The Dunning-Kruger effect and the muesli bar: Those who know the least tend to believe they are highly competent

The Dunning-Kruger effect can be observed in many different areas: Those who know the least often think of themselves as particularly competent, while those with a lot of knowledge tend to underestimate their own expertise. A research team recently investigated the extent to which this phenomenon can be observed in the area of media and nutrition. The results are clear: Even when it comes to evaluating a supposedly healthy low-carb bar, people who are not competent at all consider themselves to be particularly competent.

Rebecca Scheiber, Matthias Karmasin and Sandra Diehl (all from the Department of Media and Communications at the University of Klagenfurt) surveyed one thousand people representing the Austrian population. The study participants were shown a fictitious advert for a supposedly healthy chocolate muesli bar. While the ad boasted “protein” and “low carb”, it was up to the study participants to estimate the nutritional values.

The results were unequivocal: The Dunning-Kruger effect applies to both. Respondents who had the most limited knowledge of the potentially misleading advertising strategies used to market an unhealthy product as healthy and the actual nutritional values of an advertised muesli bar were most likely to overestimate their own food and media literacy. The reverse effect was also confirmed.

“The problem is this: Those with a low level of knowledge also tend to be active social media users”, Rebecca Scheiber explains. This may result in their inaccurate knowledge being spread through these channels more easily. However, other findings from the study reveal a more optimistic picture, as Scheiber continues: “The well-informed are also often seen as opinion leaders, which means that they can use their knowledge to positively influence others.”

The insights gained are highly relevant for decision-makers in health communication: “Not only do we need more education about misleading advertising and nutritional values of food, but we also need a greater understanding of the Dunning-Kruger effect. People should be aware that their self-assessment may be flawed.” In this case, the effect is particularly insidious for consumers, Scheiber continues: “Consumers who have the least skills but high confidence in their abilities are the most susceptible to misleading food advertising, as they are less wary and more willing to buy the product without being aware of the potentially negative effects of the item.”

The research team recommends that health communication campaigns should be aware of these effects and should address them accordingly. Ultimately, however, we need stricter legal regulations, especially when it comes to food labelling, as consumers’ self-assessments are flawed and inaccurate.

Scheiber, R., Karmasin, M. & Diehl, S. (2023). Exploring the Dunning-Kruger Effect in Health Communication: How Perceived Food and Media Literacy and Actual Knowledge Drift Apart When Evaluating Misleading Food Advertising. Journal of Health Communication, 2023 Nov 2;28(11):707-727. doi: 10.1080/10810730.2023.2258085.