One factor is the lore of traders, in which perhaps the most common maxim "run your profits and cut your losses" (Fenton-O'Creevy Nicholson, Soane, and Willman 2005, p. 192) directly contradicts the predisposition posited by prospect theory. The maxim enjoins traders to continue to hold risky positions when in the domain of gains and to liquidate those in the domain of losses. The need for the maxim suggests that prospect theory's diagnosis of the typical predisposition is correct, but if the maxim is influential it will counter the predisposition. A second factor again may provide both evidence of the predisposition and a mechanism countering it: the role of traders' managers, part of whose job is often to discourage undue risk aversion while also detecting and stopping the dangerous "doubling up" of loss-bearing trades (Fenton- O'Creevy, Nicholson, Soane, and Willman 2005).

Donald MacKenzie, An Engine, Not a Camera, loc. 1202