Via a very interesting post on willpower from the blog Psychology of Wellbeing comes a link to a very interesting paper on willpower and ego depletion (PDF). Both are well worth a full read, but here’s the money quote from the latter (cites removed, emphasis mine) suggesting that willpower may not be as limited as we think it is:
The present research suggests that implicit theories changed how people responded given their level of felt exhaustion on the initial task. People led to adopt a limited-resource theory performed worse the more exhausted they felt. But for people led to adopt a nonlimited-resource theory, there was no relationship between perceived exhaustion and subsequent performance. For them, exhaustion was not a sign to reduce effort.
Taken together, the results suggest that in some cases, ego depletion may result not from a true lack of resources after an exhausting task, but from people’s beliefs about their resources. We do not question that biological resources contribute to successful self-control. But these resources may be less limited than is commonly supposed. …
It is important that people understand that their own beliefs about willpower as a limited or nonlimited resource can affect their self-regulation.
I suspect that this same phenomenon may be at work in why abstention is useful as an addiction tool.