It has been suggested that due to functional similarity, sortal object individuation might be a primordial form of psychological essentialism. For example, the relative independence of identity judgment from perceived surface features is a characteristic of essentialist reasoning. Also, infants engaging in sortal object individuation pay more attention to kind than surface feature information when judging the identity of objects (e.g.). Indeed, previous research found that 14-month-old infants can judge trans-temporal identity even in complete absence of kind-specific surface features. Here, we used another more demanding non-linguistic paradigm to test the limits of these abilities in 14-, 18-, 23- and 36-month-old infants, comparing their performance to recent great ape data. Particularly, we presented infants with two food kinds, whose surface features were then fully transformed to make them look identical. If reasoning according to essentialist principles, participants should select the preferred item despite superficial manipulations. However, only 36-month-olds reliably tracked the preferred item after superficial manipulations. This suggests that, although basic psychological essentialism may emerge early in infancy, more complex forms require domain-general cognitive prerequisites, which only develop in more protracted form.

已经提出，由于功能上的相似性，分类对象的个体化可能是心理本质主义的原始形式。例如，身份判断与感知的表面特征的相对独立性是本质论推理的特征。而且，在判断物体（例如）的身份时，从事分类物体个性化的婴儿比表面特征信息更注重种类。确实，先前的研究发现，即使完全没有种类特异性的表面特征，14个月大的婴儿也可以判断跨时间身份。在这里，我们使用了另一个要求更高的非语言范式来测试14、18、23和36个月大婴儿的这些能力的极限，并将其表现与最近的大猿猴数据进行比较。特别是，我们为婴儿提供了两种食物，然后对其表面特征进行完全转换以使其外观相同。如果根据本质主义原理进行推理，则尽管进行了表面操作，参与者仍应选择首选项目。但是，只有36个月大的孩子在进行了表面操作之后便可靠地跟踪了该首选物品。这表明，尽管基本的心理本质主义可能会在婴儿期早期出现，但更复杂的形式则需要领域通用的认知前提，而前提是认知形式的发展会更加持久。