Experience-dependent brain development as a key to understanding the language system

An influential view of the nature of the language system is that of an evolved biological system in which a set of rules is combined with a lexicon that contains the words of the language together with a representation of their context. Alternative views, usually based on connectionist modeling, attempt to explain the structure of language on the basis of complex associative processes. Here I put forward a third view that stresses experience-dependent structural development of the brain circuits supporting language as a core principle of the organization of the language system. On this view, embodied in a recent neuroconstructivist neural network of past tense development and processing, initial domain-general predispositions enable the development of functionally specialized brain structures through interactions between experience-dependent brain development and statistical learning in a structured environment. Together, these processes shape a biological adult language system that appears to separate into distinct mechanism for processing rules and exceptions, whereas in reality those subsystems co-develop and interact closely. This view puts experience-dependent brain development in response to a specific language environment at the heart of understanding not only language development but adult language processing as well

A learned label modulates object representations in 10-month-old infants

Despite substantial evidence for a bidirectional relationship between language and representation, the roots of this relationship in infancy are not known. The current study explores the possibility that labels may affect object representations at the earliest stages of language acquisition. We asked parents to play with their 10-month-old infants with two novel toys for three minutes, every day for a week, teaching infants a novel word for one toy but not the other. After a week infants participated in a familiarization task in which they saw each object for 8 trials in silence, followed by a test trial consisting of both objects accompanied by the trained word. Infants exhibited a faster decline in looking times to the previously unlabeled object. These data speak to the current debate over the status of labels in human cognition, supporting accounts in which labels are an integral part of representation

Implicit vs. explicit learning in German noun plurals

Over the past few decades there has been a lot of debate about language learning and the opinion about the status of mental rule during the process of language learning is still divided between different researches. The present study examines learning morphology of German noun plurals based on rules, examples or on both, rules and examples. The results across these three experimental conditions suggest that the morphological patterns are learned more easily in the form of rules and thus, seem to be more easily captured by dual-route (which suggest that rules and exceptions are processed by two qualitatively different mechanisms) than single route theories (which suggest a singe mechanism for processing both rules and exceptions). However, a closer examination of error patterns across the five rules (-e, -n, -er, Ø, -s) revealed results confronting dual-route theories and suggest the existence of two rulemechanisms (-n and -s) rather than one for learning regular inflection in German plural nouns. Moreover, the second rule (with plural ending -n) was the easiest one to be learned, although it is the fifth rule (with plural ending -s) which is considered as a default rule in German

Pupillometry in infancy research

The human pupil is a small opening in each eye that dilates in response not only to changes in luminance but also to novel events. This makes changes in pupil diameter an attractive measure in studies on infants’ and young children’s physical and social cognition. However, designing and interpreting pupillometry studies for developmental populations comes with its own caveats. Here we give an overview of how psychologically induced changes in pupil diameter have been investigated and interpreted in developmental studies. We highlight the methodological challenges when designing experiments for infants and young children and provide several suggestions to address common problems. The fact that pupillometry provides a sensitive measure of the time course of responses to novelty extends the scope of possibilities for researchers studying infant cognition and development

A neurocomputational model of the effect of learned labels on infants’ object representations

The effect of labels on nonlinguistic representations is the focusof substantial debate in the developmental literature. A recentempirical study (Twomey & Westermann, 2016) suggested thatlabels are incorporated into object representations, such thatinfants respond differently to objects for which they know alabel relative to unlabeled objects. However, these empiricaldata cannot differentiate between two recent theories ofintegrated label-object representations, one of which assumeslabels are features of object representations, and one whichassumes labels are represented separately, but become closelyassociated with learning. We address this issue using aneurocomputational (auto-encoder) model to instantiate boththeoretical approaches. Simulation data support an account inwhich labels are features of objects, with the samerepresentational status as the objects’ visual and hapticcharacteristics

Constructivist neural network models of cognitive development

In this thesis I investigate the modelling of cognitive development with constructivist neural networks. I argue that the constructivist nature of development, that is, the building of a cognitive system through active interactions with its environment, is an essential property of human development and should be considered in models of cognitive development. I evaluate this claim on the basis of evidence from cortical development, cognitive development, and learning theory. In an empirical evaluation of this claim, I then present a constructivist neural network model of the acquisition of the English past tense and of impaired inflectional processing in German agrammatic aphasics. The model displays a realistic course of acquisition, closely modelling the U-shaped learning curve and more detailed effects such as frequency and family effects. Further, the model develops double dissociations between regular and irregular verbs. I argue that the ability of the model to account for the hu..

