New Issue: Science’s Impossible Questions. Read Now

Everyone Agrees

An oft-heard opinion seems popular even if it comes from only one person

Join Our Community of Science Lovers!

With the 2008 presidential election only a year away, the merits of each candidate are becoming a common topic of conversation. But how do our brains, after hearing so many different opinions, gauge the popularity of each one? New research findings suggest that we judge a viewpoint's prevalence by how familiar it is—regardless of whether we have heard it five times from one person or once each from five different people.

Kimberlee Weaver, a psychologist at Virginia Polytechnic University, and her colleagues gave volunteers records of opinions from a fictional focus group that had supposedly met to discuss the preservation of open space in New Jersey. In some cases, multiple people expressed the viewpoints; in others, the same person repeated an opinion many times. Based on these records, they asked the subjects to estimate how the focus group, and the population in general, felt about the matter.

The study participants rated an opinion as popular if it had been expressed several times—even if only one person had said it. The researchers’ follow-up experiments suggested that the opinion's familiarity was the most important factor in whether subjects considered it to be common.


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


“People are not always good at inferring what other people think,” Weaver says. The ability to gauge the sentiment of a crowd is vital for good social decision making, and for the most part evolution has honed our skills of perception. But our psychological mechanisms are sometimes subject to constraints—and this phenomenon is a perfect example. According to Weaver, these types of miscalculations could sway our own opinions and perceptions of reality, leading us to unintentionally make decisions influenced by a mentally amplified vocal minority.

SA Mind Vol 18 Issue 4This article was published with the title “Everyone Agrees” in SA Mind Vol. 18 No. 4 (), p. 13
doi:10.1038/scientificamericanmind0807-13a

Subscribe to Support Independent Journalism

Great science journalism requires human expertise, time, effort and creativity. And it costs money. That’s why I and the journalists here at Scientific American hope you’ll join our community.

When you subscribe, you are supporting staff and freelance journalists who are passionate about telling science stories that are true, important and compelling. Our editors and reporters are often experts in their fields, which means they understand the nuances of big discoveries and can untangle the breakthroughs from the hype. With a subscription, you are also supporting rigorous fact-checking to ensure the words we publish are precise and accurate. And you’re supporting original illustrations, graphics and photos that bring you closer to an advanced laboratory, an ice sheet in Antarctica or a space mission in orbit. You’re helping us craft other types of high-quality journalism as well: Our newsletters are carefully written, edited and curated by staffers you have or will come to know and love. Our Science Quickly podcast is based on original reporting, collaboration with editors and scientists and exacting production.

Subscriptions keep this engine running so we can continue to deliver thoughtful, rigorous and independent science journalism to you. In an era of viral misinformation, this work is crucial. If you value what we do, I hope you’ll consider joining us as a subscriber

Thank you,

Jeanna Bryner, Editor in Chief, Scientific American

Subscribe