FAA Office of Aerospace Medicine
Civil Aerospace Medical Institute
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AVIATION MEDICINE REPORTS

Report No: DOT/FAA/AM-90/3

Title and Subtitle: Effects of Monitoring Under High and Low Taskload on Detection of Flashing and Colored Radar Targets

Report Date: January 1990

Authors: Thackray, R.I. and Touchstone, R.M.

Abstract: While midair collisions between aircraft are extremely rare occurrences, "near midair" incidents are more common. The present study sought to evaluate the gains in conspicuity that might be realized if flashing or color were added as redundant cues to indicate the presence of unexpected, nontracked aircraft entering controlled airspace and to examine the extent to which increased taskload and fatigue might influence the expected gains. Sixty-four subjects monitored a simulated air traffic control task over a 2-hour period for possible conflict situations (their primary task) under either high or low primary taskload conditions. They also monitored for occasional intrusions by light aircraft identifiable on the basis of target shape alone or with color and/or flashing added as redundant cues. Flashing as a redundant cue was found to be superior to color in all aspects tested; unlike color, detection of flashing targets was unaffected by screen location and by changes in primary taskload. Flashing was also least affected by monitoring fatigue. It was concluded that the superiority of flashing over color in attracting attention to objects in a display must be weighed against its possible potential for distraction. A practical means of accomplishing this in operational situations is through the use of touch sensitive displays to both acknowledge/confirm target location and to deactivate flashing.

Key Words: Air traffic control, attention, color, flashing, monitoring, performance, vigilance, warning signals

No. of Pages: 17