Comparative judgments for mass and count nouns yield two generalizations. First, all words that can be used in both mass and count syntax always denote individuals when used in count syntax but never when used in mass syntax. Second, some mass nouns denote individuals while others do not. In this article, we show that no current theory of mass–count semantics can capture these two facts and argue for an alternative theory that can. We propose that lexical roots are not specified (...) as mass or count. Rather, a root becomes a mass noun or count noun by combining with a functional head. Some roots have denotations with individuals while others do not. The count head is interpreted as a function that maps denotations without individuals to those with individuals. The mass head is interpreted as an identity function making the interpretation of a mass noun equivalent to the interpretation of the root. As a result, all count nouns have individuals in their denotation, whereas mass counterparts of count nouns do not. Also, some roots that have individuals in their denotations can be used as mass nouns to denote individuals. (shrink)

People frequently gesture when problem-solving, particularly on tasks that require spatial transformation. Gesture often facilitates task performance by interacting with internal mental representations, but how this process works is not well understood. We investigated this question by exploring the case of mental abacus, a technique in which users not only imagine moving beads on an abacus to compute sums, but also produce movements in gestures that accompany the calculations. Because the content of MA is transparent and readily manipulated, the task (...) offers a unique window onto how gestures interface with mental representations. We find that the size and number of MA gestures reflect the length and difficulty of math problems. Also, by selectively interfering with aspects of gesture, we find that participants perform significantly worse on MA under motor interference, but that perceptual feedback is not critical for success on the task. We conclude that premotor processes involved in the planning of gestures are critical to mental representation in MA. (shrink)

Reasoning about ulterior motives was investigated among children ages 6–10 years (total N = 119). In each of two studies, participants were told about children who offered gifts to peers who needed help. Each giver chose to present a gift in either a public setting, which is consistent with having an ulterior motive to enhance one's reputation, or in a private setting, which is not consistent with having an ulterior motive. In each study, the 6- to 7-year olds showed no (...) evidence of understanding that the public givers might have ulterior motives, but the 8- to 10-year olds rated the private givers more favorably. In , the older children were more likely than the younger children to refer to impression management when explaining their judgments of the givers. The younger children who mentioned impression management did so to justify a preference for public givers (e.g., by explaining that public givers are nicer because more of their peers will know that they are nice). Results from suggest that developmental change in children's reasoning about intentions and social outcomes contributes to their understanding of ulterior motives. (shrink)

Preschoolers often struggle to compute scalar implicatures involving disjunction, in which they are required to strengthen an utterance by negating stronger alternatives, e.g. to infer that, ‘The girl has an apple or an orange’ likely means she does not have both. However, recent reports surprisingly find that a substantial subset of children interpret disjunction as conjunction, concluding instead that the girl must have both fruits. According to these studies, children arrive at conjunctive readings not because they have a non-adult-like semantics, (...) but because they lack access to the stronger scalar alternative and, and employ doubly exhaustified disjuncts when computing implicatures. Using stimuli modelled on previous studies, we test English-speaking preschoolers and replicate the finding that many children interpret or conjunctively. However, we speculate that conditions which replicate this finding may be pragmatically infelicitous, such that results do not offer a valid test of children’s semantic competence. We show that when disjunctive statements are uttered in contexts that render the speaker’s intended question more transparent, conjunctive readings disappear almost entirely. (shrink)

Children’s difficulty deriving scalar implicatures has been attributed to a variety of factors including processing limitations, an inability to access scalar alternatives, and pragmatic tolerance. The present research explores the nature of children’s difficulty by investigating a previously unexplored kind of inference—an exhaustivity implicature that is triggered by disjunction. We reasoned that if children are able to draw quantity implicatures but have difficulties accessing alternative lexical expressions from a scale, then they should perform better on exhaustivity implicatures than on scalar (...) implicatures, since the former do not require spontaneously accessing relevant scalar alternatives from the lexicon. We conducted two experiments. Experiment 1 found that 4- to 5-year-olds consistently computed exhaustivity implicatures to a greater extent than scalar implicatures. Experiment 2 demonstrated that children are more likely to compute exhaustivity implicatures with disjunction compared to conjunction. We conclude that children often fail to derive scalar implicatures because they struggle to access scalar alternatives and disjunction makes subdomain alternatives particularly salient. Thus, the findings suggest that exhaustivity implicatures can be derived without reference to a scale of alternatives. (shrink)

Though there are holes in the theory of how children move through stages of numerical competence, the current approach offers the most promising avenue for characterizing changes in competence as children confront new mathematical concepts. Like the science of mathematics, children's discovery of number is rooted in intuitions about sets, and not purely in analytic truths.