Psychophysics and signal detection / by James P. Egan and Frank R. Clarke. Final technical report, Contract no. AF19(628)-266, Report no. ESD-TDR-62-305, 12 November, 1962 for investigation of research concerning auditory detection and recognition of signals by human listeners to Operational Applications Laboratory, Electronic Systems Division, Air Force Systems Command, United States Air Force, Laurence G. Hanscom Field, Bedford, Massachusetts.