Monday, August 12, 2013
Will Power and Its Limits
How to strengthen your self-control.
Reason in man obscured, or not obeyed,
Immediately inordinate desires,
And upstart passions, catch the government
From reason; and to servitude reduce
Man, till then free.
—John Milton, Paradise Lost
What is will power? Is it the same as delayed gratification? Why is will power “far from bulletproof,” as researchers put it in a recent article for Neuron? Why is willpower “less successful during ‘hot’ emotional states”? And why do people “ration their access to ‘vices’ like cigarettes and junk foods by purchasing them in smaller quantities,” despite the fact that it’s cheaper to buy in bulk?
Everyone, from children to grandparents, can be lured by the pull of immediate gratification, at the expense of large—but delayed—rewards. By means of a process known as temporal discounting, the subjective value of a reward declines as the delay to its receipt increases. Rational Man, Economic Man, shouldn’t behave in a manner clearly contrary to his or her own best interest. However, as Crockett et. al. point out in a recent paper in Neuron “struggles with self-control pervade daily life and characterize an array of dysfunctional behaviors, including addiction, overeating, overspending, and procrastination.”
Previous research has focused primarily on “the effortful inhibition of impulses” known as will power. Crockett and coworkers wanted to investigate another means by which people resist temptations. This alternative self-control strategy is called precommitment, “in which people anticipate self-control failures and prospectively restrict their access to temptations.” Good examples of this approach include avoiding the purchase of unhealthy foods so that they don’t constitute a short-term temptation at home, and putting money in financial accounts featuring steep penalties for early withdrawal. These strategies are commonplace, and that’s because people generally understand that will power is far from foolproof against short-term temptation. People adopt strategies, like precommitment, precisely because they are anticipating the possibility of a failure of self-control. We talk a good game about will power and self-control in addiction treatment, but the truth is, nobody really trusts it—and for good reason. The person who still trusts will power has not been sufficiently tempted.
The researchers were looking for the neural mechanisms that underlie precommitment, so that they could compare them with brain scans of people exercising simple self-control in the face of short-term temptation.
After behavioral and fMRI testing, the investigators used preselected erotic imagery rated by subjects as either less desirable ( smaller-sooner reward, or SS), or more highly desirable ( larger-later reward, or LL). The protocol is complicated, and the analysis of brain scans is inherently controversial. But previous studies have shown heightened activity in three brain areas when subjects are engaged in “effortful inhibition of impulses.” These are the dorsolateral prefrontal cortex (DLPFC), the inferior frontal gyrus (IFG), and the posterior parietal cortex (PPC). But when presented with opportunities to precommit by making a binding choice that eliminated short-term temptation, activity increased in a brain region known as the lateral frontopolar cortex (LFPC). Study participants who scored high on impulsivity tests were inclined to precommit to the binding choice.
In that sense, impulsivity can be defined as the abrupt breakdown of will power. Activity in the LFPC has been associated with value-based decision-making and counterfactual thinking. LFPC activity barely rose above zero when subjects actively resisted a short-term temptation using will power. Subjects who chose the option to precommit, who were sensitive to the opportunity to make binding choices about the picture they most wanted to see, showed significant activity in the LFPC. “Participants were less likely to receive large delayed reward when they had to actively resist smaller-sooner reward, compared to when they could precommit to choosing the larger reward before being exposed to temptation.”
Here is how it looks to Molly Crockett and her fellow authors of the Neuron article:
Precommitment is adaptive when willpower failures are expected…. One computationally plausible neural mechanism is a hierarchical model of self-control in which an anatomically distinct network monitors the integrity of will-power processes and implements precommitment decisions by controlling activity in those same regions. The lateral frontopolar cortex (LFPC) is a strong candidate for serving this role.
None of the three brain regions implicated in the act of will power were active when opportunities to precommit were presented. Precommitment, the authors conclude, “may involve recognizing, based on past experience, that future self-control failures are likely if temptations are present. Previous studies of the LFPC suggest that this region specifically plays a role in comparing alternative courses of action with potentially different expected values.” Precommitment, then, may arise as an alternative strategy; a byproduct of learning and memory related to experiences “about one’s own self-control abilities.”
There are plenty of caveats for this study: A small number of participants, the use of pictorial temptations, and the short time span for precommitment decisions, compared to real-world scenarios where delays to greater rewards can take weeks or months. But clearly something in us often knows that, in the immortal words of Carrie Fisher, “instant gratification takes too long.” For this unlucky subset, precommitment may be a vitally important cognitive strategy. “Humans may be woefully vulnerable to self-control failures,” the authors conclude, “but thankfully, we are sometimes sufficiently far-sighted to circumvent our inevitable shortcomings.” We learn—some of us—not to put ourselves in the path of temptation so readily.
Crockett M., Braams B., Clark L., Tobler P., Robbins T. & Kalenscher T. (2013). Restricting Temptations: Neural Mechanisms of Precommitment, Neuron, 79 (2) 391-401. DOI: 10.1016/j.neuron.2013.05.028
Photo Credit: http://tommyboland.com/2011/05/27/white-knuckle-living/