Effects of high visual taskload on the behaviours involved in complex monitoring

Abstract

A simulated air traffic control task was used to study the effects of prolonged monitoring on some of the behaviours (complex discriminations, interpretations, decisions, memory for actions taken) frequently associated with operational monitoring tasks, but seldom examined in laboratory vigilance studies. Forty-eight subjects performed the monitoring task under relatively high taskload conditions for 2h. Two types of critical events were employed. Simple events consisted of a readily detectible alphanumeric change; complex events (detection of two aircraft at the same altitude on the same flight path) required considerable information processing for detection. Behaviours following detection of each type of event enabled acquisition of data on short-term memory, decision time and errors, procedural errors, and motor movement time. Time to detect aircraft at the same altitude was found to increase significantly over the 2 h as did failures to detect these events; detection time for the simpler type of event showed no evidence of impairment, nor was any impairment found for any of the other task behaviours that were measured. The results are discussed with reference to previous studies which suggest that the extent to which attentional decline impairs complex monitoring performance may be related to the amount of information processing required for event detection.