How much self-control do you really have?
At this time of year many of us kick back, anticipating that we will reassert self-control in January with New Year’s resolutions. In November, you may have read the post “It’s the season of eating, should we be concerned?” which discussed binge eating. It made me think about the process of making healthy decisions at a time of year when we are typically more focused on celebrating and vacation. Combined with how much willpower it took for me to put down the Hunger Games to write this post – it is winter break after all—it felt only fitting to address the topic of self-control and how much we really have. Much research has supported the idea that willpower (the ability to exercise self-control) is a limited resource, and the more you exert self-control on one task the less you have left for another decision. This phenomenon is often referred to as “ego depletion” and follows from the theory that self-control is a resource that can be exhausted and replenished. For example, I have to use a lot of self-restraint to make myself study for finals, so I have trouble also keeping out of my candy stash while studying. I assume that once I’ve finished finals and get to relax it will be easier to cut back on the sweets. The broader “strength model of self-control" indicates that self-control is like a muscle that can get tired but can also be strengthened. As my candy-studying example indicates, I’m all too familiar with and pretty quick to accept this theory (I take solace in the fact that at least I’ve built up enough self-control to actually study).
However, in 2010 a set of studies by Veronika Job, Carol Dweck and Gregory Walton challenged this limited resource theory. They found that people’s beliefs about willpower determine whether they experience ego depletion or not. Many people think that willpower is a limited resource; yet, others believe that willpower is not limited and can actually be activated and potentially bolstered by engaging in a difficult task that requires self-control. One study looked at people who naturally fell into these two camps of believing willpower was a limited versus nonlimited resource. After completing an initial task that has been shown to deplete self-control, only the participants who believed that willpower was a limited resource actually preformed worse on a subsequent task requiring self-control (compared to others who did not do a depleting first task).
From this first study alone, it would be possible that there were just differences between people who automatically believe in limited or nonlimited self-control, so the researchers also manipulated participants’ willpower beliefs in a second study. Half of the participants were randomly assigned to read statements supporting the limited resource theory while the other half read ones supporting the nonlimited resource theory; reading the statements led participants to agree with the theory that was endorsed. Again, the researchers basically found a self-fulfilling prophecy; only those participants who believed the limited resource theory showed worse performance on the second self-control task after completing the depleting task. An additional study showed that all participants who completed the initial self-control depleting task felt equally exhausted, but only the participants who believed the limited resource theory had this exhaustion negatively impact their subsequent performance on an additional task requiring self-control.
Their final study actually followed students with these different willpower beliefs in real life, studying their behaviors at different times of year: for example, how much unhealthy food they ate and how much they procrastinated during finals week. And indeed, the participants who believed in the nonlimited resource theory ate less junk food and procrastinated less than those who thought self-control was limited.
Basically, though the researchers acknowledge that there may be biological mechanisms that still support the limited resource theory (e.g. research suggests that glucose may help us exert self control), they provide compelling evidence that willpower may at least not be as limited as many of us think! Clearly I still have trouble breaking my limited resource mindset (probably because I’m looking for any excuse to eat candy), but it would probably be in my best interest to keep in mind that I may have more self-control than I think.
Job, V., Dweck, C. S., & Walton, G. M. (2010). "Ego Depletion--Is It All in Your Head?: Implicit Theories About Willpower Affect Self-Regulation". Psychological Science, 21, 1686–1693.
Baumeister R.F., Bratlavsky E., Muraven M., & Tice D.M. (1998). Ego depletion: Is the active self a limited resource? Journal of Personality and Social Psychology, 74, 1252–1265.
Baumeister R.F., Vohs K.D., & Tice D.M. (2007). The strength model of self-control. Current Directions in Psychological Science, 16, 351–355.
Gailliot M.T., & Baumeister R.F. (2007). The physiology of willpower: Linking blood glucose to self-control. Personality and Social Psychology Review, 11, 303–327.
(Photograph courtesy of Edgar Chambon)