Why Willpower Fails: Insights from Cognitive Neuroscience
The decision to begin a diet or any new pattern of behavior, such as exercise, originates in the prefrontal cortex along with some support from the limbic system. The limbic system is involved because some level of emotional dissatisfaction with the current situation generally motivates the change.However, here is the rub: apart from the flight or fight response, the goal-directed behavior and habitual routines that the prefrontal cortex has to work with come from the basal ganglia. Those goal-directed behaviors and habits were acquired over time and through repeated trials. The reason why they formed in the first place was because they worked and led to success in achieving sought-after rewards (physical or psychological) under similar situations.
When a person abruptly changes their behavior however, such as when adopting a new diet or quitting smoking, that behavior is not supported by habit. Any associations of the new behavior with goal-achievement exist only conceptually in the prefrontal cortex. It has yet to penetrate the subcortical centers of the basal ganglia. The prior programming of the basal ganglia is still alive and well. All those old habits are still there.
When these habits and goal-directed routines are automatically primed, they are very difficult to resist, especially if they’re highly motivated. For example, a highly desirable dietary item (e.g., a piece of cake) now restricted by the parameters of a new diet enters your perceptual field and is detected by the frontal eyelid fields. Before you know it, the orbitofrontal cortex is busy priming the nucleus accumbens of the basal ganglia. This activates the substantia nigra to pump out dopamine increasing the motivation to obtain the reward. The habits and goal-directed action routines are activated and sent to the prefrontal cortex. Emotionally, the “system” expects the reward. This all happens before even a second has passed. In the next instant, you’re reaching for a plate and putting a piece of cake on it.
This is what is supposed to happen. The deep centers of the brain don’t know that a change has occurred. From their perspective, it is full speed ahead in pursuit of the old goals.Instead, the prefrontal cortex says “no,” and, for a brief moment, it wins.
However, it doesn’t end there. The original importance of the object is still intact. So, the orbitofrontal cortex keeps signaling basal ganglia centers, which activate the relevant goal-directed actions (e.g., moving to get a piece of the cake). This process is nonstop as long as the goal is attainable. As a result, the prefrontal cortex is forced to continuously inhibit these habits from taking over based on the new diet directive. The system is under pressure, to say the least.
This puts the prefrontal cortex in a precarious position: Willpower is being applied to not only make minor adjustments to habits and goal-directed behaviors, but also to stop them entirely. It is like rallying your strength and motivation to lift a heavy bar over your head, but then keeping it there. You might be able to hold that weight up for a moment, but something eventually has to give. When the limbic system steps in and registers emotional disappointment due to your failure to gain the expected reward, willpower failure happens faster.
The effort to inhibit motivated habits is not without cost. The demands of self-control put strain on the system, resulting in emotional discomfort and stress. Couple that with the fact that willpower and its ability to exert self-control is a limited resource and you see that willpower failure is all but certain. Something as simple as insufficient glucose in the system can contribute to willpower failure. Additionally, many things can contribute to the failure of willpower, including cognitive stress, emotional stress, and susceptibility to subliminal primes when distracted.
This obviously raises another question: What can you do?