We propose another positive illusion that fits with McKay & Dennett's (M&D's) criteria for adaptive misbeliefs. This illusion is pervasive in adult reasoning but we focus on its prevalence in children's developing theories. It is a strongly held conviction arising from normal functioning of the doxastic system that confers adaptive advantage on the individual.

The social environment influences what information individuals sample: people are often exposed to alternatives that are popular. This can systematically change an individual's evaluation of an alternative if she had previously been avoiding it due to a negative evaluation. The authors show that social exposure can have positive or negative effects on evaluation, depending on how popularity and prior evaluations interact. This theory was supported by a large‐scale analysis of data from a hotel chain.

Naive physics beliefs can be systematically mistaken. They provide a useful test-bed because they are common, and also because their existence must rely on some adaptive advantage, within a given context. In the second part of the commentary we also ask questions about when a whole family of misbeliefs should be considered together as a single phenomenon.