I investigate mechanisms of developmental change and trace the developmental trajectories of higher-level abilities such as language back to their basic-level origins in infancy, in typical and atypical populations.
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Papers by Dean D'Souza
A brief description of three neurodevelopmental disorders
PLOS ONE, 2015
<p>A brief description of three neurodevelopmental disorders.</p
Influencia dinámica entre la interacción padre/madre-hijo y el aprendizaje y el desarrollo cognitivo en el desarrollo típico y atípico
Journal for the Study of Education and Development, Infancia y Aprendizaje, 2016
Attention, eye movement planning and number development in infancy : a cross-syndrome comparison
Numerous studies in animals, adult patients and typically developing infants have suggested that ... more Numerous studies in animals, adult patients and typically developing infants have suggested that there are two kinds of independent cognitive systems for processing numbers: one for computing approximate numerosities and the other for calculating exact number. Studies focussing on adult patients and typically developing infants cannot determine whether the two specialised number systems are prespecified in the infant brain nor map the relationship between these systems in infancy and the outcome over developmental time, as both of the systems are present early in infancy in typical development. However, results from atypical populations, such as Williams syndrome and Down syndrome, will be discussed in order to shed further light upon these questions, arguing that cross-syndrome differences in large number processing in infancy are more predictive of later development of numerical abilities than small number processing. In addition, evidence from cross-syndrome differences in attent...
When modularization fails to occur: A developmental perspective
Cognitive Neuropsychology, 2011
We argue that models of adult cognition defined in terms of independently functioning modules can... more We argue that models of adult cognition defined in terms of independently functioning modules cannot be applied to development, whether typical or atypical. The infant brain starts out highly interconnected, and it is only over developmental time that neural networks become increasingly specialized-that is, relatively modularized. In the case of atypical development, even when behavioural scores fall within the normal range, they are frequently underpinned by different cognitive and neural processes. In other words, in neurodevelopmental disorders the gradual process of relative modularization may fail to occur.
Bilinguals purportedly outperform monolinguals in non-verbal tasks of cognitive control (the ‘bil... more Bilinguals purportedly outperform monolinguals in non-verbal tasks of cognitive control (the ‘bilingual advantage'). The most common explanation is that managing two languages during language production constantly draws upon, and thus strengthens, domain-general inhibitory mechanisms (Green 1998 Biling. Lang. Cogn. 1 , 67–81. ( doi:10.1017/S1366728998000133 )). However, this theory cannot explain why a bilingual advantage has been found in preverbal infants (Kovacs & Mehler 2009 Proc. Natl Acad. Sci. USA 106 , 6556–6560. ( doi:10.1073/pnas.0811323106 )). An alternative explanation is needed. We propose that exposure to more varied, less predictable (language) environments drive infants to sample more by placing less weight on consolidating familiar information in order to orient sooner to (and explore) new stimuli. To confirm the bilingual advantage in infants and test our proposal, we administered four gaze-contingent eye-tracking tasks to seven- to nine-month-old infants who w...
Emerging evidence suggests that early bilingual experience constrains the development of attentio... more Emerging evidence suggests that early bilingual experience constrains the development of attentional processes in infants, and that some of these early bilingual adaptations could last into adulthood. However, it is not known whether the early adaptations in the attentional domain alter more general cognitive abilities. If they do, then we would expect that bilingual adults who learned their second language early in life would score more highly across cognitive tasks than bilingual adults who learned their second language later in life. To test this hypothesis, 170 adult participants were administered a well-established (non-verbal) measure of fluid intelligence: Raven’s Advanced Progressive Matrices (RAPM). Fluid intelligence (the ability to solve novel reasoning problems, independent of acquired knowledge) is highly correlated with numerous cognitive abilities across development. Performance on the RAPM was greater in bilinguals than monolinguals, and greater in ‘early bilinguals’...
Infants raised in bilingual homes redirect attention faster than infants raised in monolingual ho... more Infants raised in bilingual homes redirect attention faster than infants raised in monolingual homes. How can mere exposure to a bilingual environment affect an infant's cognitive development? The more complex language environment may drive infants to explore (gather more information from) their visual environment to facilitate learning.
Proceedings of the National Academy of Sciences, 2012
One might expect that children with varying genetic mutations or children raised in low socioecon... more One might expect that children with varying genetic mutations or children raised in low socioeconomic status environments would display different deficits. Although this expectation may hold for phenotypic outcomes in older children and adults, cross-syndrome comparisons in infancy reveal many common neural and sociocognitive deficits. The challenge is to track dynamic trajectories over developmental time rather than focus on end states like in adult neuropsychological studies. We contrast the developmental and adult approaches with examples from the cognitive and social domains, and we conclude that static models of adult brain lesions cannot be used to account for the dynamics of change in genetic and environmentally induced disorders in children.
