"Are you a geek like my mom, or do you like to party?" Explanatory bias may precede belief in causal essence

Psychological essentialism is the widespread belief that members of natural and social categories share deep, physical properties, or “essences,” that cause their common observable characteristics, as well as their identity as category members (e.g., a Chihuahua “essence” causes it to be Chihuahua). The tendency to essentialize is pervasive; it has been documented in children and adults, as well as a number of different cultures (see Gelman, 2003, for a review). However, there is still much to learn about the development of essentialism. What are the origins of essentialist thought? This question remains challenging to answer, particularly because researchers have yet to determine a precise way to measure the belief in a causally powerful essence. The present research had two goals: 1) to refine and validate essentialism measures in order to more accurately capture the belief in a causal essence, and 2) to use these measures to test a possible precursor to essentialist reasoning as a step toward uncovering the origins of essentialist thought. In Study 1, I adapted measures from the essentialism literature that seemed to best capture the belief in a causally powerful essence. I refined these measures to develop a more precise test of essentialist beliefs. The findings from this study adequately validate my revised measures: 5- to 7-year-old children and adults show developmentally normative essentialist beliefs, in line with previous work. These measures may be useful for researchers interested in examining essentialist beliefs in young children. In Studies 2 and 3, I tested a possible precursor to essentialist beliefs—namely the domain-general bias to explain via inherent information (Cimpian & Salomon, 2014). Previous work shows that essentialist beliefs do not emerge until the age of four. Thus, if inherent thinking is a precursor to essentialism, it should be present before essentialism, perhaps at age three. Using my revised measures, I tested the presence of essentialism and inherent thinking in three-year-old children. My findings indicate that three-year-old children have yet to develop the belief in a causal essence. However, these children do show early signs of inherent thinking. Overall, these studies suggest that a bias in explanation (i.e., the inherence heuristic) may precede essentialism. This research takes us one step closer toward understanding the developmental course of essentialist beliefs