In 2007, Drew Westen published a book called "The Political Brain: The Role of Emotion in Deciding the Fate of the Nation."

The Emory University professor and political psychologist had trained at Harvard University and spent 20 years in clinical practice before transitioning to academic work and research. But when "The Political Brain" was published, it caused a bit of a stir and a new sideline career. Westen argued in his book that emotions rather than reason drive many more of our political decisions than previously recognized — including the decision to cast a ballot. The brain is built for this, with most of our reasoning happening in a relatively small slice of the brain.

In fact, many of our decisions are so deeply rooted in our emotional "gut" that sometimes we are not even fully conscious of our responses to domestic and global events, only the political actions they inspire. Republicans, Westen argued, have mastered the art of the emotional appeal — or, at the very least, triggering and appearing responsive to people's emotions — helping to deliver electoral victories in races where Democrats tried to lean too hard on reason and their practical outgrowth, the 10-point policy plan.

It wasn't long before candidates started calling Westen looking for advice.

Now to be clear, Westen makes no secret of his political leanings. He is a Democrat. He has consulted for the campaigns of Democrats. And his view of emotion in politics and the masterful way that Republicans have used it has earned him some criticism, including from conservative New York Times columnist David Brooks. In fact, if you need some counter-arguments, consider Brooks's rational but hardly dispassionate review published when the book debuted.

But in the years since "The Political Brain" was first published, the field of political psychology has taken off and a number of studies have examined and even mapped political decision-making and differences in the personalities and emotional habits of liberals and conservatives. In short, the role of emotions in politics and the fact that different brains process events in distinct ways is no longer revolutionary or all that controversial.

At present, the political weight of human emotions seems clear. Within days of the Paris terrorist attacks, almost all of the nation's Republican presidential contenders and more than two dozen Republican governors voiced grave concern about admitting Syrian refugees to the United States. Several have called for an all-out moratorium, religious screening and starving the agencies that manage refugee resettlement of funding. Although the virtual cage match to be the most opposed to Syrian refugees continues, The Fix thought it might be wise to check in with Westen.

In the Q&A that follows — edited only for clarity and length — Westen offers some insight into fear and emotional gamesmanship in politics worthy of every voter's time.

FIX: First things first: What is a political psychologist? What are the primary questions they try to answer? 

WESTEN: It’s a whole range of things. The questions that are probably most interesting are questions about where do our political ideologies come from or even something as basic as what’s the psychology of the voter. What’s happening in their lives? And how do those events and emotions shape the way that individual people vote? What are the particular psychological qualities that lend themselves toward people becoming conservative or liberal or progressive? There’s even research now mapping or using neuro-imaging and genetics to understand how the brain is working in politics. That's what political psychologists generally study.

FIX: Are you saying there are differences in the actual brains of liberals and conservatives?

WESTEN: Oh yes. The magnitude of the difference is not enormous, but it is not small either. There was a longitudinal study that followed kids from the time they were very young. The researchers had them rated by preschool teachers and parents on all kinds of measures. They found that based on the ratings of their teachers on things like level of general anxiety, you could actually predict which kids were going to end up more conservative or liberal. Higher anxiety in preschool predicted a tendency toward conservatism in the 20s and 30s, and the differences were pretty substantial, too.

FIX: Okay, let's talk electoral politics. You have said gut emotions have much more influence on our politics than most people assume. But what are they, and is there a rank order? 

WESTEN: Gut emotions are our visceral and sometimes unconscious reactions to events, people, questions and so on. Typically, psychologists agree that at least eight basic emotions exist in humans everywhere. But there are probably just five major emotions you see guiding people in politics. And all the best politicians know how to use them.

On the positive side are hope and enthusiasm or excitement. They matter in politics a lot. And on the negative side, certainly, fear and anxiety matter a great deal, too. Psychology has only begun to distinguish between the two, but it's probably easiest to think of fear as immediate and intense — in the now. Anxiety is more anticipatory. You are worried that something may happen. Finally, lumped in with the negative emotions shaping politics, is anger. But I think that’s a mistake, because we can feel pleasure from anger, too. How many Americans were thrilled when they heard the news that we had killed bin Laden? We are normally not thrilled on the news of a death of another human being. But we were. Revenge can be sweet.

