I must not have an economist brain, because I cannot persuade myself that the sunk cost fallacy is truly fallacious.
You know about this already, right-- that it's supposedly bad judgment to say "I should go to the gym because I paid for the membership"? You should go to the gym because it makes sense to go to the gym. The money is already gone, whether or not you go to the gym.
I find this allegedly fallacious logic SO MOTIVATING.
Right now, though, it is tripping me up. I've known all year -- literally since I wrote my new year's resolution post in January -- that I wanted to do a fall half-marathon and also that it would be pretty tough to fit it in. I am slow enough that half-marathon training eats a lot of time, and as the distances increase they also burn a lot of willpower. I signed up for an October half-marathon KNOWING that it would be tough to get the runs in around the fall retreat schedule and also tough to get to the race itself, since I will get home from Arizona at about 11pm the night before the race. Which is 45 minutes away.
Last Saturday during my 10-miler I thought, "I can't keep this up for another month. But! I could email a pal to see if she is willing to help build a marathon relay team instead! I can switch my registration around even though I can't get a refund. That could work!" I can do a quarter of a marathon, no problem.
The relay idea doesn't seem to be working out, though. Under the circumstances the strictly logical decision would be to keep exercising for the stress relief and endorphins while acknowledging that I'm going to skip the half-marathon I registered for. It was good to have a goal that kept me running; it's probably more sensible to adjust the goal than to insist on powering through to meet it.
But I paid for the race. I should run the race, says the voice in my head. Don't be a quitter, says the voice in my head.
The first time I read about the sunk cost fallacy I thought, "That is the dumbest thing I ever heard. OF COURSE you should go to the gym if you paid for the gym membership." These days I no longer think it's the single dumbest thing I ever heard. But I'm pretty sure I'll never think like an economist.