Another reason for honoring the sunk cost of the movie ticket (related to avoiding regret) is that you know yourself well enough to realize you often make mistakes. There are many irrational reasons why you would not want to see the movie after all. Maybe you’re unwilling to get up and go to the movie because you feel a little tired after eating too much. Maybe a friend who has already seen the movie discourages you to go, even though you know your tastes in movies don’t always match. Maybe you’re a little depressed and distracted by work/relationship/whatever problems. Etc.
For whatever reason, your past self chose to buy the ticket, and your present self does not want to see the movie. Your present self has more information. But this extra information is of dubious quality, and is not always relevant to the decision. But it still influences your state of mind, and you know that.
How do you know which self is right? You don’t, until after you’ve seen the movie. The marginal costs, in terms of mental discomfort, of seeing the movie and not liking it, are usually smaller than the marginal benefit of staying home and thinking about what a great movie it could have been.
The reasoning behind this trivial example can easily be adapted to sunk cost choices in situations that do matter.
The sunk cost fallacy is easy to understand and to point out to others, but I caution against using it too often. The point of the fallacy is to show that only future costs and benefits matter when making a decision. This is true, but in reality those costs and benefits (and especially their probabilities) are hard to define. It is not clear whether the extra information that was received after ‘sinking’ the cost has an impact on the cost and benefit probabilities.
You also know that, in any case, if the decision to sink the cost in the first place was the right one after all, the decision to continue is even more rational as a large part of the cost has already been spent. You can go see a movie for free that other people still have to pay for.
Another reason for honoring the sunk cost of the movie ticket (related to avoiding regret) is that you know yourself well enough to realize you often make mistakes. There are many irrational reasons why you would not want to see the movie after all. Maybe you’re unwilling to get up and go to the movie because you feel a little tired after eating too much. Maybe a friend who has already seen the movie discourages you to go, even though you know your tastes in movies don’t always match. Maybe you’re a little depressed and distracted by work/relationship/whatever problems. Etc.
For whatever reason, your past self chose to buy the ticket, and your present self does not want to see the movie. Your present self has more information. But this extra information is of dubious quality, and is not always relevant to the decision. But it still influences your state of mind, and you know that. How do you know which self is right? You don’t, until after you’ve seen the movie. The marginal costs, in terms of mental discomfort, of seeing the movie and not liking it, are usually smaller than the marginal benefit of staying home and thinking about what a great movie it could have been.
The reasoning behind this trivial example can easily be adapted to sunk cost choices in situations that do matter.
The sunk cost fallacy is easy to understand and to point out to others, but I caution against using it too often. The point of the fallacy is to show that only future costs and benefits matter when making a decision. This is true, but in reality those costs and benefits (and especially their probabilities) are hard to define. It is not clear whether the extra information that was received after ‘sinking’ the cost has an impact on the cost and benefit probabilities. You also know that, in any case, if the decision to sink the cost in the first place was the right one after all, the decision to continue is even more rational as a large part of the cost has already been spent. You can go see a movie for free that other people still have to pay for.