But part of their success reflects grit over the closing stretch. Most marathoners run the final 2.195 kilometers (1 mile, 640 yards) about 8 to 10 percent slower than they run the preceding distance. The clear exception is those who need to stay on pace to meet their goal; they push themselves harder and slow much less toward the end.

The broader implications of all this come from realizing that the cost-benefit trade-off that marathoners face is remarkably similar to what we all face when trying to decide how hard to work, how hard to study and how to invest.

In the usual analysis, economists suggest it’s worth putting in effort as long as the marginal benefit from doing so exceeds the corresponding marginal cost of that effort. The fact that so many people think it worth the effort to run a 2:59 or 3:59 marathon rather than a 3:01 or 4:01 suggests that achieving goals brings a psychological benefit, and that missing them yields the costly sting of failure.

But in other domains, this discontinuity between meeting a goal and being forced to confront a loss can lead to bad economic decisions. Because losses are psychologically painful, we sometimes strain too hard to avoid them.

For instance, when you sell your house, your goal may be to get at least what you paid for it. But this simple goal has led to disastrous decisions for those who bought homes in Florida or Nevada during the housing bubble. Too many homeowners set their selling prices with an eye on recouping past investments rather than on current market conditions, and as a result, their homes didn’t sell, deepening their financial distress.

A similar unwillingness to recognize losses in our stock portfolios has led many investors to hold onto their losing stocks too long, even if this requires selling out of their winning stocks too early.

The pain of a loss looms so large in the labor market that few workers are willing to accept even a small pay cut, even if that’s what is necessary to keep their jobs. Just as the distribution of marathon times shows a big spike at 3:59, the distribution of wage changes has a big spike at 0 percent change.