To adapt to their more varied and unpredictable (language) environments, infants from bilingual h... more To adapt to their more varied and unpredictable (language) environments, infants from bilingual homes may gather more information (sample more of their environment) by shifting their visual attention more frequently. However, it is not known whether this early adaptation is age-specific or lasts into adulthood. If the latter, we would expect to observe it in adults who acquired their second language early, not late, in life. Here we show that early bilingual adults are faster at disengaging attention to shift attention, and at noticing changes between visual stimuli, than late bilingual adults. In one experiment, participants were presented with the same two visual stimuli; one changed (almost imperceptibly), the other remained the same. Initially, participants looked at both stimuli equally; eventually, they fixated more on the changing stimulus. This shift in looking occurred in the early but not late bilinguals. It suggests that cognitive processes adapt to early bilingual experi...
The Significance of Cognitive Neuroscience: Findings, Applications, and Challenges
ABSTRACT Each edition of this classic reference has proved to be a benchmark in the developing fi... more ABSTRACT Each edition of this classic reference has proved to be a benchmark in the developing field of cognitive neuroscience. The fifth edition of The Cognitive Neurosciences continues to chart new directions in the study of the biological underpinnings of complex cognitio -- the relationship between the structural and physiological mechanisms of the nervous system and the psychological reality of the mind. It offers entirely new material, reflecting recent advances in the field. Many of the developments in cognitive neuroscience have been shaped by the introduction of novel tools and methodologies, and a new section is devoted to methods that promise to guide the field into the future -- from sophisticated models of causality in brain function to the application of network theory to massive data sets. Another new section treats neuroscience and society, considering some of the moral and political quandaries posed by current neuroscientific methods. Other sections describe, among other things, new research that draws on developmental imaging to study the changing structure and function of the brain over the lifespan; progress in establishing increasingly precise models of memory; research that confirms the study of emotion and social cognition as a core area in cognitive neuroscience; and new findings that cast doubt on the so-called neural correlates of consciousness.
Aims and objectives: In this commentary article we consider the benefits of adopting a neuroconst... more Aims and objectives: In this commentary article we consider the benefits of adopting a neuroconstructivist approach in the study of bilingualism in order to promote empirical and theoretical progress on the fiercely debated issue of whether bilingualism confers genuine cognitive advantages. Significance/implications: Although there is a general consensus that exposure to multilingual environments does not impair cognitive development, there are still doubts on the possible beneficial advantages of bilingualism. Critics argue that the evidence for this advantage might have been confounded by unsound or questionable methodological practices. Some investigators have abandoned research in this area, indicating either that there is no bilingual advantage or that it is impossible to capture and therefore rule out alternative explanations for group differences. Rather than dismissing this important theme in the literature, we advocate a more systematic approach in which the effects of mult...
The ability to acquire language is a critical part of human development. Yet there is no consensu... more The ability to acquire language is a critical part of human development. Yet there is no consensus on how the skill emerges in early development. Does it constitute an innately-specified, language-processing module or is it acquired progressively? One of Annette Karmiloff-Smith’s (1938–2016) key contributions to developmental science addresses this very question. Karmiloff-Smith persistently maintained that the process of development itself constitutes a crucial factor in phenotypic outcomes. She proposed that cognitive modules gradually emerge through a developmental process – ‘progressive modularization’. This concept helped to advance the field beyond the stale nature–nurture controversy. It enabled language researchers to develop more nuanced transactional frameworks that take seriously the integration of genes and environment. In homage to Karmiloff-Smith, the current article describes the importance of her work to the field of developmental psychology and language research. It...
Smith, Annette (2016) Parent-child interaction as a dynamic contributor to learning and cognitive... more Smith, Annette (2016) Parent-child interaction as a dynamic contributor to learning and cognitive development in typical and atypical development / Influencia dinámica entre la interacción padre/madre-hijo y el aprendizaje y el desarrollo cognitivo en el desarrollo típico y atípico. Infancia y Aprendizaje 39 (4), pp. 694-726.
