M Tomasello

..Human morality arose evolutionarily as a set of skills and motives for cooperating with others, and the ontogeny of these skills and motives unfolds in part naturally and in part as a result of sociocultural contexts and interactions...

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..The framework of an alternative, usage-based theory of child language acquisition - relying explicitly on new models from Cognitive-Functional Linguistics - is presented...

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..The developmental outcome is children's ability to construct dialogic cognitive representations, which enable them to participate in earnest in the collectivity that is human cognition...

..Although difficult, with appropriate methodological care, experimental cross-species comparisons may be validly made...

..Implications of these results for various issues in the study of child language acquisition are discussed...

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..g., joint intentions and attention with others). Children's early linguistic skills are built on this already existing platform of prelinguistic communication...

..We conclude by highlighting the role that shared intentionality may play in integrating more biologically based and more culturally based theories of human development...

..This form of collaborative interaction is underlain by species-unique skills and motivations for shared intentionality that make possible, ultimately, such things as complex cultural institutions...

..Infants at both ages did this successfully, lending support to the hypothesis that 1-year-old infants possess a genuine understanding of other persons as intentional and attentional agents...

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..By 3 years of age, children thus recognize both when an adult is committed and when they themselves are committed to a joint activity...

..Great apes' perspective-taking skills seem to have increased in the evolutionary lineage leading to bonobos, chimpanzees, and humans...

..5-year-olds passed. Our study constitutes the first direct investigation of appearance-reality understanding in chimpanzees and the first cross-species comparison of this capacity...

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..Our conclusion for the moment is, thus, that chimpanzees understand others in terms of a perception-goal psychology, as opposed to a full-fledged, human-like belief-desire psychology...

..Chimpanzees can determine the inferences that a conspecific is likely to make and then adjust their competitive strategies accordingly...

..Thus, with an improved methodology we failed to reproduce the findings of Brosnan et al. [Proceedings of the Royal Society of London. Series B. Biological Sciences 272:253-258, 2005] that apes show inequity aversion...

..e. single actions) of this complex skill may be owing to social learning, at the program level gorilla nettle feeding derives mostly from genetic predispositions and individual learning of plant affordances...

..However, there was little evidence that infants used their vocalizations to direct attention to their gestures when the recipient was not attending to them...

..In combination with other studies, these results suggest that to know what others have experienced 14-month-old infants must do more than just perceive others perceiving something; they must engage with them actively in joint engagement...

..These findings suggest that great apes understand both the directedness and the valence of some human emotional expressions, and can use this understanding to infer desires...

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..They did not learn the nonce verb in any condition. These results suggest that from early in linguistic development, young children understand that prosodic salience in a sentence indicates referential newness...

..These results are discussed in terms of the prerequisite cognitive and motivational skills and propensities underlying social behavior...

..Only some apes thus show an understanding of others' intentions as rational choices of action plans...

..Children's prosocial behavior was thus mediated by the intentions behind the actor's moral behavior, irrespective of outcome. Children thus selectively avoid helping those who cause--or even intend to cause--others harm...

..Together, these unique processes of social learning and cooperation lead to humans' unique form of cumulative cultural evolution...

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..Thus, using an inferential action methodology, these studies provide early and particularly convincing evidence that children can track the multiple pretend identities of objects...

..Results for 16-month-olds were in the same direction but less clear. These results represent by far the youngest age of false belief understanding in a task with an active behavioral measure...

..Very young children can sympathize with a victim even in the absence of overt emotional signals, possibly by some form of affective perspective taking...

..Infants just beginning to learn language thus already show a complex understanding of the pragmatics of cooperative communication in which shared experience with particular individuals plays a crucial role...

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..These species differences support the role of ecological and socio-ecological pressures in shaping cognitive skills over relatively short periods of evolutionary time...

..This so-called overjustification effect suggests that even the earliest helping behaviors of young children are intrinsically motivated and that socialization practices involving extrinsic rewards can undermine this tendency...

..These results support the hypothesis that other-regarding preferences and aversion to inequitable outcomes, which play key roles in human social organization, distinguish us from our closest living relatives...

..These results indicate that chimpanzees share crucial aspects of altruism with humans, suggesting that the roots of human altruism may go deeper than previous experimental evidence suggested...

