Developmental Science

Speech consists of regularities at different timescales. Already during infancy, neural electrophysiological activity aligns to these rhythms. The degree to which infants exhibit neural tracking of speech can be linked to their language development. In this study, we examined how the neural tracking of sung speech develops across age, from infancy to early childhood, and across different frequency bands (i.e., at the stress, syllabic, and phonemic rates), and whether neural tracking at each frequency and age predicts childrens language outcomes. We included 2565 children of the longitudinal YOUth cohort. Children listened to Dutch sung nursery rhymes while EEG was recorded at three measurement waves. After preprocessing the data, we included 955 children at 5 months, 1048 children at 10 months, and 795 children at 2-4 years. The final sample consisted of 750 children who also completed a receptive vocabulary test at 2-4 years. Children from 5 months onwards showed significant neural tracking of stressed syllables, syllables, and phonemes, measured with speech-brain coherence (SBC). Unexpectedly, there were no developmental changes in SBC across different frequency bands from infancy to early childhood. As expected, children with larger receptive vocabularies showed increased SBC in the stressed syllable rate. These findings suggest that stronger tracking of stressed syllables is related to individual differences in language ability.

Acquiring reading proficiency, unlike spoken language, requires the brain to engage several specialized neural systems to map visual symbols (letters) to their corresponding phonological sounds (audiovisual integration), laying the foundation for fluent reading. This study investigates the neural and behavioral trajectory of developing audiovisual (AV) integration during the first year of learning to read. Thirty-two healthy Hebrew-speaking first-grade children were assessed at 3 time points across the school year: beginning, middle, and end of first grade. Participants underwent behavioral testing and brain fMRI scans while performing a block-design fMRI task involving AV matching or non-matching letters and sounds. Together with improvement in behavioral test scores related to general abilities, working memory, cognitive flexibility, and phonemic abilities, a Drift Diffusion Modeling (DDM) analysis of the accuracy and reaction time across sessions suggested faster and more efficient responses as the year progressed. fMRI results showed a significant increase in activation, from the beginning to the end of the first grade, in the left superior temporal gyrus (STG), frontal cortices and parietotemporal cortices, with a shift towards left-lateralization in the fusiform gyrus at the end of the year. These findings point towards the second half of the first grade as the time window for neural specialization and lateralization to phonological and orthographic information. A significant positive correlation between the fusiform gyrus activation and naming objects and colors scores across all sessions links this neural specialization to cognitive flexibility behavioral skills. Key pointsO_LISignificant increase, predominantly between the middle and end of the first grade, in activation in fusiform, left superior temporal, frontal, and parietotemporal cortices across the first grade. C_LIO_LISignificant left lateralization in the fusiform gyrus at the end of first grade. C_LIO_LIPositive correlation between naming skills and a bilateral fusiform gyrus activation throughout the first grade. C_LI

In children, the ability to listen to relevant auditory information and suppress distracting information is a foundational skill for learning and educational achievement. Distractibility is supported by multiple cognitive components (voluntary attention orienting, sustained attention, distraction, phasic arousal, as well as impulsivity and motor control) that may mature at different ages. Here we used the Competitive Attention Test (CAT) to measure these components in 71 4- and 5-year-old children. The goal of this study was to characterize the changes in efficiency of attention during the preschool period, and to explore differences in distractibility in preschool children that could be related to the socioeconomic status (SES) background of the childs family. We found that sustained attention improves from age 4 to 5, while voluntary attention orienting is still immature during the preschool period. In addition, independent of age, task-irrelevant sounds induced distraction, phasic arousal, and impulsivity. Children from lower SES backgrounds showed reduced sustained attention abilities and increased impulsivity. However, 3-year-old children and a minority of 4- and 5-year-olds did not manage to perform the task according to the instructions; the CAT thus seems suitable to assess distractibility only in preschoolers with sufficiently developed sustained attention skills to efficiently complete the task. Taken together, the present findings suggest that distractibility is still developing during the preschool period and is likely to vary depending on the SES background of a childs family.

