Hugo Mercier

Research focused on the United States shows that people’s trust in science varies considerably between disciplines. Existing explanations of these trust gaps stress the role of ideology: when people perceive scientists of a particular discipline to be ideologically like-minded, they tend to trust them more. Here, we report two findings: first, trust gaps between disciplines also exist in France—a representative sample of the French population (N = 1012) trusted researchers in biology and physics more than researchers studying climate science, economics, or sociology. Second, the more precise and consensual participants perceive scientific findings to be, the more they tend to trust the scientists (across and within disciplines). While these findings are correlational, they align with a non-ideological explanation of trust in science: the rational impression account. This account proposes that people can come to trust scientists by relying on basic cognitive inference processes, which tend to be generally rational.

What are the distinctive characteristics of misinformation sharers? So far, most studies have focused on the U.S., a two-party system with a highly polarized media landscape, leaving open the question of what misinformation sharers look like in other socio-political contexts. Research has also prioritized testing causal links between cognitive or political variables and misinformation sharing, while paying less attention to fine-grained descriptions of who these users are. To address this gap, we analyze the French Twittersphere using ideological inference methods and a matching procedure. Drawing on four million tweets, we compare 1,907 users who shared at least one URL flagged as false or misleading by fact-checkers with 958 ideologically matched control users who did not. We show that misinformation sharers are more likely to be located at the extremes of the political spectrum, express hostility toward ruling elites and institutions, display political markers in their bios, use pseudonyms, share media content, engage in high-intensity and retweet-oriented activity, and express negative emotions. They also disproportionately circulate topics related to immigration, terrorism, and criticism of mainstream media. However, their language does not indicate lower analytical thinking. By shifting the focus from cognitive vulnerability alone to political self-presentation, anger, and amplification practices, this study contributes to ongoing theoretical debates and calls for further research on the activist practices and party affiliations of misinformation sharers.

Over the past three decades, psychology has documented the recurrence of specific themes in stories across cultures (e.g., love, alliances, monsters, imaginary worlds) and linked them to identifiable motivational mechanisms (e.g., mate choice, cooperation, threat detection, exploration). Yet this body of work has remained fragmented, organized around individual themes rather than integrated into a unified account of what makes narrative content psychologically engaging. Here, we propose the Motivational-Ingredient Framework. We identify a set of motivational ingredients: core narrative features, each defined by the specific motivational mechanism it activates. Drawing on evolutionary psychology, affective neuroscience, and the study of human motivation, we compile a comprehensive table of ingredients grounded in the current understanding of human motivational architecture. This framework offers a theory-driven, cross-culturally applicable foundation for the empirical study of narrative content, with implications for fields ranging from media psychology and computational humanities to education and public policy.

Seeing someone endorse a conspiracy theory could be informative of which other conspiracy theories they might endorse and reveal broader personality traits. Across three pre-registered experiments (N = 775 US participants), we show that these inferences are supported by the nested structure of conspiracy beliefs: individuals who endorse less popular theories tend to endorse more popular ones, but not vice versa. This pattern holds for real-world conspiracy theories (false and true) as well as for invented ones. When presented with the information that someone endorses or rejects a conspiracy theory, participants could predict which other theories that individual would endorse or reject. Moreover, participants could infer the personality traits of conspiracy believers (e.g., narcissism, manichaeism) by appropriately weighing the rarity of the endorsed conspiracy theory. These findings suggest that people use a folk theory of latent conspiracism to draw broadly accurate inferences about conspiracy believers (or non-believers) from limited information.

People routinely infer others' competence under uncertainty, often relying on cues such as task difficulty and past accuracy. An emerging body of research suggests that people approximate Bayesian inference when doing so. We extend these results by testing whether people can infer others' numerical ability in a way that is consistent with a rational Bayesian model. In Study 1, we find that participants accurately predict the arithmetic performance of another individual from information about their past performance. Computational modeling shows that participants' inferences are better described by Bayesian processes than by plausible heuristics. Study 2 introduces a modified paradigm, in which participants are told about both past performance and time taken to solve problems. We find that, although participants are quite accurate in their predictions, they do not seem to take into account information about speed.

The reporting of the sources of our statements—whether we have, e.g., seen something or been told something—plays an important role in communication. The inaccurate reporting of sources is often associated with the spread of inaccurate beliefs, as when rumors are attributed to a non-existent credible source. Experiments have revealed that participants display a substantial amount of flexibility in the reporting of sources, in particular by attributing to themselves ideas they have acquired from others. However, these participants belonged to large-scale societies, and they spoke languages without grammatical evidential marking. Both factors might increase flexibility in source reporting. To test whether members of small-scale societies speaking languages with evidential marking also display flexibility in source reporting, we conducted two experiments with Quichua and Cha’palaa speakers in Ecuador. In both experiments, some participants acquired a belief through social transmission, and then had to communicate this belief to another participant. In doing so, very few participants mentioned the social source of their belief, whether explicitly, or by using the relevant evidential markers. These results show that flexibility in source reporting is a cross-culturally robust phenomenon, and that grammatical evidential marking does not appear to strongly affect this flexibility.

We agree with Ecker et al. (2025) that misinformation should not be ignored. The specific form that misbeliefs take is indeed shaped by misinformation (e.g., vaccines cause autism). However, this does not imply that misinformation causes behaviors (e.g., vaccine refusal). We view misinformation as a symptom of deeper problems. When many are willing to consume, believe, and act on misinformation, this is diagnostic of broader sociopolitical issues-such as polarization or widespread mistrust-that make misinformation appealing rather than misinformation causing these issues. In particular, we consider that attitudinal and structural roots explain both the consumption and acceptance of misinformation, on the one hand, and the behaviors ascribed to misinformation on the other. (PsycInfo Database Record (c) 2026 APA, all rights reserved).