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They were “surprised at the pronounced difference.”

It’s no secret that conservatives and liberals don’t quite see eye to eye on politics, social issues, and pretty much everything in between — but these differences are deeper than just a matter of opinion, according to a new study.

New research at the University of Nebraska-Lincoln shows that the differences between the two groups may be psychologically fundamental. Led by Mark Mills, a graduate student of psychology in UNL’s Center for Brain, Biology, and Behavior, the team investigated something called “negativity bias,” which is when our cognitive processes put greater weight on negative information over positive or neutral information.

First and foremost, the researchers placed participants on a political scale based on their responses — approval or disapproval — to 20 hot-button political issues. Once they were sorted into different degrees of conservative or liberal, they were asked to study 120 images — negative, positive, or neutral — in order to prep for a memory test.

Next, the volunteers were shown 240 pictures and asked to identify the pictures they’d already seen. The researchers note that there was an even split of new and previously viewed images.

The researchers hypothesized that they would see differences in the memory of positive versus negative images between conservatives and liberals, but “were surprised at the pronounced difference,” according to the press release.

The conservative participants remembered about 91 percent of the negative images and 80 percent of the positive ones, while the liberal participants remember about 84 percent of the negative images and 86 percent of the positive ones.

"There are lots of reasons why people differ in how they process emotion," Mills said in a statement. "One part of the study was trying to account for how much of that variance is explained by political ideology. That had been unknown up until this point.”

Mills noted that 45 percent of the variance between study subjects was accounted for by political ideology.

"Out of all the possible reasons in the entire world for why individuals would differ in how well they remember positive and negative images, political ideology alone can account for about half of these reasons,” he said.

However, even though negative bias includes the word “negative,” it’s not necessarily a bad thing, according to the researchers. In fact, it’s part of human nature — everyone has it.

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"If you ignore a positive stimulus in your environment, you might miss lunch," said co-author Kevin Smith, a UNL professor of political science. "If you ignore a negative stimulus in your environment, you might be lunch, so there is good reason for why we have a negativity bias.”

Amazingly, Smith says that when conservatives are confronted with a negative stimulus and you track their physiology and neurology, you “tend to see reactions that are capable of distinguishing between liberals and conservatives.” Pretty intriguing.

While the study, which is published in the journal Behavioural Brain Research, highlighted this very fundamental brain difference between liberals and conservatives, Smith says that the cognition of the negativity bias needs to be further investigated since there wasn’t a lot done on memory itself.

Nonetheless, the research explains even on an intuitive level why liberals and conservatives are different,” Smith says. “There are distinct psychological differences between them.”

Given the radical differences between the conservative and liberal candidates in this year’s presidential election — it’s safe to say that there must be some fundamental differences in the brain activity of, say, Bernie supporters versus Trump ones.

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