Platos Republic, Einsteins Theory of relativity, Vilvadis Four Seasons are all remarkable examples of humans unique ability to create and manipulate complex abstract structures, whether in language, mathematics or music. Yet the mechanisms by which children develop such abstract thinking, and the role of education and structured experiences such as musical practice in shaping these abilities remain unclear. To explore these questions, we conducted cross-sectional behavioral experiments with 566 children aged 4 to 8, spanning four educational grades, half of whom participated in a violin training program since the age of four. Two experiments examined how children encode, process and compress auditory sequences and visual patterns, while a third examined their sensitivity to geometric regularities. Our results reveal the emergence of symbolic reasoning as early as the start of formal schooling, yet with deeper abstraction as a function of grade. By first grade, children encoded complex auditory sequences within a Language of Thought (LoT) similar to adults. Additionally, when confronted with quadrilaterals, children showed increasing sensitivity to geometric regularities, suggesting a developmental transition from perceptual to symbolic reasoning. However, we did not observe significant impact of musical practice on abstraction abilities across any of the domains tested. We discuss whether and how the impact of education and extracurricular activities such as music could be enhanced.

Neural oscillations synchronize to the rhythmic structure of speech, a process known as cortical tracking that is thought to support speech perception and language acquisition. Individual differences in cortical tracking during infancy predict later language outcomes, yet little is known about whether this neural mechanism can be shaped by recent auditory experience early in development. Here, we tested whether brief exposure to structured musical rhythms modulates cortical tracking of speech in Spanish-Basque bilingual infants at 6 and 10 months of age. Infants listened to speech preceded by either temporally regular musical sequences that mirrored the rhythmic structure of the speech signal or rhythmically irregular musical sequences. Cortical tracking was measured using electroencephalography and quantified as speech-brain coherence in the delta and theta frequency bands. Regular musical sequences enhanced subsequent cortical tracking of speech, but the effects varied across age, language, and frequency band. In Spanish, rhythmic priming enhanced delta-band tracking at 10 months of age, whereas in Basque it enhanced theta-band tracking at both 6 and 10 months. These language-specific effects suggest that rhythmic priming interacts with the temporal properties of individual languages and infants' developing linguistic experience. Together, the findings demonstrate that cortical tracking is a highly flexible neural mechanism during infancy and can be rapidly modulated by structured rhythmic input. Thus, we identify rhythmic experience as a potential pathway through which infants' auditory environment shapes neural speech processing during language development.

Acquiring sequential information is of utmost importance, e.g., for language acquisition in children. Yet, the long-term storage of statistical learning in children is poorly understood. To address this question, 27 seven-year-olds and 28 young adults completed four sessions of visual sequence learning (Year 1). From this sample, 16 seven-year-olds and 20 young adults participated in another four equivalent sessions after a 12-month-delay (Year 2). The first three sessions of each year used stimulus set-1, while the last session used stimulus set-2 to investigate transfer effects. Each session consisted of alternating learning and test phases in a modified artificial grammar learning task. In Year 1, seven-year-olds and adults learned the regularities and showed transfer to stimulus set-2. Both groups retained their final performance level over the one-year-period. In Year 2, children and adults continued to improve with stimulus set-1, but did not show additional transfer gains. Adults overall outperformed children, but transfer effects were indistinguishable between both groups. The present results suggest that long-term memory traces are formed from repeated sequence learning which can be used to generalize sequence rules to new visual input. However, the present study did not provide evidence for a childhood advantage in learning and remembering sequence rules.

