Pollsters, politicians, much of the press and public are dismayed by Donald Trump’s surprising victory in the presidential election, but not neuroscientists. The bewilderment arises from an attempt to comprehend the election result rationally, but rage, not reason, is what drove people to put Trump in the White House.

Emotions are powerful motivators of behavior. For most animals, emotion, not rational thought is what drives behavior, and this remains true for our esteemed species, self-christened as Homo sapiens—“the wise one.” But our decisions are not made solely by reasoning. In fact, in the most complex and momentous decisions we make we rely on emotion—gut feelings. Whom to marry, where to live, or even what entrée to select from a dinner menu, are decisions we make not by reason, but rather by how we “feel.”

We have emotions because we need them. They arise from an astonishing neural network that performs an extremely complex, instantaneous analysis of our situation and sets us upon a definitive course of action. To accomplish this, input from all of our senses streams into the brain’s limbic system to assess our internal and external state, constantly sifting the data stream on the lookout for danger. All of this information processing operates below the level of consciousness and rational thinking, because the enormous amount of information processing involved would overwhelm our conscious mind. We can hold no more than a pitiful string of seven digits in working memory on average, which is why the simple steps of long division requires a pencil. When faced with very complex situations, it is our deep brain threat assessment circuitry, not only our cerebral cortex, that most often moves us to action. Especially so when our fundamental wellbeing is at stake. But language arises from neural circuitry in the cerebral cortex, so the brain’s subcortical threat detection system does not communicate with words, but rather by using multicolored emotions. Each emotional feeling communicates clearly to our conscious awareness the specific type of threat confronting us: hunger, fear, loneliness, alienation, jealousy, frustration—a rainbow of infinite colors, but every one a brilliantly distinct hue of meaning.

Many in this country feel angry, fearful, and threatened. These feelings arise from perceptions of personal risk, social disruption and alienation, imminent threats of terrorism, and a chronically dysfunctional government. The pollsters got it wrong because the act of asking the question carries the implicit assumption of a rational explanation. But rage is not a reason. And emotions are not always accessible by self-assessment—“I’m not angry!” he screamed at her. People are angry, and the emotion of anger serves only one purpose—to prepare you to fight.

Fighting for all animals is risky, and so only a very few specific triggers will activate the neural circuits that launch us into a violent rage. These neural circuits of defensive rage are being identified, and with this new information the outdated “lizard brain” notion of our limbic system driving us to do beastly things is being replaced by a far more detailed understanding. Different types of threats activate different circuits of rage and defensive aggression in our brain. Most of these circuits are deeply engraved by evolution in the brains of our primate and mammalian ancestors. A mother’s instant reaction to respond with unlimited aggression if necessary to protect her child is a familiar example. The human brain shares this same neural circuitry with other animals, and that circuit is separate from the neural circuit that launches us into defensive aggression in response to another type of danger, facing an intruder for example. To understand this election you must understand the brain’s threat detection mechanism.

As a social species, our individual survival is utterly dependent upon being a member of a group or tribe, and the brain circuitry that allows us to instantly classify anyone into either “us” or “them” is located in our prefrontal cortex. These circuits interact with the limbic system provoking rage and violent aggression to maintain social order, protect our own tribe, and slaughter another tribe if necessary for our self-preservation. The core of fear and anger gripping many people today stems from this neural circuitry of defensive aggression and rage to protect one’s own tribe. This is true for supporters of both candidates, whether it be working class men feeling their livelihood taken away, women feeling denied opportunity and respect, political parties threatened by their competing parties, or races of people feeling displaced, rejected, excluded, or individuals denied their fair share of our nation’s wealth.

This neuroscience perspective explains the seemingly incomprehensible situation of a privileged billionaire becoming the champion of working class men and women who are feeling angry and threatened. It is boggling to provide a logical explanation for this improbable hero of the working class, but his appeals to the anger, fear, and frustration that many feel—an appeal to the brain’s limbic system—is perfectly consistent with how the human brain makes complex decisions by relying on emotion when faced with momentous decisions. Perfume is not sold by describing how it will make us smell; it is sold by how it will make us feel. So it is with selling real estate. And rationally we know that all cars travel at the same speed on our roads. How then can we rationally explain the need to purchase a 500 horsepower Corvette, when it will ride the bumper of a jalopy in traffic, but cost 10 times as much? Marketing skillfully manipulates emotion—tapping into how we feel—to nudge our purchasing decisions.

The problem is that the brain’s threat-detection system operates in real time, and our emotions are assessments of our current status. It is impossible to feel love or hate for someone you have not yet met. This is why the cerebral cortex has connections to the limbic system to override the urgent urges evoked on a moment-to-moment basis. Reason can plan and strategize for the future, and we have this cognitive ability for a vital purpose—to avoid the dire consequences conveyed by the emotion we call “regret.”

The people have spoken and we will all live with the consequences. Every person who voted did so by relying on all the decision making abilities their brain could provide them, both reason and rage. The election exposed a deep rift in society, chilling fear and ugly tribalism. Whether these real divisions in society will explode into factionalism or unite us will be determined by the same neural circuitry in our prefrontal cortex that separates “us from them.” Either this circuitry will divide us or unite us with the realization that no matter what differences we may have, we are nevertheless united by a larger common purpose and group—citizens of the United States. The electorate has concluded that the best person to succeed in manipulating this neural circuitry so vital to our survival is not a statesman, but rather a salesman. Time will tell.

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