A first cooperative research program in developmental psychology was established in the Clark questionnaire studies. The program was not meant to be free-standing but to elaborate an evolutionary conception of child development synthesized from findings of several scientific fields. The short-lived program had some serious faults, but an examination of its research papers suggests that it produced some worthwhile work. The child-study researchers gathered information about children's social and emotional reactions in everyday settings; one or two of their studies were replicated; they found pattern and order; they elaborated a meaningful social-biological view of child development.