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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.

Recent work has investigated the origin of infant colour categories, showing pre-linguistic infants categorise colour even in the absence of colour words. These infant categories are similar but not identical to adult categories, giving rise to an important question about how infant colour perception changes with the learning of colour words. Here we present two novel paradigms in which 12- and 19-month-old participants learning English as their first language were assessed on their perception of colour, while data on their colour word comprehension were also collected. Results indicate that participants' perception of colours close to the colour category boundaries dramatically change after colour word learning. The results highlight the shift made from infant colour categories to adult-like linguistically mediated colour categories that accompanies colour word learning.

We present a neural network model of referent identification in a visual world task. Inputs are visual representations of item pairs unfolding with sequences of phonemes identifying the target item. The model is trained to output the semantic representation of the target and to suppress the distractor. The training set uses a 200-word lexicon typically known by toddlers. The phonological, visual, and semantic representations are derived from real corpora. Successful performance requires correct association between labels and visual and semantic representations, as well as correct location identification. The model reproduces experimental evidence that phonological, perceptual, and categorical relationships modulate item preferences. The model provides an account of how language can drive visual attention in the inter-modal preferential looking task.

Durante os últimos 15 anos, redes neuroniais ou técnicas de modelagem conexionista tem sido usada para ajudar-nos a compreender como os indivíduos adquirem, mantem e, em alguns casos, perdem funções mentais. Este artigo oferece uma breve introdução aos princípios subjacentes à operação de redes neuroniais conexicionistas e oferece algumas sugestões de por que elas tem provocado tanta controvérsia dentro do campo das ciências cognitivas. Algumas aplicações da modelagem conexionista, enfocando o domínio da leitura em voz alta, são usadas para ilustrar os princípios conexionistas em ação. O artigo termina com algumas breves sugestões de rumos para o futuro

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.

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.

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.

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 phonolog-ically related items, before shifting towards semantically andvisually related ones. We present a neural network model thatprocesses dynamic unfolding phonological representations andmaps them to static internal semantic and visual representa-tions. The model, trained on representations derived from realcorpora, simulates this early phonological over semantic/visualpreference. Our results support the hypothesis that incremen-tal unfolding of a spoken word is in itself sufficient to ac-count for the transient preference for phonological competi-tors over both unrelated and semantically and visually relatedones. Phonological representations mapped dynamically in abottom-up fashion to semantic-visual representations capturethe early phonological preference effects reported in a visualworld task. The semantic-visual preference observed later insuch a trial does not require top-down feedback from a seman-tic or visual system.

Recent years have seen a rise in the popularity of eye-tracking methods to evaluate infant and toddler interpretation of visual stimuli. The application of these methods makes it increasingly important to understand the development of infant sensitivity to the perceptual properties implicated in such methods. In light of recent studies that demonstrate the use of pseudoisochromatic plates in testing infants for color vision, we investigated the perceptual contouring abilities required to pass a color-vision test of this type. A total of 115 (51 female) 16- and 19-month-old U.K.-based participants from the Oxfordshire region participated in this study. The evidence collected in this study indicated their ability to systematically fixate a contoured target, but the speed at which they did so was much slower in the younger age group. These findings suggest that the perceptual contouring abilities implicated in this study are still under development in the second year of life, and as such, the results suggest a lower age limit for color-vision tests displayed in this format.

When and how do infants learn color words? It is generally supposed that color words are learned late and with a great deal of difficulty. By examining infant language surveys in British English and 11 other languages, this study shows that color word learning occurs earlier than has been previously suggested and that the order of acquisition of color words is similar in related languages. This study also demonstrates that frequency and syllabic complexity can be used to predict variability in infant color word learning across languages. In light of recent evidence indicating that color categories have universal biological foundations, these findings suggest that infants' experience and linguistic exposure drive their shift to culturally and linguistically mediated adult-like understandings of color words.

Colour word learning has traditionally been viewed as a diffi-cult task. Previous accounts have focussed on infants’ ability toshow an adult-like understanding of colour terms. Here we ex-amine whether infants understand colour terms at a basic level,using two different methods: first, evidence from parental re-ports that British infants can comprehend colour terms early,second from experimental data using eye-tracking. These find-ing show that colour word learning is a process that beginsmuch earlier than previously thought, and develops slowly asinfants learn where the boundaries of each term are located.Due to their abstract properties, colour words present a uniqueopportunity to assess category learning in infants, as well asthe mechanisms that control word learning in general.

During the first year of life, infants develop a remarkable ability togroup objects based on their similarities and differences. Thisability of category formation represents one of the mainmechanisms underlying the organisation of the semantic system.Early categories are formed spontaneously, in a non-supervisedfashion and this type of category acquisition remains present evenwhen more sophisticated forms of supervised category learningemerge. Even though there are various models of categorisationmechanisms across the lifespan, there is a gap in the researchinvestigating implicit categorisation at different stages of cognitivedevelopment. Therefore, the aim of the current study was tocompare processes of spontaneous concept formation in infantsand adults using an experimental paradigm based on noveltypreference. We discovered that both infants and adults showevidence of category learning (Experiment 1), though withdifferent amount of training being needed to achieve the task.Adults successfully categorised objects already after a single blockof training. Infants reached a level comparable to that of adultsafter twice the amount of training. As these tasks inevitably posedifferent cognitive and sensory demands to the two groups, inExperiments 2 and 3 we explored how varying parameters of thelearning context affect dynamics of category formation.Decreasing memory demands of the task resulted in anacceleration of infants’ category formation (Experiment 2),whereas posing memory load in an implicit category learning taskdecelerated adults’ dynamics of category formation (Experiment3).

