Neonates prefer human speech to other non-linguistic auditory stimuli. However, it remains an open question whether there are any conceptual consequences of words on object categorization in infants younger than 6 months. The current study examined the influence of words and tones on object categorization in forty-six 3-to 4-month-old infants. Infants were familiarized to different exemplars of a category accompanied by either a labeling phrase or a tone sequence. In test, infants viewed novel and new within-category exemplars. Infants who heard labeling phrases provided evidence of categorization at test while infants who heard tone sequences did not, suggesting that infants as young as three months of age treat words and tones differently vis a vis object categorization.Questions concerning the relation between linguistic and conceptual organization hold a central position in the cognitive sciences. Most of the research investigating the dawning of this relation has focused on early word learning and has documented that by roughly their first birthdays, words support the formation of object categories (e.g

The present research examined whether infants acquire general principles or more specific rules when learning about physical events. Experiments 1 and 2 investigated 4.5-month-old infants' ability to judge how much of a tall object should be hidden when lowered behind an occluder versus inside a container. The results indicated that at this age infants are able to reason about height in occlusion but not containment events. Experiment 3 showed that this latter ability does not emerge until about 7.5 months of age. The marked discrepancy in infants' reasoning about height in occlusion and containment events suggests that infants sort events into distinct categories, and acquire separate rules for each category.

Language is a signature of our species and our primary conduit for conveying the contents of our minds. The power of language derives not only from the exquisite detail of the signal itself but also from its intricate link to human cognition. To acquire a language, infants must identify which signals are part of their language and discover how these signals are linked to meaning. At birth, infants prefer listening to vocalizations of human and nonhuman primates; within 3 mo, this initially broad listening preference is tuned specifically to human vocalizations. Moreover, even at this early developmental point, human vocalizations evoke more than listening preferences alone: they engender in infants a heightened focus on the objects in their visual environment and promote the formation of object categories, a fundamental cognitive capacity. Here, we illuminate the developmental origin of this early link between human vocalizations and cognition. We document that this link emerges from a broad biological template that initially encompasses vocalizations of human and nonhuman primates (but not backward speech) and that within 6 mo this link to cognition is tuned specifically to human vocalizations. At 3 and 4 mo, nonhuman primate vocalizations promote object categorization, mirroring precisely the advantages conferred by human vocalizations, but by 6 mo, nonhuman primate vocalizations no longer exert this advantageous effect. This striking developmental shift illuminates a path of specialization that supports infants as they forge the foundational links between human language and the core cognitive processes that will serve as the foundations of meaning.

Because human languages vary in sound and meaning, children must learn which distinctions their language uses. For speech perception, this learning is selective: initially infants are sensitive to most acoustic distinctions used in any language 1-3 , and this sensitivity reflects basic properties of the auditory system rather than mechanisms specific to language 4-7 ; however, infants' sensitivity to non-native sound distinctions declines over the course of the first year 8 . Here we ask whether a similar process governs learning of word meanings. We investigated the sensitivity of 5-month-old infants in an English-speaking environment to a conceptual distinction that is marked in Korean but not English; that is, the distinction between 'tight' and 'loose' fit of one object to another 9,10 . Like adult Korean speakers but unlike adult English speakers, these infants detected this distinction and divided a continuum of motion-into-contact actions into tight-and loose-fit categories. Infants' sensitivity to this distinction is linked to representations of object mechanics 11 that are shared by non-human animals 12-14 . Language learning therefore seems to develop by linking linguistic forms to universal, pre-existing representations of sound and meaning.Our research focuses on the crosscutting conceptual distinctions between actions producing loose-and tight-fitting contact relationships (compare left and right columns in Fig. 1a) and actions producing containment versus support relationships (compare first and second rows in Fig. 1a). As early as Korean and English children begin to talk about such actions, they categorize them differently from one another and similarly to Korean-and English-speaking adults 9,15 . Moreover, English and Korean adults differ in their performance on non-linguistic categorization tasks involving heterogeneous examples of these actions, in accord with the differing semantics of their languages 16,17 , whereas the performance of young children on such tasks has been mixed 9,10,18,19 . These findings suggest that learning the semantics of a natural language influences one's conceptualization of the world 20,21 , but what is the nature of this influence? It is possible that language learning creates new conceptual categories: by hearing the expression 'put on' applied to the actions of placing a book on a table or a ring on a finger, for example, speakers of English may come to perceive similarities among these events 9,21 . Alternatively, sensitivity to conceptual distinctions that are central to the semantics of any human language may emerge before language experience and then be enhanced or diminished by subsequent experience 10 . To investigate these possibilities, we tested the sensitivity of infants living in a monolingual English environment to the conceptual distinction between actions that create tight-and loose-fitting contact relationships, both within and across the English-marked distinction between containment (in) and support (on).Correspondence and requests for ma...

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