Which emotion outweighs the other is situational. If our embassy has been attacked somewhere in the world, anger is going to be a more dominant political emotion than fear. The opposite is true of attacks at home or what we perceive as closer to home. For instance, this attack by ISIS happened in Paris last week. We normally don’t care very much in the United States about what happens to Parisians. But in this case, when [Secretary of State John F.] Kerry said, "Tonight we are all Parisians," it's pretty likely the average American did feel that in their gut. We were not attacked in the United States, but the sense that we as members of the Western world were attacked, we as members of NATO or the community of countries that don't intentionally bomb nightclubs were attacked — that's what made the difference. So while there's some anger, fear appears to be looming much larger right now.

FIX: What does fear do politically?

WESTEN: The fear of mortality — not fear in general, but fear of death — tends cross culturally to shift people to the right. That's true in every country and every culture. It prompts people to more strongly hold to traditions, rituals. I don’t mean to belittle anyone's politics, but it should be understood as the political equivalent of the way that a child who is scared grabs on to a parent or latches on more tightly to a teddy bear. It offers comfort.

"Terror management theory" is what this is called technically. Study of this began about a decade before 9/11. And what these researchers have found is that if you trigger thoughts about mortality with a questionnaire about, say, burial vs. one about a dental procedure that might be painful, the people in that first group are more likely to take conservative positions on issue after issue after issue. This held even when the researchers gave the test to judges (people trained and paid to limit the influence of their emotions on their decisions).

That's part of the reason that the constant announcements and displays of threat levels during the [George W.] Bush administration were so effective politically. It had great mortality salience. In other words, it raised the specter and fear of death.

Now, that said, anger is very, very powerful, and you can also use it when people are afraid — it’s one of the primary things that demagogues do. When people are afraid, they then make those who are afraid angry at some group.

FIX: So, the attacks in Paris have had an immediate impact. Can we expect that to extend into November 2016?

WESTEN: The key to the next election is whether there is an attack somewhere else that Americans identify with. If that were to happen again, I think that would have enormous effects on the election. In the short term, I think we are already seeing some pretty clear effects. It's become a lot easier, maybe even popular to take a very visceral, one-dimensional position on the refugee issue since the attacks.

Politicians who say we will take no more Syrian refugees are automatically going to win over a certain portion of voters because it seems like the get it, they understand the voters' fear and are responding. Someone who tries to take a more nuanced position — that says the first job of government is to protect our people and that's what I am going to do, but we also all felt that for that poor 3-year-old baby whose picture we all saw a few weeks ago, so what we have to figure out is how to protect Americans, attend to human need but also stop ISIS from bringing their warriors in a Trojan horse to this country; we are not going to tolerate that, but we are also not going to tolerate conditions where we see dead 3-year-olds on the beach and the world is afraid to help them — that's a harder case to make.

But I think almost everyone can sense how that would work a lot better with voters than a purely rational argument. And that's what I fear. The biggest mistake that Democrats are prone to make here is skipping over the visceral and offering nothing but rational facts. This many refugees have been resettled. This many more are waiting. This many out of this many have been terrorist plots. The number is tiny. No one can make guarantees, but based on what we know and the screening process we use, the risk is small. But, it's always a lot easier to say, 'Those damn Muslims. We're not letting any more of them in. Or those Syrians. I'm really sorry about the babies but what matters most here is our safety.' Those simple ideas, not the nuanced ones, appeal purely to gut emotion.

Rational answers to a question that is ultimately visceral won't work alone. The visceral question here is: Are my children safe? Am I safe? Then the next question is: How do we remain true to American values at a time when this group is trying to get us to throw those values away and let refugees die?

