Emergency signal failure: implications and recommendations

As automation becomes more prevalent in complex task systems, operators are confronted with a myriad of emergency signals. Although much research has been performed to improve the structure and function of signalling systems, it has concerned mainly those stimuli that are presumed to accurately indicate danger. The current report discusses the general area of emergency signal failure, its implications for complex task performance, and recommendations for design and research. A general description of the problem is followed by a review of the applicability of scientific theory to human behaviour during and following signal failure, and the authors conclude with recommendations for personnel training and warning signal design and research.