How people update their beliefs about climate change: An experimental investigation of the optimistic update bias and how to reduce it

People usually update their beliefs selectively in response to good news and disregard bad news. Here, we investigated in two preregistered experiments (N = 278 and N = 306) (1) whether such valence-dependent belief updating also underlies information processing in the context of climate change and (2) whether it can be altered by interventions informing about different aspects of climate change. To this end, we adapted a well-established belief update task to the context of climate change. In multiple trials, participants were asked about their beliefs about adverse consequences of climate change; subsequently, they were asked to update their beliefs in light of new information. Both studies provided evidence against the hypothesis that people integrate good news about climate change more than bad news. After half of the trials, participants were randomized to one of four video-based interventions, each of which aimed at promoting a more accurate risk perception and increasing pro-environmental intentions. After the interventions, participants showed a more accurate risk perception, and women rather than men increased their intentions for pro-environmental behavior. The results provide implications for climate change communication, as they show that when facing the consequences of climate change, people adjust their risk perception accurately and increase their pro-environmental intentions.