One of the main limits on willpower, though, turns out to be…willpower. Exerting self-control in one domain makes it harder to exert self-control in another, at least right away.

Thus reads a line from the article “Resisting Temptation” in The Observer (the magazine put out by the Association of Psychological Science). The piece summarizes some of the most interesting research in psychology. Another excerpt:

In a study led by APS Fellow Roy Baumeister (Florida State University), a group of hungry participants was forbidden from eating freshly baked cookies sitting on a plate in front of them and made to eat radishes instead. These paticipants gave up faster on a subsequent frustrating task than did a control group who had been freely allowed to indulge their sweet tooth (Baumeister, Bratslavsky, Muraven, & Tice, 1998). And in a study led by Mark Muraven (SUNY-Albany), participants made to suppress all thoughts of a white bear for five minutes consumed more beer afterwards in a “taste test” than did those in a control group, even though they knew they would subsequently be taking a driving test (Muraaven, Collins, & Nienhaus, 2002).

Numerous variants of this paradigm — making a group of participants exercise restraint in one situation and then comparing their performance with that of a control group in a subsequent self-control task — have shown the same pattern: Self-control is a limited resource that can be drained through exertion (Baumeister, Vohs, & Tice, 2007). Baumeister and colleagues call this fatigued state “ego-depletion,” and it is a significant discovery because it explains why many of our specific willpower failures occur when our strength has been taxed by other self-control demands. Refraining from blowing-up at one’s boss during the day may make it hard to resist a big meal of comfort food that evening. The constant effort of sticking to a diet may cause us to make more impulsive purchases at the mall.

The muscle that controls willpower does much more than just keep our impulses in check. It is part of a larger set of executive functions involved in self-monitoring, coping with stressors, weighing alternatives, and making decisions, all of which draw on the same energy source.

It is even possible to become ego-depleted by watching other people exert willpower…Exercising vicarious self-control led people to be willing to spend more on the consumer goods, as compared with a control group (Ackerman, Goldstein, Shapiro, & Bargh, in press).

A couple of weeks ago JAZ posted on Malcolm Gladwell’s take on America’s ‘rugged idealism’ – the American Dream required a sense of self-sufficiency, self-reliance, and self-control. But does it really work? My take (and you may disagree) on this is that the more we try to control ourselves and do the right thing (i.e., following the Law), the more we fail at subsequent attempts to control ourselves (i.e., transgressions are not decreased). In fact, the harder we try to exert self control, the more we will fail because of ego-depletion – we only have so much (or so little!) of willpower to begin with! It seems to ring true with Paul’s words: “Where there is no law there is no transgression” (Romans 4:15) – where you don’t have to exercise self control (no ego-depletion), there is no subsequent failure in exercising self control!