Several explanations have been proposed for this pattern of results. First, children’s failure at the last task suggests that keeping the sets visible may have a negative impact on their performance. When sets are visible, children may be drawn to rely on perception, which is approximate, and thus to generalize number words beyond exact numerical quantities. However, this explanation seems MEK inhibitor unlikely, because (1) Condry and Spelke’s (2008) visible single-set task induced major changes in numerosity (doubling and halving), easily detectable by children, and (2) children failed at Sarnecka and Gelman’s (2004) one-to-one comparison task, where the conditions of presentation

highlighted any difference across sets. Second, it is possible that tasks involving two sets are simply overwhelming for children, single-set tasks thus being a better indicator of children’s this website semantic competence (Sarnecka & Gelman, 2004). However, Condry and Spelke (2008) showed that children sometimes succeed in two-set tasks, since participants solved the task with high accuracy when no transformation was applied to the sets, and they also showed that participants sometimes failed in single-set tasks. Third, counter to the previous explanation, Brooks et al. (2012) argued that children succeeded at Sarnecka and Gelman’s (2004) single-set

transformation task without extensive knowledge of the semantics of the number words. According to their argument, to succeed at the task children only need to know that a change in quantity is necessary to warrant a change of number word: therefore, children know to conserve

the initial label after a shaking event. For addition and subtraction transformations, however, they find the right answer only by applying pragmatic inferences: If a child is given a choice between a label he/she heard earlier 4��8C in the trial and a new label, Brooks et al. argue, given the assumption that the adult asking the question is knowledgeable, the child would infer that the new label provided is relevant. Pragmatic inferences, in contrast, provide no ground to find the correct answer in Condry and Spelke’s (2008) two-sets task. To support this view, Brooks et al. adapted Condry and Spelke’s (2008) two-set task and Sarnecka and Gelman’s (2004) single-set transformation task using novel words and objects, and obtained the same pattern of success and failure across these two tasks, where children were asked to choose between two labels (as in Sarnecka and Gelman’s single-set task) or between two objects (as in Condry and Spelke’s two-sets task). This last explanation holds promise to explain the whole set of results, with one adjustment: Given the contrast between children’s reasoning about identity and substitution events in Experiment 4, children may not think that a change in number words requires a change in quantity but rather a change of set identity.