UC Berkeley study finds people’s beliefs influenced by what others think

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A campus study found that people tend to unconsciously use the popularity or commonality of a belief to shape their own stances.

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A study by researchers at UC Berkeley’s Kidd Lab found that people unconsciously track others’ beliefs to determine beliefs of their own.

According to lead author and campus doctoral candidate Evan Orticio, a belief perceived to be more popular by a person is also seen as more believable, even when the person does not have any supporting evidence. Campus professor of psychology Celeste Kidd added that when an individual is unsure about something, the commonality of the belief influences them more heavily when deciding what to believe.

“If a belief is more common than you expect, you’re more likely to believe it yourself,” Orticio said in an email.

To analyze this behavior, Orticio’s team surveyed American adults about how likely they thought certain statements, some of which were pseudoscientific, were true and how common the beliefs were.

Researchers then showed participants a purported sample of 10 responses that either adhered to the participants’ initial estimates about how common the beliefs were or a sample that exaggerated the numbers to make the beliefs seem more popular.

“In that latter case, where participants were shown that a belief was unexpectedly popular, they were more likely to change their own beliefs in line with that social data,” Orticio said in the email. “Data about just 10 anonymous survey respondents was enough to make people endorse pseudoscientific and conspiratorial claims more strongly.”

While misinformation is not new, the rise of social media and machine-generated news content can accelerate the spread of misinformation, according to Orticio and Kidd.

Kidd noted that artificial intelligence language models can generate “human-like” content, which can be used to churn out “fake news stories” to attract clicks and sell advertisements.

“If the point is just getting eyeballs on the screen to collect money for ad sales, it doesn’t matter if it’s true,” Kidd said. “That, in combination with how people adopt beliefs, can be dangerous.”

Meanwhile, Oriticio noted that social media allows people to “carefully curate” the content they want to see and can affirm people’s beliefs.

Metrics, such as likes and reposts, can further exaggerate belief adoption since people may think the belief is more popular than expected, according to Kidd.

“Past research has shown that fake news is more likely to go viral than true news on platforms like Twitter,” Orticio said in the email. “We now know that the mere state of being viral—seeming more popular—also makes information more believable, even without any direct evidence.”

Both Orticio and Kidd said they hope individuals will carefully verify sources, particularly before sharing information.

Social media platforms, Orticio believes, have a responsibility to moderate their content and algorithms to prioritize reputable information, perhaps by hiding social engagement metrics from posts that contain misinformation.

“It’s hard to know what’s true,” Kidd said.

Aileen Wu is a research and ideas reporter. Contact her at [email protected], and follow them on Twitter at @aileenwu_.