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.

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.

Focusing on the individual's internal cognitive architecture, McKay & Dennett (M&D) provide an incomplete analysis because they neglect the crucial role played by the external environment in producing misbeliefs and determining whether those misbeliefs are adaptive. In some environments, positive illusions are not adaptive. Further, misbeliefs often arise because the environment commonly fails to provide crucial information needed to form accurate judgments.

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.