# Metacognition and diagnostic decision-making: short "blips" of knowledge and the consequences of overconfidence

## TL;DR

Brief exposure to medical information can create overconfidence, leading people to stop seeking more information and make poor self-diagnoses.

## Contribution

The study identifies how short-term knowledge exposure leads to overconfidence and reduced information-seeking in diagnostic decisions.

## Key findings

- People are most overconfident after a short period of exposure to medical knowledge.
- Overconfidence is linked to a reduced willingness to seek additional information for diagnosis.
- Brief knowledge exposure can create an illusion of knowing, leading to sub-optimal medical decisions.

## Abstract

When making decisions under uncertainty, we rely on the information we currently have. Presumably, the more information we have, the better our decisions turn out to be. What, though, drives our motivation to seek more information? The current research investigated people's confidence judgments in one's current information and their relationship to seeking more information when making diagnoses when presented with a sequence of medical symptoms. In Experiment 1, we explored people’s confidence judgments in relation to the accumulation of information they received. In Experiment 2, we tested whether a participant’s confidence levels would guide the decision to seek more information. The results showed that (1) people had the most overconfidence with a short period of exposure to medical knowledge (as opposed to a long period or none at all) and (2) that overconfidence was associated with choosing not to seek more information. In short, a "blip of knowledge" can lead to an illusion of knowing, which, in turn, could lead to a sub-optimal decision when it comes to medical diagnosing.

The online version contains supplementary material available at 10.1186/s41235-026-00717-x.

This study demonstrates that brief exposure to medical information, or a "blip of knowledge," can lead to overconfidence in self-diagnosis, discouraging individuals from seeking additional information. By identifying this cognitive bias and exploring various factors that may influence it, the research provides a foundation for future studies and insights that can help improve decision-making practices and, in the long run, even contribute to better public health outcomes. Imagine waking up one morning with a slight scratch in your throat. You briefly consider calling a doctor, but as a cough develops you reassure yourself that “a cold is going around” and decide that it is probably just a common cold. Most people can relate to such scenarios: when new symptoms appear, we often make an initial judgment about their cause and whether professional help is necessary. In these moments, we act as our own diagnosticians, relying on whatever knowledge we currently have. Diagnostic decisions are a particularly consequential form of decision-making under uncertainty. One incorrect decision can have serious implications, including, in the extreme, for morbidity, mortality, and quality of life (Berner & Graber, 2008; Croskerry & Norman, 2008). Although it is impossible to guarantee that every diagnosis is correct, having more relevant information before committing to a diagnosis should, in principle, improve decisions. Yet both clinicians and people frequently stop information search prematurely, sometimes after only a brief exposure to medical information—such as reading a short online article, scanning a search-engine result, or consulting a symptom checker (Bertolazzi et al., 2023; Ceney et al., 2021). The present research examines how such brief exposures to medical knowledge shape people’s confidence in their diagnostic judgments, the accuracy of those judgments, and their willingness to seek additional information. From a metacognitive perspective, these decisions depend not only on what people know but also on how they monitor and control their knowledge (Koriat, 2012). People must assess how certain they are about a possible diagnosis, and then decide whether their current confidence justifies acting on that diagnosis or whether more information should be gathered. A central concern in this process is overconfidence— a miscalibration between subjective confidence and objective accuracy.

The online version contains supplementary material available at 10.1186/s41235-026-00717-x.