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By 24 months, toddlers can process language incrementally using phonology to disambiguate lexical candidates. Adult research shows incremental processing of word meaning; however, this aspect is unclear in research with toddlers. Thus, we investigated the effect of phonological and semantic competition on word recognition in 18- and 24-month-old toddlers. In a preferential-looking task, toddlers looked at semantic-related (taxonomic or thematic) or unrelated pairs of pictures with different or similar phonological onset. The results showed that the 18-month group looked at the target only when the onset of both pictures was different but not when they were similar -regardless of the type of relationship. By contrast, the 24-month group had a similar look pattern as the 18-month group, only in semantically related but not in unrelated pairs. This research suggests that at 24 months of age, toddlers can interpret language incrementally based on phonological and semantic representations.

Bilinguals’ two languages have different degrees of similarity to each other. Words that have common meaning and highly overlapping phonology across languages are known as cognates (e.g. English-Spanish cognate giraffe - jirafa). One method to define language similarity is by counting the number of cognates shared across the two languages, where languages with more cognates are considered more similar. Cognate words have been suggested to be easier to learn than non-cognates, leading more similar languages to be easier to learn overall. This effect of language similarity on vocabulary size has been found in young bilinguals, by using parent-report vocabulary questionnaires with toddlers (Floccia et al., 2018) and receptive vocabulary tasks with school-age children (Blom et al., 2020). Furthermore, this cognate facilitation effect has been found to be stronger in less proficient bilinguals (Bosma, Blom, Hoekstra & Versloot, 2019) and in the less-dominant language (Pérez, Peña & Bedore, 2010). We aim to test these hypotheses in bilingual toddlers using a direct measure of receptive vocabulary, where toddlers respond to a touchscreen task. The task used in this study is an adaptation of a touchscreen task for receptive vocabulary originally tested with monolingual toddlers (Gillen, Siow, Lepadatu, Sucevic, Plunkett & Duta, 2021).

In a paper under revision, we examined the foundations of semantic networks in infancy by uncovering their structural building components. In three experiments, we showed that around 15-months of age, infants begin to construct a semantic network based on associative relationships between words (e.g. bottle/milk). This is followed by the development of a sensitivity to taxonomic links at 18 months, e.g. cat/pig (Delle Luche et al., 2014). These findings highlight the primacy of associative links over taxonomic links in the early lexicon, suggesting that the latter are emergent from experience-based associative relationships. For this registration, we aim to replicate the second experiment with a different set of stimuli, to verify that we can obtain the same result, that is, longer looking times towards lists of pairs of words with an association link (e.g. bird/tree) than for lists of pairs of unrelated words (e.g. cow/ball).

A widely researched question in bilingualism asks whether bilinguals’ vocabulary growth is equal to or lower than that of monolinguals. Some studies have found smaller vocabularies in bilingual toddlers than monolingual toddlers when comparing in one language, but others have found no significant group differences. We compared 12 to 32-month-old bilingual toddlers growing up in the UK with English and one additional language (AL) to age-matched UK English monolinguals. We evaluated both vocabulary size in English and conceptual vocabulary. Bilinguals’ English vocabulary sizes in both comprehension and production were significantly smaller than monolinguals’ after controlling for age and socioeconomic status. This was seen across bilinguals of different levels of language dominance. The bilingual lag in vocabulary size was smaller when calculated using conceptual vocabulary but still significant for both comprehension and production. We discuss the implications for measurements of bilingual toddlers’ vocabulary size.

Selective attention involves attending to task-relevant information and inhibiting task-irrelevant information. While spatial priming is known to efficiently shape selective attention, the nature of language-mediated effects on selective attention is not well-understood, particularly in young toddlers. We com- pare the impact of language-mediated and spatially-mediated attention in an eye-tracking paradigm in which two objects are presented in one of four possible locations and one of the objects is highlighted. The impact of labelling on attention orienting during a prime phase was tested in a subsequent probe phase, where either the identity, location or both were manipulated, and compared to the impact of spatial priming. To elucidate the role of development on these effects, the study was conducted with 18- and 26-month-old toddlers. The results revealed that both language-mediated and spatially-mediated priming lead to attention orienting during the probe phase: at- tended information during the prime phase facilitates attention during the probe phase while ignored features are inhibited. However, in contrast to spatially-mediated attention during the prime phase, language-mediated attention can override these inhibitory effects. The impact of language on overcoming inhibitory effects is particularly noteworthy in the older age group.

