Generic statements (e.g., ''Birds lay eggs'') express generalizations about categories. In this paper, we hypothesized that there is a paradoxical asymmetry at the core of generic meaning, such that these sentences have extremely strong implications but require little evidence to be judged true. Four experiments confirmed the hypothesized asymmetry: Participants interpreted novel generics such as ''Lorches have purple feathers'' as referring to nearly all lorches, but they judged the same novel generics to be true given a wide range of prevalence levels (e.g., even when only 10% or 30% of lorches had purple feathers). A second hypothesis, also confirmed by the results, was that novel generic sentences about dangerous or distinctive properties would be more acceptable than generic sentences that were similar but did not have these connotations. In addition to clarifying important aspects of generics' meaning, these findings are applicable to a range of real-world processes such as stereotyping and political discourse.

One of the most prominent theories for why children struggle to learn verbs is that verb learning requires the abstraction of relations between an object and its action (Gentner, 2003). Two hypotheses suggest how children extract relations to extend a novel verb: (1) seeing many different exemplars allows children to detect the invariant relation between actions in different contexts (Gentner, 2003), and (2) repetition of fewer exemplars allows children to move beyond the entities involved to extract the relation (Kersten & Smith, 2002). We tested 2 1/2- and 3-year-olds' ability to extend a novel verb after viewing the repetition of one novel actor compared to four different actors performing a novel action. Both ages were better at learning and extending a novel verb to a novel actor when shown only one actor rather than four different actors. These results indicate that during initial verb learning less information is more effective.

Children and adults commonly produce more generic noun phrases (e.g., Birds fly) about animals than artifacts. This may reflect differences in participants' generic knowledge about specific animals/ artifacts (e.g., dogs/chairs), or it may reflect a more general distinction. To test this, the current experiments asked adults and preschoolers to generate properties about novel animals and artifacts (Experiment 1: Real animals/artifacts; Experiments 2-3: Matched pairs of maximally similar novel animals/artifacts). Data demonstrate that even without prior knowledge about these items, the likelihood of producing a generic is significantly greater for animals than artifacts. These results leave open the question of whether this pattern is the product of experience and learned associations or instead a set of early-developing theories about animals and artifacts.Generic noun phrases (e.g., Birds fly) have been hypothesized to "provide a window onto human concepts" (Gelman & Tardif, 1998, p. 215). By referring to a category as an abstract whole (birds in general as opposed to any particular bird or birds), generics express generalizations about shared properties of category members. Research demonstrates that both children and adults produce significantly more generics for categories within the domain of animals than for those within the domain of artifacts (e.g., Gelman, Coley, Rosengren, Hartman, & Pappas, 1998;Gelman, Goetz, Sarnecka, & Flukes, 2008;Gelman & Tardif, 1998;Goldin-Meadow, Gelman, & Mylander, 2005). However, why this pattern is found is unclear.Some have proposed that the animacy bias in generics may reflect a broad differentiation between animal and artifact concepts. For example, animal concepts are more likely to be richly structured and essentialized than artifact concepts (e.g., Gelman, 2003). On this view, the greater proportion of generics in conversation regarding animals may reflect fundamental differences in how these concepts are structured. However, one alternative hypothesis is that this bias may instead reflect lower-level differences in children's familiarity with or generic knowledge base about the particular animal versus artifact categories being discussed (e.g., dogs versus chairs): children may simply know more generic information about specific, basiclevel animal kinds than about specific, basic-level artifact kinds. For example, they may have learned numerous generic properties of dogs (e.g., Dogs have fur, four legs, cold noses; Dogs bark, wag their tails, dig for bones, retrieve sticks) but few generic properties of chairs (e.g., Chairs are for sitting; Chairs have legs and a seat). The current experiments aim to test the Correspondence concerning this article should be addressed to Amanda C. Brandone, Department of Psychology, University of Michigan, 530 Church Street, Ann Arbor, MI 48109. Email: Brandone@umich.edu. Publisher's Disclaimer: This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing t...

The ability to interpret and predict the actions of others is crucial to social interaction and to social, cognitive, and linguistic development. The current study provided a strong test of this predictive ability by assessing (1) whether infants are capable of prospectively processing actions that fail to achieve their intended outcome, and (2) how infants respond to events in which their initial predictions are not confirmed. Using eye tracking, 8-month-olds, 10-month-olds, and adults watched an actor repeatedly reach over a barrier to either successfully or unsuccessfully retrieve a ball. Ten-month-olds and adults produced anticipatory looks to the ball, even when the action was unsuccessful and the actor never achieved his goal. Moreover, they revised their initial predictions in response to accumulating evidence of the actor’s failure. Eight-month-olds showed anticipatory looking only after seeing the actor successfully grasp and retrieve the ball. Results support a flexible, prospective social information processing ability that emerges during the first year of life.

When do infants understand that goals exist independently of the actions that result from them? Exploring infants' understanding of failed intentional actions-when the goal of the action is unfulfilled and thus non-apparent in the actor's movements-critically addresses this question. Using a visual habituation paradigm, we assessed when infants understand that a failed intentional action is goal-directed and whether an understanding of successful intentional actions (actions that do overtly attain their goals) precedes an understanding of failed intentional actions. Results demonstrate that 10-and 12-month-olds recognized the goal-directedness of both successful and failed reaching actions. Eight-month-olds also recognized the goal-directedness of successful actions, but failed to do so for unsuccessful attempts. These results show that by the first year of life, infants possess an impressive understanding of intentional action and that an understanding of failed intentional actions follows an earlier understanding of successful ones.A hallmark of human cognition is the ability to transcend information provided by the behavior stream and make inferences about the underlying causes of human action. Indeed, the success of human social interaction rests upon the recognition that people act according to internal mental states such as beliefs, desires, and intentions. An important developmental question is, thus, when do children come to perceive the motions of others as guided by intentions? A critical test for this knowledge is one that involves reasoning about the goal of a failed action. Inferring a goal when it is unfulfilled and thus non-apparent in the actor's movements or the outcome achieved would not be possible without penetrating deeper than the surface appearance of the action. Thus, appreciation of failed action as goal-directed provides firm evidence for understanding that goals exist independently of the particular actions performed. When and how does this understanding develop?Two sets of findings frame this question. First, infants in the second year clearly appreciate the intentions underlying failed actions. The firmest demonstration of this comes from Meltzoff (1995) where, after witnessing an adult try but fail to fulfill several novel, objectdirected goals (e.g., trying to hang a ring on a hook), 18-month-olds read through the actor's bodily movements to the underlying intention of the action. Although infants never saw the actions successfully modeled, when given a chance to act on the objects themselves they "imitated" the successful goal-directed actions much more than the failed (actually witnessed) actions. Replications of these experiments have shown that 15-month-olds (Carpenter et al., 1998) but not 12-month-olds (Bellagamba & Tomasello, 1999) also display