Are we all being misled? New research exposes how repeated information warps our decisions

By Georgie Gould

Imagine the decisions you make every day, such as what to buy, who to trust, or who to vote for, are heavily influenced by a simple yet powerful flaw in your reasoning. Economists at the University of Surrey argue that people are systematically deceived by repeated information, leading to irrational decisions.

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Researchers have identified a surprising cognitive bias that challenges long-standing beliefs about rational decision-making. Their work shows that when individuals come across the same piece of information multiple times, they tend to give it undue weight, making decisions that defy logical norms. This phenomenon isn't just a quirk of human psychology—it's a fundamental flaw that could have wide-ranging implications for everything from marketing to political campaigns.

Dr Umberto Garfagnini, co-author of the study and Senior Lecturer in Economics at the University of Surrey, said:

"This research challenges the idea that people process information rationally. We found that repetition of information–whether it's the same statistic repeated or a message echoed across different platforms–causes people to overestimate its importance, leading them to make choices that are, frankly, irrational."

Over 200 participants were presented with simple decision-making tasks, where they had to update their beliefs based on numerical information. Unknown to them, some of the information was intentionally repeated.

The research team designed experiments exposing participants to repeated numerical information. By comparing how people updated their beliefs with and without repeated information, the researchers were able to pinpoint the specific effects of the repetition.

The results found that: participants consistently treated repeated information as though it was new, skewing their decisions in ways that should not have occurred if they were following traditional, logical rules of thought.

Dr David Walker-Jones, co-author of the study and Lecturer in Economics at the University of Surrey, said:

"In a world where media saturation is the norm, and the same headlines are repeated across platforms, this cognitive bias could be exploited to influence public opinion or consumer behaviour. Our findings suggest that strategies like repeating key messages in advertising or political campaigns might be more effective and manipulative than previously thought."

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