Abstract: A currently popular model of self-control posits that the exertion of self-control
relies on a resource, which is expended by acts of self-control, resulting in less of this
resource being available for subsequent acts of self-control. Recently, glucose has been
proposed as the resource in question. For this model to be correct, it must be the case that
A) performing a self-control task reduces glucose levels relative to a control task and B)
performing a self-control task reduces glucose relative to pre-task levels. Evidence from
neurophysiology suggests that (A) is unlikely to be true, and the evidence surrounding (B)
is mixed, and is unlikely to be true for subjects who have not recently fasted. From the
standpoint of evolved function, glucose might better be thought of as an input to decision
making systems rather than as a constraint on performance.
Keywords: self-control, glucose, brain metabolism, optimal foraging