Language, gesture, and the developing brain

Gesture screening in young infants: Highly sensitive to risk factors for communication delay

INTRODUCTION

Children's early language and communication skills are efficiently measured using parent report, for example, communicative development inventories (CDIs). These have scalable potential to determine risk of later language delay, and associations between delay and risk factors such as prematurity and poverty. However, there may be measurement difficulties in parent reports, including anomalous directions of association between child age/socioeconomic status and reported language. Findings vary on whether parents may report older infants as having smaller vocabularies than younger infants, for example.

METHODS

We analysed data from the UK Communicative Development Inventory (Words and Gestures); UK-CDI (W&G) to determine whether anomalous associations would be replicated in this population, and/or with gesture. In total 1204 families of children aged 8-18 months (598 girls, matched to UK population for income, parental education and ethnicity as far as possible) completed Vocabulary and Gesture scales of the UK-CDI (W&G).

RESULTS

Overall scores on the Gesture scale showed more significant relationships with biological risk factors including prematurity than did Vocabulary scores. Gesture also showed more straightforward relationships with social risk factors including income. Relationships between vocabulary and social risk factors were less straightforward; some at-risk groups reported higher vocabulary scores than other groups.

DISCUSSION

We conclude that vocabulary report may be less accurate than gesture for this age. Parents have greater knowledge of language than gesture milestones, hence may report expectations for vocabulary, not observed vocabulary. We also conclude that gesture should be included in early language scales partly because of its greater, more straightforward association with many risk factors for language delay.

WHAT THIS PAPER ADDS

What is already known on the subject We already know that it is possible to measure children's early communicative skills using parent-completed inventories (Communicative Development Inventories, CDIs) and that some aspects of early communication can predict which children are likely to go on to have long-lasting communicative development difficulties. We also know that most uses of CDIs include only vocabulary, not early gesture. In addition, child-related and family-related variables such as prematurity, family history of language disorder and socioeconomic status may be related to communication development. What this paper adds to existing knowledge We looked at a large sample (N = approx. 1200) of families representative of the UK population with an infant aged 8 through 18 months and asked them about their infant's comprehension and production vocabulary as well as their early gesture skills. Gesture was more closely related to possible risk factors for communication development difficulties, for example, family history of communication difficulties, prematurity and multiple birth status. Vocabulary was only related in a straightforward way to family history and had complex relationships to socioeconomic differences. Families with different economic backgrounds may approach questions about their child's development in different ways. What are the potential or actual clinical implications of this work? We suggest that clinicians need to ensure that not only vocabulary but also gesture ability is assessed when looking at very early communication skills. We also suggest that gesture may be more predictive of later communicative development difficulties, and that clinicians need to be sure that parents are clear on how vocabulary questions are asked and what exactly is required of them in answering these types of questions.

Forms and Functions of Gestures in Preverbal 12- to 15-Months Old Infants

Speech and co-speech gestures always go hand in hand. Whether we find the precursors of these co-speech gestures in infants before they master their native language still remains an open question. Except for deictic gestures, there is little agreement on the existence of iconic, non-referential and conventional gestures before children start producing their first words. Here, we bridge this knowledge gap by leveraging an ethological method already established for describing speech independent gestures in nonhuman primates, to analyze the spontaneous gestures produced by infants when interacting with their caregivers. We manually annotated video recordings of infant-caregiver interactions (26 h) from the CHILDES platform, to describe the gesture forms, types and functions in six infants from 12 to 15 months of age. We describe 62 gesture forms in the preverbal repertoire. These were categorized into deictic, iconic, non-referential and conventional gesture types, similar to co-speech gesture types. We also find that the type-function relation of preverbal gestures map similarly to type-meaning relation of co-speech gestures. Taken together, our results illustrate linguistic properties of infant gestures in the absence of speech, suggesting them to be precursors of co-speech gestures.

Healthcare providers' perceptions of infant physical activity and communication

BACKGROUND

Healthcare providers (HPs) play a critical role in disseminating information about infant health and development. Two key developmental areas for infants are physical activity (PA) and communication. Few studies have examined HPs views of these topics. Thus, HPs may need support to promote these early development outcomes in infants. Thus, the study explored HPs' perceptions of infant PA and communication.

METHODS

A total of 13 HPs with a wide variety of backgrounds were recruited. Zoom semi-structured interviews were based on the Health Belief Model. Deductive content analysis was utilized to analyze data.

RESULTS

HPs knew little about PA guidelines. HPs were concerned about an infant's PA because of limited playtime and tummy time. Most HPs advised parents on PA and motor development milestones, with crawling, walking, and tummy time. HPs also wanted to learn about PA measurement tools. PA promotion was hindered by parents' busy schedules, lack of time, and language barriers. Most HPs advised parents on verbal and nonverbal communication. Many HPs were unfamiliar with communication assessment methods and wanted to learn more.

CONCLUSIONS

HPs had limited knowledge about PA guidelines and communication measurement tools. Efforts are needed to identify easily accessible ways to educate HPs that could be disseminated to parents.

