How the Brain Suppresses Willpower
Emotions Helped Our Ancestors Make Decisions
Emotions are an ancient evolutionary development. They helped our distant ancestors, who lacked complex analytical systems, make decisions in situations where information was critically scarce. If you were a small monkey, your main goal in life was to grow up and reproduce before the first passing tiger decided you’d make a tasty snack. Decisions had to be made quickly: there was no time to call a meeting or brainstorm whether to eat all the berries from a bush or save some for tomorrow. But you didn’t need help from colleagues: as soon as you spotted some delicious, sweet berries, there was no question—grab and eat them immediately. Emotions reliably guided animals on what to do, long before their slower thinking could reach the same conclusion.
This fast-acting emotional system helped us survive for millions of years precisely because it was tuned to make the “right” decisions from a biological standpoint. Food is good—eat it right away, and the sweeter and fattier, the better. Sex is very good—so do it as often as possible and with as many partners as you can (especially if you’re male). Tigers are bad—run away, and do it fast, rather than pondering whether the tiger could be a business partner under different circumstances. Rest, when nothing is chasing you, is wonderful—so if you have a chance to be lazy, you should take it. It’s all logical and straightforward.
Supermarkets, fast food, drugs, paid sex, and computer games are all recent inventions, and our emotional system hasn’t yet learned how to respond to them properly. Maybe in a few million years, our descendants will instantly feel disgust at the sight of candy bars or run away when they see an open social media page. But for now, our brains still consider what we call temptations to be good by default. These “hardwired” settings make it hard for us to exercise willpower. Fortunately, advanced mammals, including humans, have developed what’s called the neocortex—the “intellectual” part of the brain. Thanks to it, we think, speak, perceive ourselves as individuals, create, analyze, calculate, plan, and invent. Somewhere deep in the brain, at the intersection of its new and old regions, lies our ability to rein in impulses (with varying success), subordinating ancient, simple desires to complex modern goals.
Emotions Originate in the Limbic System
In Christopher Nolan’s excellent film “Inception,” the characters travel through the “limbo” of their target—a term used in the movie to describe the deepest level of sleep, the “pure subconscious.” Thanks to Nolan, the unfamiliar term entered everyday language, even among people far from neuroscience. In the real brain, the limbic system is indeed crucial—though it has nothing to do with Nolan’s “pure subconscious.” In Latin, limbus means border or edge, and in the brain, it’s the border between the neocortex and older structures (more precisely, between the neocortex and the brainstem). This area looks like a ring with branches, and in anatomy textbooks, it’s called the limbic system.
This is where all our emotions “reside”—from anger and rage to joy and bliss. Mother rats whose limbic systems were intentionally damaged completely lost interest in their pups, stopped feeding them despite their desperate squeaks, and acted as if the pups were inanimate objects. Even more impressive than destroying the limbic system is overstimulating it. In 1954, American physiologists James Olds and Peter Milner decided to see what would happen if they stimulated certain areas of rats’ brains with electricity. They implanted electrodes in the rats’ heads and activated them when the animal entered a specific corner of the cage. At the time, the brain’s fine anatomy was poorly understood, and the researchers, without realizing it, hit the very “heart” of the limbic system—the famous pleasure center. To their surprise, after a few shocks, the rats began to seek out the corner instead of avoiding it. Realizing that stimulation of this area brought pleasure, the researchers connected the electrodes to a lever so the rats could turn on the current themselves. Once they discovered this, the animals stopped eating and drinking, spending all day pressing the lever—some managed to do it up to 700 times an hour!
Emotions Instantly Change Our Physical State
Olds and Milner’s experiments clearly show that emotions can radically change behavior. Moreover, the limbic system directly regulates our physical state: its signals (via the hypothalamus) trigger a whole set of reactions that either relax the body or, on the contrary, put it into a state of combat readiness (in English, this is called “fight or flight”).
When relaxed, the body is ready for all kinds of pleasures: it increases saliva production, boosts intestinal activity and digestive juices for a good meal, lowers blood pressure and reduces lung ventilation for proper rest, and stimulates erection for enjoyable sex. In a state of anxiety, functions unrelated to fighting or fleeing are ruthlessly suppressed, and all resources go to the muscles, lungs, and circulatory system. A special role in activating the “fight or flight” state belongs to the amygdala—a small area inside the temporal lobe (each hemisphere has its own amygdala). The amygdala can receive and analyze sensory information even before the cerebral cortex processes it. In other words, you haven’t yet realized that a tiger has jumped out of the bushes, but you’re already running in the opposite direction, amazed at how fast you can move.
