Two avid sports fans plan to travel 40 miles to see a basketball game. One of them paid for his ticket: the other was on his way to purchase a ticket when he got one free from a friend. A blizzard is announced for the night of the game. Which of the two ticket holders is more likely to brave the blizzard to see the game?
The answer is immediate: we know that the fan who paid for his ticket is more likely to drive. Mental accounting provides the explanation. We assume that both fans set up an account for the game they hoped to see. Missing the game will close the accounts with a negative balance. Regardless of how they came by their ticket, both will be disappointed – but the closing balance is distinctly more negative for the one who bought a ticket and is now out of pocket as well as deprived of the game. Because staying home is worse for this individual, he is more motivated to see the game and therefore more likely to make the attempt to drive into a blizzard.
The emotions that people attach to the state of their mental accounts are not acknowledged in standard economic theory. An Econ would realize that the ticket has already been paid for and cannot be returned. Its cost is “sunk” and the Econ would not care whether he had bought the ticket to the game or got it from a friend (if Econs have friends). To implement this rational behavior, (the fan) would have to be aware of the counterfactual possibility. “Would I still drive into this snowstorm if I had gotten the ticket free from a friend?” It takes an active disciplined mind to raise such a difficult question.
Thinking, Fast and Slow, Daniel Kahneman