In the field of Behavioral Economics, researchers study how psychological, emotional, and social factors influence economic decisions. Perhaps, in the end, it’s not that surprising to learn that our decisions aren’t the pure product of rational economic calculations only, but are influenced by behavioral patterns and instincts that have evolved over our entire history as a species. The field has yielded some surprising, counter-intuitive insights into how our “emotional” brain can override our supposed rational brain, reflecting what are perhaps hard-wired assumptions about the way we experience the world.

You might be wondering what any of this has to with running, but bear with me for a little longer.

A few years ago, Uma Karmarkar, an assistant professor of marketing at Harvard Business School, and Bryan Bollinger, of Duke’s Fuqua School of Business, studied the grocery bills of thousands of California shoppers. One of their findings, since replicated with other data, concerned what they called the “licensing effect.” In brief, consumers who brought reusable bags to the store — an act of virtue — were more likely to buy organic foods, but were also more likely to buy foods like ice cream, chips, candy bars, and cookies. After ruling out other possible reasons for this effect, Karmarkar and Bollinger concluded that consumers who brought reusable bags were giving themselves license to indulge in junk food as a reward for their self-acknowledged good behavior. (“Reusable Bags Make People Buy Organic—and Junk“)

Other researchers have found examples of this effect in other areas. For example, one 2009 study observed that, after buying “environmentally friendly” products, consumers were more likely to cheat at a simple counting exercise (Do Green Products Make Us Better People?). The licensing effect, which I am going to re-christen the “virtue trap,” seems to suggest that when we do good, and are aware of ourselves doing good, we give ourselves permission to bend other rules.

While it’s entertaining to poke fun at the hypocrisy of others who think of themselves as virtuous, the point is that we’re all vulnerable to this trap. I also think it’s a trap that we runners fall into all the time.

For example, in what bizarre scenario would it be virtuous, or even respectable, to consume several alcoholic beverages before noon on a Sunday morning? And yet, on almost any weekend, you’ll see runners doing exactly that after knocking out a hard five miles in a Pub race. Somehow, it feels completely normal to indulge after the self-discipline of racing all-out for a half hour.

Similarly, we earn the right to lie on the couch watching football all afternoon, by getting up early and plodding through an exceedingly sweaty and therefore virtuous long run. Oh sure, we ought to be doing chores around the house, or calling our moms, but we really deserve a little relaxation after that profound effort.

Has anyone ever noticed how much junk food is distributed after road races? Would we eat that stuff if we hadn’t just raced? I don’t think so, or at least I think we’d show a little more restraint. But again, our appetites aren’t in any mood for restraint, and they overwhelm our more responsible selves. “Hey, don’t hassle me, man! I just raced, and by the way, did you see me kick that last 400 meters?”

I know that the virtue trap affects me in other, more subtle ways, too. I know, rationally, that the harder my workout, the more I ought to stretch and use the foam roller to help with my recovery. But the harder I’ve run, the more likely I am to “give myself a break,” from the tedious rehab work that the hard run requires. And that goes for all the other things that I do besides running. Clean out the shed? I just ran 12 miles! Put down all the storm windows? I just did a hard tempo run! Etc.

Krumarkar and Bollinger did speculate that the licensing effect diminishes as a behavior comes to be seen as expected, rather than conspicuously virtuous. Eventually, instead of a self-praising for bringing a reusable bag to the grocery store, we kick ourselves (and endure the shaming of others) when we forget, and have to accept plastic bags at the check-out line.

So maybe the trick for runners to avoid the virtue trap is to see a hard effort not as an inherently selfless act of goodness, but as the indulgence we know, in our hearts, it really is.

Avoiding the trap is one more reason we should always remember that running is an incredible privilege. If anything, we ought to be MORE willing to return to our responsibilities and obligations after treating ourselves to a race or workout.