..Children opened the box themselves more often in each of these three conditions than in the two No Prior Intention conditions, even though children in all five conditions saw the exact same demonstration of how to open the box...

..These results suggest that chimpanzees can, in some circumstances, actively manipulate the visual and auditory perception of others by concealing information from them...

..These results are interpreted as evidence for a uniquely human form of cooperative activity involving shared intentionality that emerges in the second year of life...

..The main result across all studies was that chimpanzees made their choices based solely on personal gain, with no regard for the outcomes of a conspecific. These results raise questions about the origins of human cooperative behaviour...

..This result is discussed in terms of apes' adaptations for complex, extractive foraging and dogs' adaptations, during the domestication process, for cooperative communication with humans...

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..These results support the hypothesis that great apes do not just orient to a target that another is oriented to, but they actually attempt to take the visual perspective of the other...

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..Results suggest that 12-month-olds point declaratively and understand that others have psychological states that can be directed and shared...

..experimenter These data together with other recent studies on chimpanzees' knowledge about others' visual perception show that chimpanzees know more about the intentional actions and perceptions of others than previously demonstrated..

..These observations are discussed in the context of siamang ecology, social structure, and cognition...

..The possibility of assigning Seyfarth and Cheney's [1997] model for nonhuman primate vocal development to the development of nonhuman primate gestural communication is discussed...

..Success in the Informing condition requires subjects to understand a cooperative communicative motive - which apparently apes and young infants find difficult...

..The most plausible explanation for these results is the food expectation hypothesis - seeing another individual receive high-quality food creates the expectation of receiving the same food oneself - and not inequity aversion...

..These findings are discussed in the light of recent debates about children's developing understanding of pretense and theory of mind...

..Results suggested that the chimpanzees did not take what the competitor had heard into account, despite being able to locate the hiding place themselves by the noise...

..These results suggest that by twelve months of age infant declarative pointing is a full communicative act aimed at sharing with others both attention to a referent and a specific attitude about that referent...

..Enculturated chimpanzees thus have some understanding of the rationality of others' intentional actions, and use this understanding when imitating others...

..Thus, great apes were able to use a variety of experimenter-given cues associated with foraging actions to locate hidden food and thereby were partially sensitive to the general purpose underlying these actions...

..Differences in spatial arrangement may therefore account for the conflicting results of past studies...

..Differences from and similarities to the other African ape species are discussed...

..Implications of these findings for sign language development, receptive signed vocabulary tests, and the development of the ability to interpret iconic symbols are discussed...

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..They also add to growing evidence that 12-month-olds have some understanding of the looking behaviors of others as an act of seeing...

..The findings of the 3 studies demonstrate that by 2 to 3 years of age, children have a concept of pretense as a specific type of intentional activity...

..Results are discussed in terms of domestic dogs' social-cognitive skills and their unique evolutionary and ontogenetic histories...

..These findings suggest that during the process of domestication, dogs have been selected for a set of social-cognitive abilities that enable them to communicate with humans in unique ways...

..These studies demonstrate in a particularly strong way that even very young children have some grasp of the normative structure of conventional activities...

..The implications of these findings for blocking and other accounts of OR are discussed...

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..We argue that German relative clauses develop in an incremental fashion from simple non-embedded sentences that gradually evolve into complex sentence constructions...

..These findings provide strong support for a mentalistic and prosocial interpretation of infants' prelinguistic communication...

..We argue, finally, that regular participation in cooperative, cultural interactions during ontogeny leads children to construct uniquely powerful forms of perspectival cognitive representation...

..This requires both an understanding of others' goals and an altruistic motivation to help. In addition, we demonstrate similar though less robust skills and motivations in three young chimpanzees...

..Four-year-olds additionally demonstrated learning effects in a transfer task. These results suggest that young children's communication skills develop best in response to feedback about their own attempts at reference...

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..Children at all three ages successfully used both types of cues. We conclude that infants as young as 14 months of age can, in some situations, interpret an adult behaviour as a relevant communicative act done for them...

..The study of convergent evolution provides an exciting opportunity to gain further insights into the evolutionary processes leading to human-like forms of cooperation and communication...

..Like humans, chimpanzees retaliate against personally harmful actions, but unlike humans, they are indifferent to simply personally disadvantageous outcomes and are therefore not spiteful...