Comparing apples to manzanas and oranges to naranjas: A new measure of English-Spanish vocabulary for dual language learners.

The valid assessment of vocabulary development in dual-language-learning infants is critical to developmental science. We developed the Dual Language Learners English-Spanish (DLL-ES) Inventories to measure vocabularies of U.S. English-Spanish DLLs. The inventories provide translation equivalents for all Spanish and English items on Communicative Development Inventory (CDI) short forms; extended inventories based on CDI long forms; and Spanish language-variety options. Item-Response Theory analyses applied to Wordbank and Web-CDI data (n = 2603, 12-18 months; n = 6722, 16-36 months; half female; 1% Asian, 3% Black, 2% Hispanic, 30% White, 64% unknown) showed near-perfect associations between DLL-ES and CDI long-form scores. Interviews with 10 Hispanic mothers of 18- to 24-month-olds (2 White, 1 Black, 7 multi-racial; 6 female) provide a proof of concept for the value of the DLL-ES for assessing the vocabularies of DLLs.

Development weaves brains, bodies and environments into cognition.

Understanding how and why human cognition has the properties it does is one of science's fundamental questions. Current thinking in Cognitive Science has delineated two candidate approaches that differ in how they address the question of the relationship between sensory-motor and cognitive processes. In this paper, we add to this discussion by arguing that this question is properly phrased as a developmental question and that ultimately to understand the properties of human cognition we must ask how does human cognition come to have these properties. We conclude that because development weaves brains, bodies and environments into cognition, cognition is inexorably linked to processes of perceiving and acting and inseparable from them.

Ontogenesis of learning and memory: Biopsychosocial and dynamical systems perspectives.

In this article, we review recent empirical and theoretical work on infant memory development, highlighting future directions for the field. We consider the state of the field since Carolyn Rovee-Collier's call for developmental scientists to "shift the focus from what to why," emphasizing the function of infant behavior and the value of integrating fractionized, highly specialized subfields. We discuss functional approaches of early learning and memory, including ecological models of memory development and relevant empirical work in human and non-human organisms. Ontogenetic changes in learning and memory occur in developing biological systems, which are embedded in broader socio-cultural contexts with shifting ecological demands that are in part determined by the infants themselves. We incorporate biopsychosocial and dynamical systems perspectives as we analyze the state of the field's integration of multiple areas of specialization to provide more holistic understanding of the contributing factors and underlying mechanisms of the development of memory.

Non-obvious influences on perception-action abilities.

The sciences of development and learning have been slow to acknowledge that absence of an identifiable experience that relates straightforwardly to a given perception-action ability need not mean that experience per se is irrelevant to the emergence of that ability. A recent study reveals that a difference in diet (plain vs. energy rich) leads to a difference in how rats navigate (use of geometry vs. use of features, respectively). It is a good example of how a seemingly unrelated experience (e.g., what the rats eat) can be a non-obvious yet crucial determiner of perception-action modes. We situate this finding in the broader context of the related conceptions of Schneirla's and Lehrman's Developmental Systems Theory, Gottlieb's Probabilistic Epigenesis, and Bolles's Structure of Learning (see article for references). In doing so we highlight that such phenomena may be the norm, both in development and learning, rather than the exception.

Changing priority maps in 12- to 18-month-olds: an emerging role for object properties.

Everyday action in the world requires the coordination of "where," "when," and "how" with "what." In late infancy, there appear to be changes in how these different streams of information are integrated into the sequential organization of action. An experiment with 12-, 15-, and 18-month-olds was conducted in order to determine the influence of object properties and locations on the sequential selection of targets for reaching. The results reveal a developmental trend from reach decisions' being influenced only by the spatial layout of locations to the overall pattern of reaching's being influenced by the global configuration of object properties to object properties' influencing the sequential decision of what to reach to next. This trend is a new finding regarding the development of goal-directed action in late infancy.

Is cognition enough to explain cognitive development?

Traditional views separate cognitive processes from sensory-motor processes, seeing cognition as amodal, propositional, and compositional, and thus fundamentally different from the processes that underlie perceiving and acting. These were the ideas on which cognitive science was founded 30 years ago. However, advancing discoveries in neuroscience, cognitive neuroscience, and psychology suggests that cognition may be inseparable from processes of perceiving and acting. From this perspective, this study considers the future of cognitive science with respect to the study of cognitive development.

Categorical structure among shared features in networks of early-learned nouns.

The shared features that characterize the noun categories that young children learn first are a formative basis of the human category system. To investigate the potential categorical information contained in the features of early-learned nouns, we examine the graph-theoretic properties of noun-feature networks. The networks are built from the overlap of words normatively acquired by children prior to 2(1/2) years of age and perceptual and conceptual (functional) features acquired from adult feature generation norms. The resulting networks have small-world structure, indicative of a high degree of feature overlap in local clusters. However, perceptual features--due to their abundance and redundancy--generate networks more robust to feature omissions, while conceptual features are more discriminating and, per feature, offer more categorical information than perceptual features. Using a network specific cluster identification algorithm (the clique percolation method) we also show that shared features among these early-learned nouns create higher-order groupings common to adult taxonomic designations. Again, perceptual and conceptual features play distinct roles among different categories, typically with perceptual features being more inclusive and conceptual features being more exclusive of category memberships. The results offer new and testable hypotheses about the role of shared features in human category knowledge.

Longitudinal analysis of early semantic networks: preferential attachment or preferential acquisition?

Analyses of adult semantic networks suggest a learning mechanism involving preferential attachment: A word is more likely to enter the lexicon the more connected the known words to which it is related. We introduce and test two alternative growth principles: preferential acquisition-words enter the lexicon not because they are related to well-connected words, but because they connect well to other words in the learning environment-and the lure of the associates-new words are favored in proportion to their connections with known words. We tested these alternative principles using longitudinal analyses of developing networks of 130 nouns children learn prior to the age of 30 months. We tested both networks with links between words represented by features and networks with links represented by associations. The feature networks did not predict age of acquisition using any growth model. The associative networks grew by preferential acquisition, with the best model incorporating word frequency, number of phonological neighbors, and connectedness of the new word to words in the learning environment, as operationalized by connectedness to words typically acquired by the age of 30 months.