Becoming Speciesist: How Children and Adults Differ in Valuing Animals by Species and Cognitive Capacity

Children morally prioritize humans over animals less than adults do. Is this because children are less speciesist-meaning they place less moral weight on mere species membership? Or is it because they give less weight to differences in cognitive capacity between humans and other animals? We investigated this in two experiments, presenting children and adult participants in the United States and Spain with moral trade-off dilemmas. These dilemmas involved individuals who varied in species membership (human vs. monkey) and cognitive capacity. Across both cultures, children were less likely than adults to prioritize humans over animals, regardless of cognitive capacity. In addition, participants tended to prioritize individuals with higher cognitive capacities, regardless of species membership-though this effect was less robust in children. Our findings suggest that children in these Western contexts are indeed less speciesist than adults, though they do not rule out developmental changes in the moral weight assigned to cognitive capacity.