Investigating the association between children’s screen media exposure and vocabulary size in the UK

Children are growing up in a digital age with increasing exposure to television and touchscreen devices. We tested whether exposure to screen media is associated with children’s early language development. One hundred and thirty-one highly educated caregivers of UK children aged 6–36 months completed a media exposure questionnaire and vocabulary measure. 99% of children were read to daily, 82% watched television, and 49% used mobile touchscreen devices daily. Regression analyses revealed that time spent reading positively predicted vocabulary comprehension and production scores at 6–18 months, but time spent engaging with television or mobile touchscreen devices was not associated with vocabulary scores. Critically, correlations revealed that time spent reading or engaging with other non-screen activities was not offset by time spent engaging with television or mobile touchscreen devices. Thus, there was no evidence to suggest that screen media exposure adversely influenced vocabulary size in our sample of highly educated families with moderate media use

Predictive processing and developmental language disorder

Purpose: Research in the cognitive and neural sciences has situated predictive processing – the anticipation of upcoming percepts – as a dominant function of the brain. The purpose of this article is to argue that prediction should feature more prominently in explanatory accounts of sentence processing and comprehension deficits in developmental language disorder (DLD). Method: We evaluate behavioural and neurophysiological data relevant to the theme of prediction in early typical and atypical language acquisition and processing. Results: Poor syntactic awareness – attributable in part to an underlying statistical learning deficit – is likely to impede syntax-based predictive processing in children with DLD, conferring deficits in spoken sentence comprehension. Furthermore, there may be a feedback cycle in which poor syntactic awareness impedes children’s ability to anticipate upcoming percepts, and this in turn makes children unable to improve their syntactic awareness on the basis of prediction error signals. Conclusion: This article offers a re-focusing of theory on sentence processing and comprehension deficits in DLD, from a difficulty in processing and integrating perceived syntactic features, to a difficulty in anticipating what is coming next

Verb Inflections in German Child Language: A Connectionist Account

The emerging function of verb inflections in German lenguage acquisition is modeled with a connectionist network. A network that is initially presented only with a semantic representation of sentences uses the inflectional verb ending -t to mark those sentences that are low in transitivity, whereas all other verb endings occur randomly. This behavior matches an early stage in German language acquisition where verb endings encode a similar semantic rather than a grammatical function. When information about the siuface structure of the sentence is added to the input data, the network learns to use the correct verb inflections in a process very similar to children's learning. This second phase is facilitated by the semeintic phase, suggesting that there is no shift from semantic to grammatical encoding, but rather an extension of the initial semantic encoding to include grammatical information. This can be seen as evidence for the strong version of the functionalist hypothesis of language acquisition

Evaluating the replicability and specificity of evidence for natural pedagogy theory

Do infants understand that they are being communicated to? This thesis first outlines issues facing the field of infancy research that affect confidence in the literature on this (and any) topic to date. Following this, an introductory chapter evaluates evidence for the three core claims of Natural Pedagogy (NP), and the compatibility of this evidence with alternative theories. This is followed by three experimental chapters. In Study 1, we attempted two replications of the study with the highest theoretical value for NP (Yoon et al., 2008). This study has high stakes theoretically, as it is the only study providing evidence for the most specific claim of NP that is difficult to explain by low-level mechanisms. Therefore, a replication of this result that included a reduction of possible confounds and a more sophisticated measure of attention throughout the task was of great theoretical value. In this study, we were unable to replicate the original findings. In Study 2 we went beyond the evidence for the claims made in the outline of NP, and instead generated a new, specific prediction that we believe NP would make. This is important, as theories are only useful if they can make clear, testable predictions. In this study, we pitted pedagogically demonstrated actions and simple actions against each other and evaluated infants’ transmission of these actions to someone else. We found no evidence for NP, finding evidence for preferential transmission of simple actions instead. In Study 3 we went beyond NP, and tested a clear prediction stemming from an alternative low-level theory for how infants develop gaze-following ability. We found evidence that infants learn to gaze-follow through reinforcement. Overall, this thesis contributes to the vast literature on infants as recipients of communication, as well as highlighting methods for conducting open and reproducible infancy research