Infant vocabulary development is inevitably dependent on the speech they hear in their environment. This paper reports an investigation of the vocabulary statistics that predict a word’s age of acquisition, focusing on frequency and contextual diversity as derived from child-directed speech data along with associative norms generated by adults. Age of acquisition is operationalised using parental-report of infant word knowledge in a British English-speaking population. The work can be considered an extension of Hills, Maouene, Riordan, and Smith (2010) using a fully British English dataset. We found significant effects of both word frequency and word associations on age of acquisition. Interestingly, the strength of these predictors differed between word classes, with frequency being the strongest predictor for nouns and associations the strongest predictor for function words.

We present a neural network model of referent identification in a preferential looking task. The inputs are visual representations of pairs of objects concurrent with unfolding sequences of phonemes identifying the target object. The model is trained to output the semantic representation of the target object and to suppress the semantic representation of the distractor object. Referent identification is achieved in the model based only on bottom-up processing. The training set uses a lexicon of 200 words and their visual and semantic referents, reported by parents as typically known by toddlers. The phonological, visual and semantic representations are derived from real corpora. The model successfully replicates experimental evidence that phonological, perceptual and categorical relationships between target and distractor modulate the temporal pattern of visual attention. In particular, the network captures early effects of phonological similarity, followed by later effects of semantic similarity on referent identification.

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

By about 14 months of age, English infants show sensitivity to mispronunciations of consonants and vowels of familiar and newly learnt words when asked to identify a referent. They are also capable of learning two similar-sounding words. These ?ndings suggest that infants possess phonologically detailed representations of words. However,very little is known about the role that tones play in early lexical representations. Word meaning is also distinguished by tones, which consist primarily of pitch level or contour variations in tonal language, like Chinese. While in English, a typically non-tonal language, pitch change only plays a role in the phrasal level as intonation. This study aims to answer the question: Do 16-month-old Chinese and English infants treat tones as phonological information in their lexical representations? Using the intermodal preferential looking paradigm with the mispronunciation task, study 1 examined whether Chinese infants at 16 months were sensitive to mispronunciations of tones in monosyllabic, familiar words. 15 infants were separated into two groups. For group 1, the familiar words were pronounced correctly in block1, while mispronounced with the falling tone in Mandarin (T4) in block 2. The block order was reversed for the infants in group 2. Using a similar task to study 1, study 2 investigated whether English infants at 16 months were sensitive to tonal change in familiar English words when asked to identify a referent. In contrast with study 1, all the 12 infants received one kind of block order. In block 1, the words were pronounced with T4 as the familiar tone. A falling pitch contour is common in English and quite similar to T4 whereas it is less common to pronounce words with a fall-rise contour in English. Therefore, the dipping tone in Mandarin (T3) was used as the novel tone in block 2 and were considered as tone mispronunciations in study 2. The results of study 1 showed that Chinese infants in group 1 looked longer at a target object when its label was correctly pronounced than when the label was mispronounced, in other words, a mispronunciation effect was found. In group 2, there were no systematic difference in infants' preferences for the target between the pre- and the post-naming phase, neither when the target label was mispronounced or pronounced correctly. The results of study 2 showed that English infants looked longer at a target object when its label was pronounced with T4 than when the label was pronounced with T3. A positive correlation was found between English infants' receptive vocabulary size and their performance in the mispronunciation condition. In conclusion, the results indicate that 1) tones interact with phonological information for both Chinese and English infants at 16 months of age; 2) 16-month-old English infants may be on the way of learning to eliminate the phonological specificity of tone.

We provide evidence that primacy and/or recency effects play a crucial role in infant visual categorization. First, we demonstrate that a connectionist model of infant categorization based number and type of categories formed is modulated by the on a self-organizing map (Gliozzi, Mayor, Hu, & Plunkett, 2009) predicts an increased influence of the first and the last stimuli during familiarization on the category boundaries. We then present data from 10-month-old infants which confirm recency effects. these effects. Future research will allow to discriminate between a primacy or a recency effect.

In a recent article, Bowers (2009) argues that local representations are more consistent with neuro-biological data than distributed representations, as typically generated in Parallel Distributed Processing (PDP) models. We present three reasons why localised neural representations are good candidates for supporting mental representations, as they provide a solution to the trade-off between combinatorial arguments that favour fully-distributed representations and metabolic arguments which favour localist representations.