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Visual world studies show that upon hearing a word in a target-absent visual context containing related and unrelated items, toddlers and adults briefly direct their gaze towards phonologically related items, before shifting towards semantically and visually related ones. We present a neural network model that processes dynamic unfolding phonological representations and maps them to static internal semantic and visual representations. The model, trained on representations derived from real corpora, simulates this early phonological over semantic/visual preference. Our results support the hypothesis that incremental unfolding of a spoken word is in itself sufficient to account for the transient preference for phonological competitors over both unrelated and semantically and visually related ones. Phonological representations mapped dynamically in a bottom-up fashion to semantic-visual representations capture the early phonological preference effects reported in a visual world task. The semantic-visual preference observed later in such a trial does not require top-down feedback from a semantic or visual system.

Category, or property generalization is a central function in the human cognition. It plays a crucial role in a variety of domains, such as learning, everyday reasoning, specialized reasoning, and decision making. Judging the content of a dish as edible, a hormone level as healthy, a building as belonging to the same architectural style as previously seen buildings, are examples of category generalization. In this paper, we propose self-organizing maps as candidates to explain the psychological mechanisms underlying category generalization. Self-organizing maps are psychologically and biologically plausible neural network models that learn after limited exposure to positive category examples, without any need of contrastive information. Just like humans. They reproduce human behavior in category generalization, in particular for what concerns the well-known Numerosity and Variability effects, which are usually explained with Bayesian tools. Where category generalization is concerned, self-organizing maps are good candidates to bridge the gap between the computational level of analysis in Marr's hierarchy (where Bayesian models are situated) and the algorithmic level of aanalysis in Marr's hierarchy (where Bayesian models are situated) and the algorithmic level of analysis in which plausible mechanisms are described., Comment: 24 pages, 3 figures

To what extent do toddlers have shared vocabularies? We examined CDI data collected from 14,607 infants and toddlers in five countries and measured the amount of variability between individual lexicons during development for both comprehension and production. Early lexicons are highly overlapping. However, beyond 100 words, toddlers share more words with other toddlers in comprehension than in production, even when matched for lexicon sizes. This finding points to a structural difference in early comprehension and production: Toddlers are generalists in comprehension but develop a unique, expressive voice. Variability in production decreases after two years of age, suggesting convergence to a common expressive core vocabulary. We discuss potential exogenous and endogenous contributions to the inverted U-shaped development observed in young children's expressive lexical variability.

A longitudinal study, intended to produce a profile of the relationship between cognitive, social, and linguistic development in Danish children, had as subjects a boy and a girl aged 11 and 8 months, who were observed until they reached age 3. Naturalistic language used by the children and their parents, videotaped during regular visits, was analyzed for utterance length and vocabulary and for changes in these factors over time. Significant individual differences could not be explained by simple applications of cognitive theory. Application of a theoretical framework that distinguishes between analytic and holistic processing strategies to explain similarities and differences between the children puts into question the surface validity of some of the objective measures used in language development research. It is suggested that individual differences in development demand a more refined approach than the generalist approaches used in recent years. (MSE)

The primary goal of connectionist research on language acquisition is to identify the nature of the mechanisms that support learning of phonological, semantic, and grammatical processes. A review of literature on language acquisition and connectionism looks at a range of assumptions, general approaches, and their implications. (MSE)

Presents the goals of the Plunkett and Marchman (PM) connectionist model of the acquisition of verb morphology, and responds to related criticisms. Claims that small vocabulary size allows young children to correctly produce both regular and irregular past tense forms, and that non-linearities in vocabulary growth are a contributing factor to the subsequent over-regularizations. (AA)