Original title: Simpler is better for everyone: causal diagram complexity and the role of perceived knowledge in health decisions
Greta Mohr, Samantha Kleinberg · September 2026
Health choices are tough when medical information feels messy and overwhelming. Many tools use causal diagramsPictures that show how one thing (like smoking) can cause another (like diabetes).—simple visual maps showing how health risks, daily actions, and illnesses connect—to guide people. Researchers tested whether making these visual maps more complex helps or hurts choices about Type 2 diabetes. They showed people diagrams with different amounts of detail and checked their decisions. The researchers discovered that looking at any causal diagram led to better choices than looking at no diagram at all. However, as the maps grew more complex, people made worse choices. The team also looked at confidence. People who rated their own diabetes knowledge highly did not make more accurate choices. In fact, having personal experience with diabetes was linked to overestimating knowledge and making worse decisions. Overall, visual health guides work best when they stay simple and concise, especially for people who feel most confident.
Imagine you are trying to fix a leaky faucet. You look up a guide with many detailed steps and diagrams showing every possible pipe connection. The more complex the guide, the more confused you get, and you might end up making the leak worse. In this paper, health diagrams work the same way: simple diagrams help people make better decisions, but complex ones can lead to worse outcomes than having no guide at all.
Doctors and health apps often provide detailed diagrams to explain risk factors. This study shows that too much detail can backfire, making people less accurate in their decisions. Simpler diagrams work better, especially for those who think they know more than they do.
The abstract doesn't state limitations explicitly, but it only studied Type 2 diabetes in an online experiment with US adults, and the causal diagrams were artificial. The results may not generalize to other health conditions or real-world decision aids.
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Simpler is better for everyone: causal diagram complexity and the role of perceived knowledge in health decisions — Greta Mohr, Samantha Kleinberg — Cognitive Research Principles and Implications — doi:10.1186/s41235-026-00756-4
Abstract licence: CC BY
Explanation generated by Synthesis from the abstract — it is not the original paper.