Infant environments are rich in rhythms, many of which are social in nature. These rhythms are proposed to play an important role in early communication and interpersonal synchrony. In this cross-sectional electroencephalography (EEG) study with 3- and 6-month-olds (n=31 and n=30, respectively), we examined whether the infant brain tracks the rhythmicity of locomotion-related biological motion in the visual domain and which experiential factors relate to this ability. We found robust neural tracking of biological motion rhythms at both ages, with no effects of age or orientation (upright or inverted). Additionally, we found that caregiver-reported practice of infant carrying/babywearing and caregiver attitudes toward social touch were linked to infant neural tracking of biological motion rhythms, particularly in the inverted condition. Finally, exploratory analyses revealed a lateralisation effect, whereby the left hemisphere processed rightward (vs. leftward) biological motion rhythms more strongly. Our findings suggest that from early on, the infant brain tracks the rhythmicity of whole-body biological motion. Furthermore, caregiver touch-related practices, particularly infant carrying/babywearing, may play a role in infant neural tracking of socially-relevant rhythms.

Perceptual and speech production abilities of children with cochlear implants (CI) are usually tested by word and sentence repetition or naming tests. However, in their daily life they show very heterogeneous language skills. Here, we describe a way of increasing the ecological validity of language assessment, promoting the use of close to real-life listening situations. The setup consists in watching the audio-visual conversation of two individuals. Childrens gaze-switches from one speaker to the other serve as a proxy of their prediction abilities. Moreover, to better understand the basis and the impact of anticipatory behaviour, we also measured childrens ability to understand the dialogue content, their speech perception and memory skills as well as their rhythmic skills. Importantly, we compared children with CI performances with those of an age-matched group of children with NH. While children with CI revealed poorer speech perception and verbal working memory abilities than NH children, there was no difference in gaze anticipatory behaviour. Interestingly, in children with CI only, we found a significant correlation between dialogue comprehension, perceptive skills and gaze anticipatory behaviour. Our results confirm and extend to a conversational context previous findings showing an absence of predictive deficits in children with CI. The current design seems an interesting avenue to provide an accurate and objective estimate of anticipatory language behaviour in a rather ecological conversational context also with young children.

Adults are able to orient their attention between different (often fleeting) sensory cues that present to different senses ("crossmodal attention"), but we cannot assume that this is the case in early life. Here we report the findings of a study in which we probed the presence of tactile to visual crossmodal links in spatial attention using event related potentials (ERP) gathered from the scalp electroencephalograms (EEG) of 5-(n = 19) and 8-month-old (n = 19) infants. Whilst recording EEG, we presented 5- and 8month-old participants with vibrotactile stimuli on one of their hands, followed by visual stimuli on the same (Congruent) or the opposite (Incongruent) hand, or no touch at all (No probe). During the presentation of these stimuli the infants eyes were oriented centrally. We subtracted No probe trials from Congruent and Incongruent trials to yield visual evoked potentials (VEPs) free from the influence of prior somatosensory processing. Comparably to prior findings in adults, 8-month-olds first negative component of the VEP was enhanced in the hemisphere ipsilateral to the probe when the visual probe was spatially congruent with the tactile cue. No crossmodal effect was observed in the 5-month-olds, indicating developments in the crossmodal coordination of attention in the first year of life.

Young children acquire language in environments where speech is often acoustically degraded, yet little is known about how developing brains adapt to reduced speech intelligibility. Using a combination of eye-tracking and functional near-infrared spectroscopy (fNIRS), we investigated young childrens attentional allocation to a speaking face at varying levels of speech intelligibility and the brain activity supporting this behaviour during development. Infants (8-10 months) and toddlers (27-30 months) viewed videos of a speaker in three conditions: producing clear speech, spectrally degraded (vocoded) speech, and silent (audio muted) speech. Visual attention to the speakers mouth increased when speech was degraded relative to clear speech in both age groups, indicating an early-emerging compensatory strategy. However, this shared behavioural response was supported by brain activity that differed by age. Degraded speech elicited greater recruitment of prefrontal regions associated with effortful listening, particularly in infants, whereas toddlers showed stronger engagement of posterior temporal regions implicated in audiovisual integration. In response to silent speech, there was no evidence for increased visual attention to the mouth compared to the clear speech condition, but there was reduced temporal activation and increased prefrontal brain responses, especially in infants. Together, these findings suggest that experience with audiovisual correspondences and linguistic maturity contribute to a more efficient processing of speech, particularly relevant when speech is degraded. By combining behavioural and neuroimaging measures, this study advances mechanistic accounts of audiovisual speech processing and provides insights relevant to populations experiencing spectrally degraded input, such as children using cochlear implants.

