The brain gets tired too!
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You’re staring down a pack of Oreos someone left on the dining room table. It’s late in the day and you’re exhausted. Your mind is telling you not to eat the cookies; after all, you are trying to be healthier. Still, you really want those cookies. Eventually, you give in and eat a whole stack.
Earlier in the day, you might have avoided eating those cookies. Why is it so much easier to make your decision at eight in the morning as opposed to ten at night?
Decision making is partially affected by a temporary condition called decision fatigue. Just like our bodies expend energy during the day, our minds experience a similar fatigue when it comes to cognitive processes. We have the means to process a lot of information, but because of this, our processing systems require a lot of energy to function. Areas in the prefrontal cortex & striatum are involved in the decision making process. In the striatum, there are three main parts that together create and finalize a decision. The ventral striatum and ventromedial prefrontal cortex are the first involved in the process, drawing on past experiences and knowledge in order to make an educated decision. The dorsomedial striatum then weighs the risk versus reward of the decision at hand. Finally, the dorsolateral striatum starts the motor functioning required to act upon the decision that is made.
Whew! That’s a lot of cognitive effort! Having a complex decision making system with many working parts can be exhausting to our brains. Just like working out your body, decision making can exacerbate mental fatigue.
The fact that you’re more likely to snack unhealthily at the end of the day is a result of your mind using a lot of energy making other decisions throughout the day. Any conscious choice you make in the day will subtract from the energy your brain is willing to expend for a new decision. By the time you reach the point of the day where you see the cookies on the table, your brain is fatigued and doesn’t want to expend as much energy to override impulses. As a result, you might be more inclined to eat something tempting.
In tandem with decision fatigue, exercising self-control can become more tiring once mental energy is depleted. Studies have indicated the growing difficulty of self-control after having restrained oneself prior to the present situation. When presented with the positive experience of eating a cookie, a fatigued mind likely will not want to expend energy exercising self-control. This makes you even more likely to look for something tasty to eat that will satisfy your craving.
You may be more prone to unhealthy eating if it becomes a habitual activity. As a result of decision fatigue, individuals are more likely to resort to habits. Because the mind doesn’t want to use more energy, it’s most likely to choose the path of least resistance. Habits function as a low-risk reward that the brain has encountered in the past, making them easy to fall back on when the brain is fatigued. In studies investigating decision fatigue, judges offering parole for prisoners were less likely to offer parole after spending multiple hours in the courtroom, and healthcare workers were more lenient with hygiene standards further into their shifts. In the courtroom, the path of least resistance taken by the judges is to leave prisoners in jail, thus avoiding releasing someone dangerous and making the legal process more simple. In the case of healthcare professionals, the path of least resistance involves spending less time washing hands and cleaning to prioritize efficiency. In the case of cookies, cravings are prioritized over the long term reward of being healthier. The lapses in objective reasoning in each scenario are encouraged and reinforced by habit.
In more severe cases where the brain suffers lesions in the prefrontal cortex and striatum, bigger lapses in judgement can be made, causing a tendency to favor riskier behaviors and less rational decision making. Similar effects can be seen in people who suffer from addiction, perpetuating the cycle of abuse of a substance or activity. While these afflictions display similar characteristics to decision fatigue, permanent alterations to the brain are prolonged, whereas decision fatigue can be remedied by resting or refraining from making too many decisions in a given period of time.
So why is decision fatigue a thing? Isn’t there an easier way to make decisions?
Decision fatigue stems from an evolutionary trait that allows for more diversity in choices. It is a side effect of having more taxing and complex cognitive processing systems. If humans were to have decreased decision fatigue, our brains would have less options when making choices. Organisms with what are called “fixed-action patterns” don’t have the mental capacity to view the variety of decisions that we might experience. Instead, their “choice” is substituted with an instinct determined by their mental programming. Once choice is eliminated from the equation, decision fatigue is no longer an issue. Therefore, a decrease in mental fatigue also means a sacrifice of free will.
Now that you know a bit more about decision fatigue and its effects, what should you do about it? If your mind gets tired when making decisions, how are you supposed to alter your behavior?
You might think that leaving someone else to make decisions for you might be a good idea. Unfortunately, other people aren’t as good at knowing what you want as you are, so generally, this leads to a type of distress where one would have to expend mental energy adapting to an unsatisfactory choice. It’s better to stick to making your own decisions.
No matter what, decision fatigue will remain a natural mechanism to conserve mental energy. Luckily, though, there are some things that can help. Mindfulness has proven to be useful in combating impulse. Instead of falling into habit, be mindful about what outcome would align more with your goals. By spending a few seconds to think about a choice, you can allow yourself to think more objectively about what the best outcome would be. In doing so, you are also able better resist the initial urge to eat a whole stack of Oreos, and instead opt for a healthier option, saving yourself the guilt or remorse that may follow. In turn, your conscious decision will help break that habit, replacing a bad habit with a new, preferred habit and help you make decisions that you are more happy with for the future.
Of course, letting yourself eat a few cookies wouldn’t hurt!
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Hiser, Jaryd, and Michael Koenigs. “The Multifaceted Role of the Ventromedial Prefrontal Cortex in Emotion, Decision Making, Social Cognition, and Psychopathology.” Biological Psychiatry, U.S. National Library of Medicine, 15 Apr. 2018, www.ncbi.nlm.nih.gov/pmc/articles/PMC5862740/.
Persson, Emil, et al. “The Effect of Decision Fatigue on Surgeons' Clinical Decision Making.” Health Economics, John Wiley and Sons Inc., Oct. 2019, www.ncbi.nlm.nih.gov/pmc/articles/PMC6851887/.
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