# Overconfidence in ability to discern cancer misinformation: a conceptual replication and extension

## TL;DR

People who are bad at spotting cancer misinformation are often overconfident in their ability, and this overconfidence is linked to their poor discernment skills, not just a lack of self-awareness.

## Contribution

The study extends the Dunning–Kruger Effect to health misinformation, showing that overconfidence is driven by poor discernment rather than metacognitive failure.

## Key findings

- Overconfidence in discerning cancer misinformation is most common among low-performing individuals.
- Overconfidence correlates with exposure to low-credibility health websites and belief in cancer misinformation.
- Deficits in actual discernment ability, not metacognitive insight, explain the link between overconfidence and harmful behaviors.

## Abstract

This study conducts a conceptual replication and extension of prior research on overconfidence in discerning political misinformation, shifting focus to health. Using data from a national survey of American adults linked to web-browsing records (N=593), we investigated the prevalence and correlates of overconfidence in this domain. Consistent with earlier findings, overconfidence was most pronounced among low-performing individuals, replicating the “Dunning–Kruger Effect.” However, decomposition analyses revealed that the associations between overconfidence and behavioral correlates—exposure to low-credibility health websites and belief in cancer-related misinformation—are primarily accounted for by deficits in actual discernment ability rather than a lack of metacognitive insight. This replication highlights the robustness of the link between poor discernment and behavioral outcomes across domains. These results highlight the need for interventions that improve evaluation skills or address underlying dispositional factors, such as distrust in science and conspiracist worldviews.