Willpower refers to effort we make to control our impulsive behavior. Willpower can be viewed as a resource, implying that there is something in the deliberative mind that is limited. That is, engaging in acts of self-control draws from a limited resource of will that becomes depleted over time, just as a muscle becomes tired after a period of exertion. When resources are depleted, people tend to act on impulse and are more likely to be swayed by their desires, urges, and cravings, although they may regret in the long run.
These are the five key factors that can temporarily weaken willpower and lead to impulsive reactions:
- Ego depletion. Making a series of decisions that involve conflict—trying to impress others, responding kindly to rude behavior, or planning a wedding—leads to ego depletion, and ego depletion leads to a loss of motivation. Thus, at the end of a long day, people have fewer resources to overcome the urge to consume a tempting snack than at the beginning of the day. This explains why most diets are broken at night!
- Busyness (cognitive load). The busier people are, the more likely they will behave impulsively. In a moment of stress, we often forget the names of people we know well. When our mind is preoccupied, our short-term mind guides our choices. This insight suggests that shoppers distracted by music or displays will be more likely to increase their impulse purchases. In contrast, being deliberate allows one to see the overall context and be less concerned with sensation.
- Stress. Coping with stress involves using willpower to control behavior. Daily stress can cripple the prefrontal cortex, the brain’s executive function that moderates concentration, planning, decision-making, and judgment. As a result, we lose the ability to be reflective, and begin to function on automatic default. For example, even with the best preparation, the pressure and anxiety of a lengthy exam (or interview) often causes test takers’ reasoning abilities to slow or even shut down entirely. This experience is known as blanking out, or choking under pressure.
- Alcohol. Intoxication reduces your resistance to temptation and weakens inhibitory control. Intoxication reduces self-awareness and narrows the scope of attention, limiting the ability to attend to multiple cues. As drinkers’ awareness declines, they lose self-control, so they eat more or smoke more as well.
- Blood sugar. Glucose is a vital part of willpower: Evidence shows that exerting willpower lowers blood sugar, which reduces the capacity for further self-control. Brains are energy hogs. Your brain uses about 20 percent of the energy your body consumes. Ironically, caloric restriction in dieting produces lower glucose, which undermines the willpower needed to resist food intake. The glucose itself doesn’t enter the brain, but it’s converted into neurotransmitters like serotonin. A lack of neurotransmitters increases impulsivity. For example, people with hypoglycemia, the tendency to have low blood sugar, are more likely to have trouble concentrating and controlling their negative emotions when provoked. Evidence suggests that schoolchildren who skip breakfast perform worse on tests—but will do better after a snack.
The scarce-resource model of willpower provides insight into strategies that can be used to improve our self-control capacity. We need to treat willpower as a limited and important resource. We use the same supply of willpower to deal with frustrating traffic, tempting food, annoying colleagues, and disappointed children. Thus, resisting dessert at lunch can leave you with less willpower to deal with your annoying colleagues later.
A general guideline is to focus on one project at a time. Concentrating your effort on one or, at most, a few goals at a time increases the odds of success. For example, it makes no sense to decide that one is going to quit smoking and diet if one does not actually possess the necessary willpower. As the saying goes, “He who grasps at too much loses all.”
Finally, the willpower model suggests that self-control capacity can be built up through practice and training. Engaging in simple daily self-control exercises, such as avoiding unhealthy foods, lead to improved long-term maintenance of the behaviors. Further, the state of ego depletion can be reversed through rest or relaxation. Sleep deprivation may lead to chronic state of ego depletion and poor performance.