Continuous integration of environmental exteroceptive and internal interoceptive signals is fundamental for perception and adaptive behaviours, yet its developmental trajectory remains poorly understood. Here, we introduced a modified iBEATs paradigm, based on prior work, to investigate cardiac-exteroceptive integration in 3-8-month-old infants. Using behavioural measures of looking time and physiological measures of pupillometry, we found that the ability to detect cardiac-exteroceptive synchrony emerges during the first year of life. Critically, this was evident only when stimuli coincided with systole, the baroreceptor-active phase of the cardiac cycle, supporting central multimodal integration interpretable within a predictive coding framework. Furthermore, individual differences in behavioural sensitivity were accounted for by the degree of autonomic maturation. These findings provide the first evidence for the developmental emergence and mechanisms of cardiac-exteroceptive integration, and establish the modified iBEATs paradigm as a promising tool for assessing interoceptive development in early life.

Effective speech analysis involves deconstructing the acoustic signal into identifiable linguistic units, which depends on the ability to recognize and anticipate temporal patterns within the speech stream. However, these processes may be less efficient in individuals with dyslexia. This study investigated the effects of temporal context and related temporal predictions in dyslexic adult participants and matched control participants, using an auditory oddball task with non-verbal stimuli. Pure tones were presented in sequences, and participants were requested to discriminate the pitch of target stimuli. The temporal intervals between the sounds varied in regularity across the sequences, thereby creating contexts with different levels of temporal predictability. At the end of each sequence, participants were prompted to evaluate the perceived rhythmicity of the sequence and to assess their own performance in the auditory discrimination task. Dyslexic participants demonstrated overall lower accuracy in discriminating target sounds than controls. They also showed reduced influence of the temporal context of the sequences on response times, while controls responded faster in sequences that were temporally more regular and predictable. Additionally, individuals with dyslexia perceived the rhythmicity of sound sequences less accurately, overestimating the temporal regularity in irregular sequences and underestimating it in regular sequences. They also reported lower overall confidence in their ability to perform the task compared to control participants. Altogether, these findings provide converging evidence for altered temporal prediction abilities in dyslexia, which may impact auditory perception and then impair language processing.

This preliminary study was conducted to explore the effects of bilingualism on executive function development in children ages 3-5-years old. Two groups (bilinguals and monolinguals) were recruited across various sites in Southern Alberta. Children were assessed through parent rated executive function using the Behaviour Rating Inventory of Executive Function - Preschool version, a standardized assessment of executive function in children aged 2 years, 0 months through 5 years, 11 months. The questionnaire contains 63 items measuring 5 aspects of executive functioning, inhibit, shift, emotional control, working memory, and plan/organize. Children were also assessed using a battery of executive function tasks, which include the reverse categorization, pictorial Stroop, Dimensional Change Card Sort, backward digit span, and dyadic social play. Results show that bilingual children outperform monolinguals on the emotional control scale, dimensional change card sort and dyadic social play. Despite the controversial literature surrounding bilingualisms impact on executive function, the study reveals support for second language use to improve areas of executive function among young children.

Preterm birth is a common neurodevelopmental condition that can have lasting impacts on cognition, including attention and working memory. Interventions that strengthen these skills in early childhood could support school readiness. Dino Island is a tablet-based intervention that combines process-specific practice of attention and working memory skills with a compensatory component that teaches metacognitive skills to scaffold learning. In this pilot study, we evaluated the feasibility of parent-delivered Dino Island in young children born preterm (N=10), alongside a control group who played educational games (N=12). Both groups were instructed to play 2-3 times per week for approximately 20 minutes over a 12-week period. Attention and working memory on untrained tasks were assessed before and after completing the intervention. Parents provided fidelity data through tracking sheets and participated in exit interviews to offer feedback and identify barriers and facilitators. We found that the Dino Island program was successfully delivered by parents with high fidelity. Attrition was higher in the Dino Island group, likely reflecting the challenges of delivering cognitive remediation in home settings. Comparison of attention and working memory scores on untrained tasks pre- and post-showed practice effects but no specific benefit of Dino Island. However, parent reports suggested behavioral improvements specific to the Dino Island group, noting far-transfer effects where children applied metacognitive strategies in other contexts. Overall, this work shows feasibility and tolerability of Dino Island in young children born preterm. Future research should examine its potential impact on school readiness and longer-term academic outcomes in this population.

