Everything has a limit: How intellectual humility lowers the preference for naturalness as reflected in drug choice.

Objective: Across a broad range of cultures, people demonstrate a strong preference for items that are labeled as natural. Yet, less is known about methods that can reduce the natural-is-better bias. The objective of the present research is to see whether intellectual humility, a moral virtue that can be understood as a more open and curious mindset, reduces naturalness bias in terms of drug-related decisions.

Methods: We tested our hypotheses across four studies using different populations (university students and community adults) and methods (correlational and experimental). Study 1 involved a survey exploring whether university students choosing a synthetic drug tended to display a higher level of intellectual humility than those choosing a natural drug. Study 2 assessed the link using observation of real-world behavior in non-student adults. Study 3 adopted an experimental approach to test the idea that reflecting on one's intellectual fallibility can at least temporarily reduce naturalness bias on drug choice. Study 4 examined the potential mediating mechanism underlying the observed effect.

Results: We found correlational and experimental evidence that participants higher in intellectual humility were more likely to choose the synthetic drug than those lower in intellectual humility in both self-report and behavioral measures. The results also demonstrate that openness to experience mediated the effect of intellectual humility on naturalness bias.

Conclusions: These results highlight intellectual humility as a malleable, psychological variable that can combat biased thinking associated with health-related decision-making.