To launch all these complex reactions and either relax or energize the body, the hypothalamus sends commands to parts of the nervous system that directly control internal organs. The part responsible for relaxation and recovery is called the parasympathetic nervous system, while the part controlling the “fight or flight” state is the sympathetic nervous system. Even from this simplified description, it’s clear how much the limbic system can change the body’s functioning and how much its influence was underestimated by proponents of the “pure reason” theory. How can you resist ordering pizza for dinner when your mouth is already watering, your stomach is growling, and a pleasant warmth is spreading through your body? The rational mind may warn you that the scale will soon show something unpleasant, but its advice comes too late and doesn’t trigger nearly as strong a response. The limbic system is powerful and demanding: we literally feel its commands physically, because their goal is nothing less than to save our lives and pass our genes on to the next generation. We are programmed to automatically react to the most important survival stimuli, and there’s no way to cancel this program.
The limbic system is closely tied to our ability for self-control. While it may seem that, for evolutionary reasons, it prevents us from being strong-willed and determined, in reality, it’s a powerful machine that can be used to strengthen willpower. But to understand how, we first need to see how the advanced neocortex tries to restrain our unruly impulses.
We Are Our Neocortex
From an evolutionary perspective, the neocortex is a very recent development. Mammals acquired this extra “blanket” of several layers of neurons covering the “old” brain about 280 million years ago, or possibly even later. In early mammals, the neocortex was a tiny outgrowth of older brain areas, with a surface area of just 1–5 cm², offering no major advantages. In humans, the neocortex has grown to an impressive 800 cm² and makes up 80% of all gray matter. In many ways, Homo sapiens is defined by the neocortex: this part of the brain is responsible for consciousness, thinking, and everything else that sets us apart from other animals. Scientists divide the neocortex into many parts based on their structure and assigned tasks, though, as mentioned above, the specialization of each part can vary to some extent, but not too much.
The Anterior Cingulate Cortex Helps Us Resolve Conflicts Between Actions and Goals
The main area essential for controlling impulses is the anterior cingulate cortex (ACC). It’s part of the so-called reward system (which reinforces behaviors beneficial for survival) and provides emotional coloring to behavior. Thanks to this area, we even realize that something needs to be restrained. On MRI scans, the ACC lights up when a person faces a conflict situation—for example, trying to name the correct color of letters in the Stroop test (where the word “red” might be written in blue letters, and you have to suppress the strong urge to read the word instead of naming the actual color).
The ACC also activates in other situations where the brain needs to overcome a contradiction—such as between true thoughts and social norms. A typical case is confronting racial stereotypes. The anterior cingulate cortex acts as a bodyguard, vigilantly tracking emerging conflicts.
Research has shown that the ACC automatically “turns on” when a conflict arises (like the urge to smoke in someone trying to quit), but the degree of activation varies from person to person. In other words, due to “design” features of the brain, some lucky people are better at filtering out conflicts between immediate and long-term goals than those less fortunate with their ACC, and consciousness doesn’t participate in this process. If there’s no conflict, the brain sees no reason to suppress impulses—so the limbic system gets to grab another candy or say something inappropriate. This flawed pattern works even when, at the conscious level, a person believes sugar is harmful or that racial prejudice has no place in modern society.
The ACC Can Be Trained to Do Its Job Better
Here’s the not-so-great news: those who aren’t lucky enough to have a “well-built” ACC will regularly fall victim to their passions, even if they don’t want to. But it’s not all bad: several experiments have shown that strong internal motivation to resist the limbic system’s tricks helps people better control their impulses. In other words, if you regularly remind yourself that excess weight is dangerous to your health, or that it’s shameful for a civilized person to consider any group inferior, sooner or later your efforts will pay off, and you’ll learn to notice and stop automatic reactions. Importantly, this kind of training teaches you to see the conflict, but it won’t help you stop a wrong action if it’s already started—other systems are responsible for that.
But you can only train the ACC using internal motivation. If you’re just following external prompts, you might be able to restrain yourself in a specific situation, but as soon as the “supervisor” is gone, you’ll revert to old habits. That’s why so many people work out diligently with a trainer at the gym but can’t do the same exercises on their own, even if they’ve mastered the technique perfectly.