Human detection efficiency performance deteriorates rapidly in a wide variety of monotonous monitoring tasks (Stroh, 1971). The upsurge of interest in research on human performance vigilance began during World War I1 (Baker, 1962). Investigations of human performance decrements were centered about ships' lookouts and radar operators. The interest in vigilance research continues because many of today's military, industrial and transportation systems still embody these features (Adams, 1965; Mackie, 1977). Rapidly developing electronics capability over the past several years has resulted in a dramatic increase in the fidelity of simulated vigilance task apparams with an exponential rise in costs. Beatty, Greenburg, Deibler, and O'HanIon (1974) employed a radar simulator comparable to actual equipment in their study of theta brain wave rhythms and radar monitoring efficiency. While such high fidelity and high'cost apparatus might be justified for large-scale grant-supported projects, there is virtually no research evidence that such fidelity contributes to the validity of experimental outcomes. Finnegan, Kelly, and Trollip ( 1977) noted that the great strides in simulation have often been guided more by what is technologically feasible than by what is economically and practically desirable. Making a system more realistic in appearance does not necessarily make it any better for assessment of human performance factors. The cost of high fidelity equipment has, however, meant that few university psychology departments have been able to support smaller scale vigilance experiments in teaching or research. The system described in this paper was designed to minimize costs and maximize simplicity by employing apparatus commonly available in most psychology or human performance laboratories. It was decided that a minimum system should be capable of providing (1) vigilance task stirn,uli, ( 2 ) variable background clutter, ( 3 ) monotonous conditions, and (4) a permanent recording of stimuli as well as subjects' detection responses.