Attentional abilities constrain language development: A cross‐syndrome infant/toddler study
Developmental Science
Typically developing (TD) infants adapt to the social world in part by shifting the focus of thei... more Typically developing (TD) infants adapt to the social world in part by shifting the focus of their processing resources to the relevant aspects of a visual scene. Any impairment in visual orienting may therefore constrain learning and development in domains such as language. However, although something is known about visual orienting in infants at risk of autism, very little is known about it in infants/toddlers with other neurodevelopmental disorders. This is partly because previous studies focused on older children and rarely compared the children to both chronological- and mental-age matched TD controls. Yet, if visual orienting is important for learning and development, then it is imperative to investigate it early in development and ascertain whether it relates to higher-level cognitive functions such as language. We used eye tracking technology to directly compare visual orienting in infants/toddlers with one of three neurodevelopmental disorders-Down syndrome (DS), fragile X syndrome (FXS), and Williams syndrome (WS)-matched on chronological- or mental-age to TD controls (~15 months). We also measured language ability using the Mullen Scales of Early Learning. We found that the ability to disengage attention from a visual stimulus in order to shift it to another visual stimulus is related to language ability in infants/toddlers irrespective of group affiliation. We also found that, contrary to the literature, infants and toddlers with DS (but not WS) are slow at disengaging attention. Our data suggest that orienting attention constrains language development and is impaired in DS.
Sleep is atypical across neurodevelopmental disorders in infants and toddlers: A cross-syndrome study
Research in Developmental Disabilities
Emergent and constrained: Understanding brain and cognitive development
The Journal of neuroscience : the official journal of the Society for Neuroscience, Jan 18, 2016
Editor's Note: These short, critical reviews of recent papers in the Journal, written exclusively... more Editor's Note: These short, critical reviews of recent papers in the Journal, written exclusively by graduate students or postdoctoral fellows, are intended to summarize the important findings of the paper and provide additional insight and commentary. For more information on the format and purpose of the Journal Club, please see http://www.jneurosci.org/misc/ifa_features.shtml.
In order to understand how language abilities emerge in typically and atypically developing infan... more In order to understand how language abilities emerge in typically and atypically developing infants and toddlers, it is important to embrace complexity in development. In this paper, we describe evidence that early language development is an experience-dependent process, shaped by diverse, interconnected, interdependent developmental mechanisms, processes, and abilities (e.g. statistical learning, sampling, functional specialization, visual attention, social interaction, motor ability). We also present evidence from our studies on neurodevelopmental disorders (e.g. Down syndrome, fragile X syndrome, Williams syndrome) that variations in these factors significantly contribute to language delay. Finally, we discuss how embracing complexity, which involves integrating data from different domains and levels of description across developmental time, may lead to a better understanding of language development and, critically, lead to more effective interventions for cases when language dev...
Face processing is a crucial socio-cognitive ability. Is it acquired progressively or does it con... more Face processing is a crucial socio-cognitive ability. Is it acquired progressively or does it constitute an innately-specified, face-processing module? The latter would be supported if some individuals with seriously impaired intelligence nonetheless showed intact faceprocessing abilities. Some theorists claim that Williams syndrome (WS) provides such evidence since, despite IQs in the 50s, adolescents/adults with WS score in the normal range on standardized face-processing tests. Others argue that atypical neural and cognitive processes underlie WS face-processing proficiencies. But what about infants with WS? Do they start with typical face-processing abilities, with atypicality developing later, or are atypicalities already evident in infancy? We used an infant familiarization/novelty design and compared infants with WS to typically developing controls as well as to a group of infants with Down syndrome matched on both mental and chronological age. Participants were familiarized with a schematic face, after which they saw a novel face in which either the features (eye shape) were changed or just the configuration of the original features. Configural changes were processed successfully by controls, but not by infants with WS who were only sensitive to featural changes and who showed syndrome-specific profiles different from infants with the other neurodevelopmental disorder. Our findings indicate that theorists can no longer use the case of WS to support claims that evolution has endowed the human brain with an independent face-processing module.
Identifying genotype/phenotype relations in human social cognition has been enhanced by the study... more Identifying genotype/phenotype relations in human social cognition has been enhanced by the study of Williams syndrome (WS). Indeed, individuals with WS present with a particularly strong social drive, and researchers have sought to link deleted genes in the WS critical region (WSCR) of chromosome 7q11.23 to this unusual social profile. In this paper, we provide details of two case studies of children with partial genetic deletions in the WSCR: an 11-year-old female with a deletion of 24 of the 28 WS genes, and a 14-year-old male who presents with the opposite profile, i.e., the deletion of only four genes at the telomeric end of the WSCR. We tested these two children on a large battery of standardized and experimental social perception and social cognition tasks -both implicit and explicit -as well as standardized social questionnaires and general psychometric measures. Our findings reveal a partial WS socio-cognitive profile in the female, contrasted with a more autistic-like profile in the male. We discuss the implications of these findings for genotype/phenotype relations, as well as the advantages and limitations of animal models and of case study approaches.
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Papers by Dean D'Souza