Gesell attended the University of Wisconsin, where he was swept up in the tide of Progressive reform. After completing his Ph.D. at Clark University, he moved to New York City, where he taught elementary school and lived in the East Side Settlement House before launching an academic career. He headed Yale’s Clinic of Child Development, founded in 1911. It was here that Gesell conducted his famous studies of hundreds of New Haven children, from the late 1910s through the 1930s. His project brought children into his Yale laboratory, where they were given mental and behavioral challenges ranging from bells and balls to stairs and strangers. He meticulously recorded their responses in numbers, pictures, and films. Whatever more than half of the children he studied did regularly was defined as “normal.”