(CNN) A new study holds clues as to why we get so passionate about politics.

When your political views are challenged, the brain becomes active in regions associated with personal identity, threat response and emotions, according to the study.

"We think it's because political beliefs are important to our identity, to our sense of who we are. They are part of our social selves as well and can define who we spend time with and how they relate to us," said Jonas Kaplan, assistant research professor of psychology at the University of Southern California's Brain and Creativity Institute, who was lead author of the study.

"When the brain considers something to be part of itself, whether it's a body part or a belief, then it protects it in the same way," he said.

Now, the researchers hope that their findings could shed light on how to talk politics without provoking a brawl.

How politics makes us emotional

The study, published in the journal Scientific Reports last month, involved 40 healthy adults who identified themselves as politically liberal.

They were asked to read eight political statements that aligned with their beliefs, such as "Abortion should be legal" and "Taxes on the wealthy should generally be increased." They also were asked to read eight nonpolitical statements, such as "Taking a daily multivitamin improves one's health" and "A college education generally improves a person's economic prospects."

After reading each statement, each participant was shown evidence challenging the statement. While they were reading the statements and counter-evidence, their brains were scanned in a functional MRI machine.

Then, the participants completed questionnaires intended to gauge just how strongly they agreed with each statement they had seen.

After examining the brain scans, the researchers found that when the participants were presented with evidence that challenged the political statements they agreed with, increased activity occurred in the dorsomedial prefrontal cortex and decreased activity in the orbitofrontal cortex.

The dorsomedial prefrontal cortex is associated with emotion regulation and the orbitofrontal cortex with cognitive flexibility, Kaplan said.

"These are two regions we didn't specifically predict would play a role in our study, so we interpret them with some degree of caution," he said.

When presented with counter-evidence, "we found that people who showed more amygdala activity while being challenged were less likely to change their minds," Kaplan said.

The amygdala is a part of the brain associated with emotion, fear and anxiety.

The study finding suggests that increased amygdala activity may be associated with increased skepticism of the counter-evidence and could be an important neural signal that a person is less likely to be persuaded.

The amygdala -- the two almond-shaped areas hugging the center of the brain near the front -- tends to become active when people stick to their political beliefs, according to the new study.

Additionally, the researchers found that participants were significantly more likely to be persuaded to change their beliefs when provided with counter-evidence for the nonpolitical statements than for the political statements.

This chart shows how likely participants in the study were willing to reconsider their political beliefs compared with nonpolitical beliefs, with 0 being the least likely. Participants were more likely to adjust nonpolitical beliefs than political ones.

More research is needed to attempt to replicate the study findings in a group of conservatives or less strongly committed liberals, Kaplan said.

"There are also several ways in which political beliefs differ from nonpolitical beliefs, and from this study alone, we weren't able to explore them all to understand what is the real basis for the differences we found," he said. "For example, this group of people, chosen for their strong political beliefs, probably had more existing knowledge about the political topics we challenged compared with the nonpolitical topics."

Kaplan hopes further research could shed light on how to effectively challenge a political view without triggering an emotional response, he said.

Tips for talking politics

The new study is in line with prior research that also has showed how challenges to political beliefs are associated with emotional responses from the brain, said Drew Westen, a professor of psychology and psychiatry at Emory University in Atlanta and author of " The Political Brain ." He was not involved in the new study.

In order to effectively challenge someone's political views without triggering an emotional response, Westen said, your counterargument should do two things: solve the problem at the root of the political belief and address the values attached to the belief.

"The last thing to do is to try to argue someone out of a belief when they're strongly committed to it emotionally, because what makes it so strong is the emotion attached to it, not the facts or arguments that support it," Westen said.

In addition, "you solve the problem for them," he said. "You are addressing what their problem is, and when you do that, you don't have to fight with them about what the facts are, because you're going to change them."

Consider abortion , a hot topic that was included in the new study. Westen used the example of someone who is for abortion rights talking to someone with anti-abortion views to explain how to identify, address and empathize with someone's values to challenge beliefs.

The key is to identify the other person's values, even if they differ from your own.

"Words like 'reproductive health' sound like you're discounting their moral concerns and seeing this as just a medical issue. You don't want to come from a medical perspective," he said. "If you instead say, 'You know, I just don't like the idea of the government telling a woman or a couple when they should or shouldn't start their family.' ... Now you're activating two completely different neural networks than you've activated before: one about government interference in our private lives and the other about families."

He added, "it also makes this a man's issue and not just a woman's issue, so men feel, correctly, like they have skin in the game, too."

If you want to end a conversation before it gets heated, simply agree to disagree, Daniel Post Senning , an etiquette expert from the Emily Post Institute, said in November

"You are also not obligated to have these conversations," Senning said. "If you are willing to cede the last word or acknowledge that your opinions may differ, it's very hard to argue with that."

Join the conversation See the latest news and share your comments with CNN Health on Facebook and Twitter.

Now that neuroscientists better understand how the brain responds emotionally to political beliefs, it's equally important to study what happens in the brain when you might be persuaded to change your beliefs, Kaplan said.

"While it makes sense to defend the beliefs that are important to us, it's also crucial that we are able to change them when it's appropriate to do so," he said.