Newborns recognise familiar language patterns experienced in utero and discriminate them from unfamiliar ones. It is as yet unclear which neural mechanisms are responsible for such early language-specific behavior. Here we focus on neural speech tracking and test whether it shows language-specific attunement in newborns and one-to-two month olds. Infants listened to infant-directed stories in their native language (Czech) and an unfamiliar language (Russian) while their EEG was recorded. First, we examined whether neural speech tracking differed between infants predominantly exposed to Czech and infants exposed primarily to other languages. Second, we assessed developmental changes by combining these data with a previously collected cohort of newborns, yielding a continuous sample spanning 1-62 days of age. Neural speech tracking was assessed in stimulus-derived delta and theta frequency bands in terms of oscillatory power and accuracy of EEG-to-speech envelope reconstruction using the backward multivariate temporal response functions. Czech-exposed infants had stronger cortical tracking of Czech speech than infants exposed to other languages. Within the Czech-exposed group, native Czech elicited stronger neural tracking than unfamiliar Russian, particularly in the delta band, indicating early language-specific tuning to the prosodic-word structure. Across the combined Czech-exposed sample, this native-language advantage gradually decreased with age, suggesting that neural speech tracking of the slow rhythms undergoes rapid reorganization during the first two months of life. These findings demonstrate that language-specific neural speech tracking is detectable from the earliest weeks of life and is jointly shaped by early, perinatal language experience as well as cognitive maturation.

During typical development, non-social visual object recognition emerges in the first year of life, engaging low-level visual cues and higher-level mechanisms involving inference and prior knowledge. How these processes function in minimally verbal autism (mvASD) remains poorly understood. We studied children with mvASD (n=22, 6-11 years) using touchscreen-based oddball and contour-detection tasks targeting low-level stimuli (e.g. shape and orientation), and mid-level stimuli (e.g. illusory Kanizsa contours and 3D shapes). Pointing and eye-gaze responses were measured. Typically developing children (n=22, 6-12 years) served as a reference group. Accuracy and reaction-time profiles among mvASD participants were heterogeneous across experimental visual tasks and standardized developmental measures. All mvASD participants detected targets in the easiest condition, and approximately half succeeded across low-level tasks. Overall performance declined with increasing visual complexity, consistent with attenuated inference-based processing; communication ability and nonverbal reasoning together accounted for approximately 69% of between-participant variance in visual task performance. Critically, exploratory analyses suggested systematic perception-action dissociations rather than random error. First, the majority of participants who failed to point correctly (n=9) reliably fixated the correct target. Second, in the Kanizsa oddball task, nearly half of successful mvASD participants pointed to local inducers rather than the illusory figure center, unlike TDs. Third, more participants showed within-age-range nonverbal reasoning performance on Ravens colorful progressive matrices when responding by puzzle placement than by pointing. These converging findings challenge interpretations of mvASD performance as reflecting perceptual or cognitive capacity alone, suggesting visual signals may guide action selection differently in mvASD. Lay SummaryMinimally verbal children with autism showed individual differences in visual processing tasks. While developmental measures like communication ability and reasoning skills predicted most of the variation in performance, exploratory observations revealed an intriguing pattern: the same children sometimes succeeded when using their eyes to indicate answers but failed when pointing or performing better when placing puzzle pieces than pointing in a booklet to identical visual display. Several children who correctly detected illusory triangular shapes consistently touched the corner pieces rather than the triangle centers. These patterns suggest that performance depends not only on developmental and visual perceptual abilities, but also on how children are asked to respond. Parents and educators should consider: might a child who fails a pointing-based test succeed with a different response method?

