Moral licensing!

In the deep recesses of the inner mind is the Great Offset!

We drink Diet Coke -- with Quarter Pounders and fries at McDonald's. We go to the gym -- and ride the elevator to the second floor. We install tankless water heaters -- then take longer showers. We drive SUVs to see Al Gore's speeches on global warming.

These behavioral riddles beg explanation, and social psychologists are offering one in new studies. The academic name for such quizzical behavior is moral licensing. It seems that we have a good/bad balance sheet in our heads that we're probably not even aware of. For many people, doing good makes it easier -- and often more likely -- to do bad. It works in reverse, too: Do bad, then do good.

"We have these internal negotiations going in our heads all day, even if we don't know it," said Benoît Monin, a social psychologist who studies moral licensing at Stanford University. "People's past behavior literally gives them license to do that next thing, which might not be good."

The implications of moral licensing are vast, stretching beyond consumer decisions and into politics and environmental policy. Monin published a study showing that voters given an opportunity to endorse Barack Obama for president were more likely to later favor white people for job openings. Social psychologists point to government standards for fuel efficiency as another example of moral licensing at work: Automakers can sell a certain number of gas guzzlers as long as their overall fleet achieves a specified miles-per-gallon rating.