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Humans and nonhuman animals appear to share a capacity for nonverbal quantity representations. But what are the limits of these abilities? Results of previous research with human infants suggest that the ontological status of an entity as an object or a substance affects infants' ability to quantify it. We ask whether the same is true for another primate species-the New World monkey Cebus apella. We tested capuchin monkeys' ability to select the greater of two quantities of either discrete objects or a nonsolid substance. Participants performed above chance with both objects (Experiment 1) and substances (Experiment 2); in both cases, the observed performance was ratio dependent. This finding suggests that capuchins quantify objects and substances similarly and do so via analog magnitude representations.

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Three studies compared beliefs about natural and late blooming positive traits with those acquired through personal effort, extrinsic rewards or medicine. Young children (5-6 years), older children (8-13 years), and adults all showed a strong bias for natural and late blooming traits over acquired traits. All age groups, except 8- to 10-year-olds, treated natural and late-blooming traits as fixed essences that would persist over time and under challenging conditions. Older children and adults viewed traits acquired by intrinsic effort as more similar to natural and late-blooming traits than those acquired through bribes or medicine, suggesting that intrinsic effort itself comes to be seen as a more natural mechanism of change. A bias for the natural may therefore be an early emerging way of evaluating others that is reinforced by the ambient culture and becomes stronger with increasing age.