The bygones principle does not always accord with real-world behavior. Sunk costs do, in fact, often influence people's decisions,
[8][15] with people believing that investments (i.e., sunk costs) justify further expenditures.
[17] People demonstrate "a greater tendency to continue an endeavor once an investment in money, effort, or time has been made."
[18][19] This is the
sunk cost fallacy, and such behavior may be described as "throwing good money after bad",
[20][15] while refusing to succumb to what may be described as "cutting one's losses".
[15] For example, some people remain in failing relationships because they “have already invested too much to leave.” Still others are swayed by arguments that a war must continue because lives will have been sacrificed in vain unless victory is achieved. Likewise, individuals caught up in psychic scams will continue investing time, money and emotional energy into the project, despite doubts or suspicions that something is not right.[21] These types of behaviour do not seem to accord with rational choice theory and are often classified as behavioural errors.[22]
