Situation Awareness: Is the glass half empty or half full?

Situation awareness is certainly one of the important constructs for human factors practitioners especially human engineers. Indeed, it gives keys to allow breaking the dilemma of the human-machine system designer between the two opposite human roles in systems: a negative role as they may make errors and a positive role in that they are able to detect and recover their own errors as well as process malfunctions. We might have expected that the age of this concept would allow it to be rather mature and refined enough for efficient use. Instead, as practitioners discover its usefulness, it becomes more and more subject to controversy. Nevertheless, the construct has become popular enough to be used in everyday life, for instance in a legal dispute. Therefore, it can be caricatured with the metaphor: the half empty glass or the half full glass. This paper first recalls several strengths and weaknesses of the SA constructs: the usefulness of the concept, the numerous concurrent definitions despite the clarity of Endley's one, the lack of measurement methods associated with some of these definitions, the lack of organisational foundations for collective SA and therefore the lack of method for designing collective SA. As an answer to the last point, this paper proposes the framework of cooperation between agents and its similitude with collective SA. Finally, on the basis of several examples, it gives indications for designing collective SA through the concept of common workspace, a construct shared with the cooperation framework.