Controversial science critics who turn into believers can sway others, research shows

A new study has shown that people who reverse their opinions on the most provocative issues – such as the use of genetically modified crops – can become some of the most influential supporters about scientific facts to the general public.

The researchers found that these ‘conversion messages’ were particularly effective and persuasive because the speaker justified his change of heart, making the argument appear stronger.

Although these messages are likely to be most effective when the audience doesn’t hold a strong belief either way, the team believes that the findings could offer a pivotal insight into new techniques to deliver stronger communications around other, often controversial science issues.

Dr Ben Lyons, from the University of Exeter and who led the study, said: “In this study we examined genetically modified food, but we feel these findings have implications for other controversial scientific issues, especially those where people don’t have ingrained attitudes.

“After completing this study, I’m more optimistic about our ability to change minds on the issues that haven’t been totally polluted by ideology.”

Researchers used a video of a talk by the British environmentalist Mark Lynas about his transformation from an opponent of GM crops to an advocate.

More than 650 participants for the study, based in the US, were shown one of three video clips featuring excerpts from Mr Lynas’ speech at the Oxford Farming Conference.

The researchers found that both clips that featured a conversion message  - Lynas discussing his prior beliefs and why he changed his mind - were more influential than a simple advocacy message in which Lynas explained the benefits of GM crops.

There was no difference in impact between a basic conversion message detailing Lynas’ former and current beliefs about GM crops, and a more elaborate one detailing the reasoning behind the conversion.

Dr Lyons said: “People exposed to the conversion message rather than a simple pro-GM message had a more favourable attitude toward GM foods. The two-sided nature of the conversion message – presenting old beliefs and then refuting them – was more effective than a straightforward argument in favour of GM crops.”

The study, “Conversion messages and attitude change: Strong arguments, not costly signals” is published in the journal Public Understanding of Science and was carried out with Ariel Hasell, a research fellow at the University of Michigan, and Meghnaa Tallapragada, an assistant professor of strategic communication at Clemson University – and APPC Director Kathleen Hall Jamieson.

The research was supported by the Science of Science Communication program of the Annenberg Public Policy Center of the University of Pennsylvania and the European Research Council under the European Union’s Horizon 2020 research and innovation programme.