Thomas Marill."October 30, 1956." "This report is based on a thesis submitted to the Department of Economics and Social Science, M.I.T., in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Psychology, June 1956."Bibliography: p. 73.Army Signal Corps Contract DA36-039-sc-64637 Dept. of the Army Task No. 3-99-06-108 Project No. 3-99-00-100