Visual closure is the ability to complete a picture from partial information. In children it is a requisite in manyskills such as fluent reading, and is also used in many tests of colour vision. Here we present a test of visual closure in infantsacross two age groups, 1;4 and 1;7, both to test their abilities in visual closure, but also as a prototype for a colour vision testfor younger infants. The results of the study show evidence of development in visual closure abilities across those two ages,suggesting that visual closure is a perceptual ability that continues to develop in the second year of life. The results of this studyare discussed in terms of perceptual development in infants and toddlers, and have consequences for both medical and scientificunderstanding of visual closure in children.

An ongoing debate concerns whether spoken word recognition happens in an incremental or continuous manner(Marslen-Wilson & Zwitserlood, 1989; McClelland & Elman, 1986). In the current study, participants (31 adults and 49 infantsaged 24-30months) were presented with four images while they heard a sentence like “Look at the cat”. Among the imageswas one object that rhymed with the spoken word, one object that shared its onset and two phonologically unrelated objects.Growth curve analysis of eye-tracking data revealed that adults preferentially fixated onset competitors over unrelated objectssoon after word onset but did not preferentially fixate rhyme competitors. Fixations of the onset competitors were modulatedby the degree to which the onsets of the three remaining competitors were phonologically similar to the spoken word. Infantsshowed no preference for either type of phonologically related competitor. The absence of a rhyme effect contradicts continuoustheories of spoken word recognition.

Previous research has highlighted the difficulty that infants have in learning to use color words. Even after acquiring the words themselves, infants are reported to use them incorrectly, or overextend their usage. We tested 146 infants from 5 different age groups on their knowledge of 6 basic color words, "red", "green", "yellow", "blue", "black", and "white", using an intermodal preferential looking task. The results showed that infants show reliable comprehension of color words as early as 19 months of age. No order of acquisition effects were observed. In addition, infants' behavior in the task was facilitated by the provision of redundant noun information, "Look at the red car," and even general referential noun phrases, "Look at the red one," with greater looking to the target than when the color label was not presented in adjective position, "Look, red." The findings indicate that color words may be learned with greater ease than previously thought, verifying recent parental reports showing similar findings. The findings also suggest that 19 month olds have already developed an expectation that color labels should occur in adjectival position.

A broad range of studies demonstrate that sleep has a facilitating role in memory consolidation (see Rasch & Born, 2013). Whether sleep-dependent memory consolidation is also apparent in infants in their first few months of life has not been investigated. We demonstrate that 3-month-old infants only remember a cartoon face approximately 1.5-2 hours after its first presentation when a period of sleep followed learning. Furthermore, habituation time, that is, the time to become bored with a stimulus shown repetitively, correlated negatively with the density of infant sleep spindles, implying that processing speed is linked to specific electroencephalographic components of sleep. Our findings show that without a short period of sleep infants have problems remembering a newly seen face, that sleep enhances memory consolidation from a very early age, highlighting the importance of napping in infancy, and that infant sleep spindles may be associated with some aspects of cognitive ability.

Recent studies with infants and adults demonstrate a facilitative role of labels in object categorization. A common interpretation is that labels highlight commonalities between objects. However, direct evidence for such a mechanism is lacking. Using a novel object category with spatially separate features that are either of low or high variability across the stimulus set, we tracked 12-month-olds' attention to object features during learning and at test. Learning occurred in both conditions, but what was learned depended on whether or not labels were heard. A detailed analysis of eye movements revealed that infants in the two conditions employed different object processing strategies. In the silent condition, looking patterns were governed exclusively by the variability of object parts. In the label condition, infants' categorization performance was linked to their relative attention to commonalities. Moreover, the commonality focus persisted after learning even in the absence of labels. These findings constitute the first experimental evidence that labels induce a persistent focus on commonalities.

Background: The facilitating role of sleep for language learning is well-attested in adults and to a lesser extent in infants and toddlers. However, the longitudinal relationship between sleep patterns and early vocabulary development is not well understood. Methods: This study investigates how measures of sleep are related to the development of vocabulary size in infants and toddlers. Day and night-time sleeping patterns of infants and toddlers were compared with their concurrent and subsequent vocabulary development. Sleep assessments were conducted using a sleep diary specifically designed to facilitate accurate parental report. Sleep measures were used as predictors in a multilevel growth curve analysis of vocabulary development. Results: The number of daytime naps was positively associated with both predicted expressive (p = 0.062) and receptive vocabulary growth (p = 0.006), whereas the length of night-time sleep was negatively associated with rate of predicted expressive vocabulary growth (p = 0.045). Sleep efficiency was also positively associated with both predicted receptive (p = 0.001) and expressive vocabulary growth (p = 0.068). Conclusions: These results point to a longitudinal relationship between sleep and language development, with a particular emphasis on the importance of napping at this age.