ABSTRACT

Optimizing the performance of a man-machine system requires that the system enable the decision-maker to make effective decisions. Even in technologically advanced systems designed to minimize the impact of human error on the system, errors by the decision-maker can have serious repercussions. For example, one study found that 80-85% of aviation accidents are attributed to human error. Of these errors, failures in decision-making were a causal factor in approximately 52% of all fatal accidents and 35% of nonfatal accidents (Jensen 1982) Interestingly, many of the errors that are defined as errors in decision-making did not actually occur at the decision point (i.e. action selection). Instead many errors occurred during the time in which the decision-maker was developing an understanding of the current environment, a necessary precursor to the actual decision point. The decision-maker’s understanding of the situation is known as their situation awareness (SA). Situation awareness is defined as “the perception of the elements within a volume of time and space, the comprehensions of their meaning, and the projection of their status in the near future” (Endsley 1995a). Endsley (1995b) found that 88% of aircraft accidents associated with human error could be attributed to errors in situation awareness rather than errors in action selection.