest form, is the process by which adults show children how to eventually become adults. She explained that the adolescent developmental period for Samoan youth was a time of exploration and discovery rather than a time for learning to adhere to social norms. Mead was preoccupied with sex as a social characteristic and was fascinated with the lack of rigidity for the accepted ways to approach sex that she discovered in Samoa. She concluded that the turbulence and emotional intensity characteristic of adolescent American children was a product of what Americans had decided adolescence was. It was during this period that she divorced Cressman—her latest husband—and married Reo Fortune.

Eugenics dominated American biological, medical, and social theory during this period. Eugenicists, taking their inspiration from the work of Charles Darwin and Gregor Mendel, discoverer of the gene, believed that human beings could improve through selective breeding with the most desirable members of society.