Does nutritional deficiency retard psychological development? The Tulane Nutrition Study reports the first segment of its research based on extensive analysis of psychological and nutritional data gathered predominately on children who attended five, 6-week Head Start programs. Scores on a battery of eight psychological tests and two hematological measures (hematocrits and hemoglobin) provided baseline indices of psychological and nutritional status. Initial statistical tests failed to show differences that could be reliably interpreted as developmental retardation. Further analysis involved a pilot study in which dietary intervention produced an improvement in blood levels for the most deficient subgroup. No generalizations can be made until subsequent analysis (1) resolves issues raised by age, (2) controls for initial lack of equivalence in intervention groups, and (3) examines individual differences in nutrition and behavior profiles. Future research will focus on individual cross-sectional approaches and on follow-up studies involving selected children. (WY)