Is biology destiny? The coherence of children’s beliefs about physical and psychological traits

In adults, biological causes are commonly associated with immutability. However, it remains unclear when during their development children coherently connect these ideas in relation to reasoning about physical and mental traits and whether children reason differently by domain. Understanding this is relevant to illuminating children’s conceptions about the body versus the mind. Prior work has suggested that a more sophisticated differentiated understanding of psychological traits may begin to emerge around 8 years of age. In Study 1a, therefore, we examined U.S. third graders’ reasoning about the inheritance and malleability of physical and mental traits and whether their ideas coherently covary within each domain. In Study 1b, we further investigated the robustness of this differentiated understanding by exploring whether participating in a curriculum that presented simplified information about physical traits affected thinking about mental traits. Results reveal that third graders display robust coherence in their reasoning about trait inheritance and malleability. Children consistently judged physical traits as more inherited and less malleable than mental traits, with children’s ideas about inheritability and malleability showing consistent connections within each domain. Moreover, exposure to science teaching about physical traits did not alter children’s perception that mental traits are less inherited and more malleable. By 8 years of age, therefore, children clearly distinguish body from mind in theoretically coherent ways. Nevertheless, the covariance between beliefs about inheritability and immutability should provoke caution when talking to children about parent–child resemblances in capacities like intelligence lest some children infer that their abilities cannot be improved through effort.