Children understand subjective (undesirable) desires before they understand subjective (false) beliefs

Our folk psychology is built around the ascription of beliefs (and related cognitive states) and desires (and related conative states). How and when children develop a concept of these different kinds of propositional attitudes has been the subject of a long-standing debate. Asymmetry accounts assume that children develop a conception of desires earlier than they develop a concept of beliefs. In contrast, the symmetry account assumes that conceptions of both kinds of attitudes are based on the same underlying capacity to ascribe subjective perspectives. Accordingly, a genuine subjective understanding of desires develops in tandem with subjective belief understanding. So far, existing evidence that tested these two accounts remains inconclusive, with inconsistent findings resulting from diverging methods. Therefore, the current study tested between the two accounts in a more systematic way. First, we used a particularly clear test case-value-incompatible (wicked) desires. Such desires are strongly subjective because they are desirable only from the agent's perspective but not from an objective perspective. Second, we probed children's ascription of such desires in the most direct and simplified ways. Third, we directly compared children's desire understanding with their ascription of subjective beliefs. Results revealed that young children were better in reasoning about subjective desires than about subjective beliefs. Desire reasoning was not correlated with subjective belief reasoning, and children did not have more difficulties in reasoning about strongly subjective wicked desires than about neutral desires. All in all, these findings are not in line with the predictions of the symmetry account but speak in favor of the asymmetry account.