Researchers found that people often use search engines in ways that unintentionally reinforce their existing beliefs. The study, published in the Proceedings of the National Academy of Sciences, shows that even unbiased search engines can lead users into digital echo chambers—simply because of how people phrase their search queries.

"When people look up information online—whether on Google, ChatGPT or new AI-powered search engines—they often pick search terms that reflect what they already believe (sometimes without even realizing it),” said lead author Eugina Leung, an assistant professor at Tulane’s A. B. Freeman School of Business. “Because today’s search algorithms are designed to give you ‘the most relevant’ answers for whatever term you type, those answers can then reinforce what you thought in the first place. This makes it harder for people to discover broader perspectives.”

For example, people who believe caffeine is healthy might search “benefits of caffeine,” while skeptics might type “caffeine health risks.” Those subtle differences steered them toward drastically different search results, ultimately reinforcing their original beliefs.

The effect persisted even when participants had no intention of confirming a bias. In a few studies, fewer than 10% admitted to deliberately crafting their search to validate what they already thought, yet their search behavior still aligned closely with their beliefs.

The researchers tested several ways to encourage users to broaden their views. Simply prompting users to consider alternative perspectives or perform more searches had little effect. However, one approach worked consistently: changing the algorithm.

When search tools were programmed to return a broader range of results—regardless of how narrow the query was—people were more likely to reconsider their beliefs. In one experiment, participants who saw a balanced set of articles about caffeine health effects walked away with more moderate views and were more open to changing their behavior.

Users rated the broader results equally useful and relevant as the narrowly tailored ones. The findings suggest that search platforms could be crucial in combating polarization—if designed to do so. The researchers even found that most people were interested in using a “Search Broadly” feature—a button (conceptualized as doing the opposite of Google’s current “I’m feeling Lucky” button) that would intentionally deliver diverse perspectives on a topic.