HUMAN FACTORS, 1987,29(1),87-95 Radiation Search and Detection by Ear and by Eye JOSEPH TZELGOV,1 RAFI SREBRO, AVISHAI HENIK, and ABRAHAM KUSHELEVSKY, Ben Gurian University of the Negev, Beer Sheva, Israel Most radiation monitors in use employ visual displays. In some cases the monitor has an auditory display, but even then the operators are usually instructed to rely mainly on the visual infonnation. It is not clear, however, that the visual mode is to be preferred. The present project focuses upon the relative efficiency of various types of information that can be provided by radiation monitors. Two experiments were conducted. In the first, the sub- jects \Vere asked to perform a search task. The second evaluated performance in a detection task. The main independent variable of interest in both experiments was information mode; that is, the mode of providing infonnation about the radiation level. We compared three modes of providing the information: auditory, visual, and redundant (both auditory and visual). It \Vas found that in the detection task the three modes of information resulted in idmticallevels of performance. In the search task, however, the auditory display resulted in a better performance than did either the visual display or the redundant condition. The results are consistent with the concepts of visual dominance and visual bias as suggested by POS11eret al. (1976). The implications of the findings are discussed. INTRODUCTION The increasing use of radioactive materials in industry, medicine, and research has dan- gerous implications due to the possibility of pollution. This danger is increased by the in- ability of the human sensory system to detect radioactive stimulation. Thus, the develop- ment of efficient equipment for radiation de- tection is of critical importance. This project focuses on the relative efficiency of two types of displays for the detection of nuclear radia- tion. Most radiation monitors in use employ vi- sual displays. In some cases the monitor also has an auditory display. However, even in the I Requests for reprints should be sent to Joseph Tzclgov, Dept. of Behavioral Sciences, Ben Gurion University. Beer Sheva, Israel 84105. latter case, the manufacturer's instructions emphasize the use of the visual display. Fur- thermore, the double-display monitor (e.g., the 120BC Berthold model) has no built-in option for utilizing only the auditory display; however, it is possible to employ only the vi- sual display and shut off the auditory signals. In radiation monitoring, when the purpose is to determine the radiation level quantita- tively, a visual-digital display is the only op- tion. However, there are two additional types of monitoring tasks: (l) Detection of radiation. In this case the oper- ator's task is to decide if a prespecified area is polluted by radiation. This task requires one decision; that is, the operator has to decide if a given reading is higher than the reading achieved in a nonradiation situation. Notc that in this task there are almost no memory requirements. © 1987, The Human Factors Society, Inc. All rights reserved.