Why do things such as a new extreme sport or a viral video stunt become a trend, taken up by so many people, and what makes those people so like-minded? It's all about how the brain sorts out our preferences to taking risks, researchers say.

Scientists at Virginia Tech used brain scans to discover how those preferences affect how we perceive information coming from people around us, and how we act on that information.

In the study, the perceived value of taking a risk or gamble depended greatly on how other people chose to approach that risk, the researchers report in the journal Nature Neuroscience.

Whether or not you act on that perception depends on your personality, they say.

"You're more likely to follow the risky decisions of other people if you like to take risks, and you're more likely to follow the cautious decisions of other people if you tend to be cautious," said senior study author Pearl Chiu of Virginia Tech's Carilion Research Institute.

"Our data explain why this happens. The choices that others make become more valuable than they would be otherwise, and our brains are wired to choose things that are more valuable."

For the study, the researchers used functional magnetic resonance imaging to monitor brain activity of participants while they made choices about gambling, at first alone and then after seeing the choices other participants made.

Both risky and safe choice options observed in other people influenced the participants' choices to be riskier or safer than those choices made by themselves, the researchers found.

The findings suggest our preferences regarding risks also have an impact on our choice of peers more likely to influence our ultimate choices, the researchers say.

"The brain starts with your own preferences as a baseline for what to choose, and then, on top of that, the more your brain values information from other people, the more likely you are to follow their choices," said Chiu.

Since risk-takers and those who avoid risks live in the same world and receive the same available information on what might be a risk and what is safe, each individual will choose how to consider that information in their decision-making, said study first author Dongil Chung.

"As a relatively risk-averse person, I can be persuaded by my friends to go hiking," he said. "But no one is going to convince me to jump from one rooftop to another. For me, the risk is too extreme. Who you are is as important as who you are with."