ABSTRACT
Perrow (1984) provided the following account of what he called a "normal" accident (see Fig. 2.1):
In retrospect, the question is (Perrow, 1984), "Why would a ship in a safe passing situation suddenly turn and be impaled by a cargo ship four times its length?" (p. 217). Based on his analysis of this and other accidents in complex systems, Perrow concluded that the answer lies in the construc tion of a "faulty reality" (i.e., situation awareness; see Sarter & Woods, 1991). In Perrow's (1984) words, "... they [captains, operators, etc.] built perfectly reasonable mental models [italics added] of the world, which work almost all the time, but occasionally turn out to be almost an inversion of what really exist" (p. 230). This is a common theme among researchers of both human error (Reason, 1990) and human power (Klein, 1998) and has in fluenced numerous theories of human decision making (see Lipshitz, 1993). My objective is to extend these theories with a more formal (computa tional) analysis of how (exactly) decision makers construct mental models to achieve situation awareness.
