Superb willpower is probably not the first attribute we associate with people who have spent years smoking. After all, if they had such good self-control, how did they end up hooked on cigarettes? Indeed, a growing number of studies have shown that smokers tend to act more impulsively than non-smokers. But psychology and neuroscience research also indicates that willpower is something that can be developed and enhanced with practice. And ex-smokers offer a compelling illustration of how this takes place.
While they once belonged to the same weak-willed camp as current smokers, those who have kicked the habit have had to repeatedly and successfully overcome the impulse to smoke. Neuroimaging studies have shown that resisting these urges engages the top and outermost regions of the brain, including many of the same dorsal-lateral regions of the prefrontal cortex associated with other types of cognitive control. Signals projecting from these regions appear to be critical in calming the activity deep within subcortical structures, such as the ventral striatum, where reward-seeking impulses are thought to originate.
So what is the result of frequently engaging the brain's control mechanisms in this way? Better self-control overall. Researchers recently examined brain scans of participants performing a task requiring strict control over behaviour, and found that ex-smokers performed better and showed greater activation of the dorsal-lateral prefrontal cortex than a group of individuals who still smoke. Moreover, the results indicated that the ex-smokers were even stronger on these measures of willpower than a group of people who had never smoked. Repeatedly exercising self-control while quitting appears to have lingering benefits for exerting control over other aspects of one's behaviour.
Such findings are important for everyone, not just those who have struggled with smoking, because each of our decisions and choice of actions is influenced by competing brain signals. French fries or a side of broccoli? Ranting soccer parent or a role model of sportsmanship for your kid? The lure of instant gratification and other emotional impulses are so often at odds with our long-term objectives that each of us could surely benefit from enhanced self-control.
Of all the methods for boosting the brain's control mechanisms, meditation - dedicated mental practice exerting control over the focus of attention and one's emotional response - appears to be particularly effective. Brain scans have also revealed meditation-related changes in the physical structure of the brain. The increased activity in regions of the prefrontal cortex associated with cognitive control is followed by an increase in the thickness and density of these regions, while the calming of activity in the amygdala is associated with a decrease in the density of this emotionally-intense region.
However, while exercising the brain's control mechanisms can enhance willpower and self-control in the long run, the cognitive and physiological demands of continuous engagement can exhaust their capacity. This may explain why someone who successfully stifles their irritation all day when dealing with an overzealous boss ends up snapping at their spouse or kids over something later on.
Research suggests the crash-and-burn following sustained acts of self-control may occur because blood-glucose levels become depleted. Glucose is the fuel that, along with oxygen, supports metabolic activity in neurons. When not fully available, the brain may be unable to effectively exert control, leading to self-control failures. Indeed several studies have shown that eating or drinking something to restore blood glucose can significantly reduce failures of self-control, even after prolonged periods of minding one's behaviour.
Regular physical exercise, eating small, frequent meals, and taking regular breaks help to maintain glucose levels and one's ability to exert self-control. It might just help you kick that bad habit, too.
Mark Fenske, co-author of The Winner's Brain: 8 Strategies Great Minds Use to Achieve Success, is an associate professor in neuroscience at the University of Guelph.