Parents have large genetic and environmental influences on their childrens cognition, behavior, and brain. Previous studies have indicated intergenerational transfer of the behavior of reading. Despite a close coupling between brain and behavior however, the intergenerational transfer of reading-related structural brain networks have not been investigated. Therefore, we investigated its parent-child associations for the first time. We examined how white matter tracts i.e., Arcuate Fasciculus (AF) and Inferior Fronto-Occipital Fasciculus (IFOF), are associated with childrens early reading development from Kindergarten to Grade 3 in 33 families. First, we observed in our sample of children -who all had typical reading skills despite half of them having an increased risk for dyslexia- that fractional anisotropy in bilateral IFOF and right AF correlated with reading development. Second, parent-child correlations were observed for bilateral IFOF but not for AF. Finally, we demonstrated that the relation between childrens IFOF and reading development was largely explained by parental IFOF. The findings preliminarily suggest that white matter organization in IFOF represents a pre-existing protective factor in children at risk, as it is mainly determined by biological parental factors. Large-scale intergenerational, multi-level and longitudinal studies are needed to understand the dynamic interrelations between brain, environment and behavior.

Dyslexia, defined as a specific impairment in decoding the written script, is the most widespread learning difficulty. However, individuals with dyslexia (IDDs) also consistently manifest reduced short-term memory (STM) capacity, typically measured by Digit Span or non-word repetition tasks. In this paper we report two experiments which test the effect of item frequency and the effect of a repeated sequence on the performance in STM tasks in good readers and in IDDs. IDDs performance benefited less from item frequency, revealing poor use of long-term single item statistics. This pattern suggests that the amply reported shorter verbal spans in dyslexia may in fact reflect their impaired sensitivity to items long-term frequency. For repeated sequence learning, we found no significant deficit among IDDs, even when a sensitive paradigm and a robust measure were used.

Visual attention is an important mechanism through which children learn about their environment, and individual differences could substantially shape later development. Eyetracking provides a sensitive and scalable tool for assessing visual attention that has potential for objective assessment of child development, but to date the majority of studies are small and replication attempts are rare. This study investigates the feasibility of a comprehensive eye-tracking assessment of visual attention and introduces a shared data resource for the scientific community. Data from eight eyetracking tasks were collected from 350 term-born (166 females) 18-month-olds recruited as neonates http://www.developingconnectome.org/). Analyses showed expected condition effects for seven of eight tasks (p-values from <.001 to .04), an important indication of replicability. Consistent with some theoretical models of visual attention, structural equation modelling indicated participants performance could be explained by two factors representing social and non-social attention. Comprehensive eye-tracking batteries can objectively measure individual differences in core components of visual attention in large-scale toddlerhood studies. This is the first large-scale comprehensive study to present high-quality normative eye-tracking data from a large task battery in toddlers and make them freely available to the scientific community.

Specific Learning Disorders (SLD), including dyslexia, dyscalculia, and dysgraphia, are associated with deficits in executive functions such as auditory working memory (AWM). This study investigated AWM performance and metacognitive monitoring in adolescents diagnosed with SLD using an auditory delayed-match-to-sample task. Thirty-six participants (18 with SLD and 18 neurotypical controls) were assessed on accuracy, reaction time, and confidence ratings. Adolescents with SLD exhibited reduced sensitivity to auditory intensity differences, slower reaction times, and more conservative decision-making strategies. Drift diffusion modeling revealed lower evidence accumulation rates and wider decision boundaries in the SLD group. Moreover, confidence ratings were less influenced by stimulus differences, particularly among participants with dyslexia. These findings highlight impairments in auditory processing, decision-making, and metacognitive self-monitoring in adolescents with SLD. The results underscore the importance of interventions that address not only linguistic skills but also auditory decision-making and metacognitive strategies to support learning outcomes.