To win with a more nuanced argument, you have to make this about terrorists vs. babies or refugees who are themselves victims of terrorism. Do you see the difference between that and laying some sort of equation about out the number of refugees welcomed by the United States or other countries and the one terrorist who may have slipped into France as a refugee? One is emotion plus nuance. The other is purely rational and expects voters to be that way when they are afraid.

Frankly, it comes back to evolution we evolve first and foremost to survive then reproduce. So we have to protect ourselves and we have to protect our families. And if we had ancestors 100,000 years ago who didn’t make those things priorities, they wouldn’t be in the gene pool today.

FIX: Well it sounds like figuring out how to trigger or enhance certain emotions — like fear — could be a very effective political strategy. True?

WESTEN: Sure. Some politicians are very good at triggering them intentionally and triggering our emotions in ways that are not designed to bring out reasonable feelings or thoughts but to bring about irrational actions — including voting against one's own interests.

Or playing sort of against type and using that to draw attention to an idea. I think a great example of that, even though I disagreed with most of his policies, was that moment when George W. Bush stood on that pile of rubble [at Ground Zero] and spoke into a bullhorn. He said said we were not at war with Muslims. Americans were hurting, scared and tired. But we would not give up the work there or the fight against the people who attacked us — terrorists. He was very clear. And coming from a Republican president, that was a particularly important point to be made. If the same point were made by a Democrat, it might not have been heard at all because voters expect Democrats to be more empathetic and Republicans to be more inclined to say, 'Let's go to war.' That speech was tremendously important.  It didn’t stop the hate toward people who didn’t deserve it, but my guess is it probably turned the volume down from 8 to 6.

FIX: Are there any warning signs or buzzwords that voters should look out for if they are trying to guard against emotional manipulation for political ends?

WESTEN: The first thing I would look for that is a warning sign is a complete lack of nuance, black-and-white thinking. I think another one to look for is if the fear or anger directed more broadly than would be accurate. So, right now, instead of being enraged and disgusted and afraid of Islamic terrorists who believe that killing people brings them closer to God, if a politician says or does things that aim to or actually rally anger against Muslims in general, suspicion and fear of an entire religious group that would be to me a good indicator.

The way that many conservative politicians tie together terrorism with [illegal] immigration from Latin America even though there has never been, to my knowledge, a terrorist who came across our southern border. Frankly it’s a lot easier to fly in. But making the connection without foundation or fact, indicting and then convicting entire groups, then using that to mobilize voters, that’s demagoguery. It’s using fear to create hatred, to win votes.

Another not completely distinct move is to create animus, group animus, in a way that one set of voters will fear and hate others and feel contempt toward them. That's called "othering" — particularly when that animus connected to national origin, color or religion.

That’s also when you should turn on that strip of cortex [part of the brain] that regulates rational thought and reason. Try very hard to use it.

FIX: If fear and the flight from death are part of the human brain and our survival instincts, what's wrong with voting that way? 

WESTEN: I’ve been asked that question now many times and in many countries now. What I always say is that when you look at the evolution of mammals and primates and ultimately the evolution of humans and various permeative invertebrates like worms who are — I was going to make a spineless joke but I will leave it alone — who have no spine, have a primitive form of reason. The same is true of pigeons. You can teach a pigeon to learn the difference between different genres of painting. Even pigeons can make some pretty fine distinctions.

What humans have is the most complex ability to make links and distinctions between what we feel and what we observe. We therefore ought to be able to distinguish between a Mexican [undocumented] immigrant who gets in trouble with the law repeatedly for, say, robbery from the vast majority who are very hard-working. That’s a distinction that humans are capable of making. And it's a distinction of both thought and feeling. Given that those workers pick the majority of our food, that ought to prompt us to be able to distinguish that group from this small percentage who abuse their spouses or are involved in gangs or robberies. If you can't, that’s when your emotions are serving you poorly. When they are serving you well, they either guide you toward your [political] interests or toward your values. It's an ability we have. We need to use it.