Free Will in Social Psychology
Experimental studies on self-regulation carried out by my colleagues have gradually revealed vital things about how it functions. The folk notion of willpower appears to have considerable validity. That is, self-control depends on a form of energy (the will’s power) whose amount fluctuates. In our lab studies, after people exert self-control in one context, they tend to perform worse on a subsequent act of self-control, even if it seems completely unrelated to the first. For example, after people try to control their emotional reactions, their physical stamina is reduced, as an early study showed (Muraven, Tice, & Baumeister, 1998). In that study, participants watched a video and were told either to amplify or stifle their emotional responses, or they were given no instructions and just let their emotions happen. Compared to the no instructions condition, participants who had tried to change their emotional response later showed deficits on a handgrip endurance test.
Likewise, after participants resist tempting foods, they give up relatively easily on a difficult, frustrating task (Baumeister, Bratslavsky, Muraven, & Tice, 1998). In that study, hungry participants who resisted the temptation to eat chocolates and cookies and instead made themselves eat radishes later gave up faster on a difficult, frustrating task.
The implication of such laboratory findings is that people use up some of their willpower on the first task. That explains why they perform worse on the second task. For present purposes, the key point is that there is some energy resource that underlies self-control and thus one core form of free will.
Choice and Initiative
Most serious works on free will include self-control as an important category. But there are others. If there are several different behaviors that fit the general idea of free will and, crucially, that share some common psychological processes, then perhaps it is reasonable to start thinking that we are on the trail of understanding what free will is in practice.
Rational choice is one of the most important human traits. It signifies the ability to figure out what is the best thing to do and then to change behavior so as to do it. In philosophical writings about free will, rational choice is as prominent as self-control, if not more. Yet the philosophers had no way of knowing what social psychologists could establish with laboratory studies — that rational choice relies on the same “willpower” resource used in self-control.
Several sets of studies have shown the links. Let’s begin with being smart, which is one aspect of being rational. Logical reasoning and intelligent thought require willpower. After participants have engaged in an act of self-control and thereby depleted their willpower, their performance on intelligence tests was significantly reduced (Schmeichel, Vohs, & Baumeister, 2003). To be sure, some mental functions remained intact, but those requiring controlled processes such as reasoning were affected.
A next series of studies showed that people performed relatively poorly on tests of self-control if they had recently made choices (Vohs & Schooler, 2008). For example, after going through a list of pairs of consumer goods and choosing one from each pair that they would like to have, participants performed worse on the cold pressor task (trying to hold one’s hand in ice water for as long as possible), as compared to people who had thought about and rated all the same consumer goods but not made choices. The implication was that willpower was depleted by choosing, leaving less of it available for self-control. The will (free or otherwise) is thus involved in choosing as well as self-control.