Comparing the productive vocabularies of grey parrots (Psittacus erithacus) and young children

Due to their outstanding ability of vocal imitation, parrots are often kept as pets. Research has shown that they do not just repeat human words. They can use words purposefully to label objects, persons, and animals, and they can even use conversational phrases in appropriate contexts. So far, the structure of pet parrots' vocabularies and the difference between them and human vocabulary acquisition has been studied only in one individual. This study quantitatively analyses parrot and child vocabularies in a larger sample using a vocabulary coding method suitable for assessing the vocabulary structure in both species. We have explored the composition of word-like sounds produced by 21 grey parrots (Psittacus erithacus) kept as pets in Czech- or Slovak-speaking homes, and compared it to the composition of early productive vocabularies of 21 children acquiring Czech (aged 8-18 months), who were matched to the parrots by vocabulary size. The results show that the 'vocabularies' of talking grey parrots and children differ: children use significantly more object labels, activity and situation labels, and emotional expressions, while parrots produce significantly more conversational expressions, greetings, and multiword utterances in general. These differences could reflect a strong link between learning spoken words and understanding the underlying concepts, an ability seemingly unique to human children (and absent in parrots), but also different communicative goals of the two species.

Impaired motor skills and proprioceptive function in Mandarin-speaking children with developmental language disorder

This study examined proprioceptive acuity and its relationship with motor function in Mandarin-speaking children with and without developmental language disorder (DLD). Fifteen children aged 9-12 years with DLD and 15 age- and sex-matched typically developing (TD) children participated in this study. Children's motor function was assessed using the second edition of the Movement Assessment Battery for Children (MABC-2). Their proprioceptive acuity was measured based on the absolute error (i.e., proprioceptive bias) and variable error (i.e., proprioceptive precision) when performing joint position matching tasks. Compared with the TD group, the DLD group exhibited impaired motor function and poorer proprioceptive acuity, as evidenced by the lower scores on the MABC-2 and the higher rates of absolute and variable errors in the joint position matching tasks. A significant association between the proprioceptive bias (absolute error) and the MABC-2 total score was also observed in the combined cohort of children with and without DLD. We conclude that DLD is associated with proprioceptive dysfunction.

Infants' pointing at nine months is associated with maternal sensitivity but not vocabulary

Infants often start pointing toward the end of their first year of life. Pointing shows a strong link to language, perhaps because parents label what infants point to. In the present study, we tested whether 9-month-olds' pointing was related to parental sensitivity and concurrent and subsequent vocabulary scores. Observations were made of 88 9-month-old infants in free-play situations with their mothers. Less than half the infants produced at least one index-finger point. The mothers' reactions to their infants' behaviour were coded for sensitivity. The mothers of the infants who pointed were less directing and responded more contingently than the mothers of the infants who did not point. However, there was no difference in vocabulary scores of pointers and non-pointers, either concurrently or at 12 and 18 months of age. These results could mean that parents' reactions play an important role in shaping pointing to be communicative.

Information-Restricted Neural Language Models Reveal Different Brain Regions' Sensitivity to Semantics, Syntax, and Context

A fundamental question in neurolinguistics concerns the brain regions involved in syntactic and semantic processing during speech comprehension, both at the lexical (word processing) and supra-lexical levels (sentence and discourse processing). To what extent are these regions separated or intertwined? To address this question, we introduce a novel approach exploiting neural language models to generate high-dimensional feature sets that separately encode semantic and syntactic information. More precisely, we train a lexical language model, GloVe, and a supra-lexical language model, GPT-2, on a text corpus from which we selectively removed either syntactic or semantic information. We then assess to what extent the features derived from these information-restricted models are still able to predict the fMRI time courses of humans listening to naturalistic text. Furthermore, to determine the windows of integration of brain regions involved in supra-lexical processing, we manipulate the size of contextual information provided to GPT-2. The analyses show that, while most brain regions involved in language comprehension are sensitive to both syntactic and semantic features, the relative magnitudes of these effects vary across these regions. Moreover, regions that are best fitted by semantic or syntactic features are more spatially dissociated in the left hemisphere than in the right one, and the right hemisphere shows sensitivity to longer contexts than the left. The novelty of our approach lies in the ability to control for the information encoded in the models' embeddings by manipulating the training set. These "information-restricted" models complement previous studies that used language models to probe the neural bases of language, and shed new light on its spatial organization.

A protocol for a randomized-controlled trial to investigate the effect of infant sign training on the speech-language development in young children born with cleft palate

BACKGROUND

Children born with a cleft palate with or without cleft lip (CP ± L) are known to be at risk for speech-language disorders that impact educational and social-emotional growth. It is hypothesized that speech-language intervention delivered before the age of 3 years could decrease the impact of CP ± L on speech-language development. Infant sign training in combination with verbal input expands the natural communication of young children including multimodal speech-language input (i.e., verbal and manual input) via caregivers who act as co-therapists.

AIMS

To determine the effectiveness of infant sign training in 1-year-old children with CP ± L by comparing different interventions.

METHODS & PROCEDURES

This is a two-centre, randomized, parallel-group, longitudinal, controlled trial. Children are randomized to either an infant sign training group (IST group), a verbal training group (VT group) or no intervention control group (C group). Caregivers of children who are assigned to the IST group or VT group will participate in three caregiver training meetings to practise knowledge and skills to stimulate speech-language development. Outcome measures include a combination of questionnaires, language tests and observational analyses of communicative acts.

OUTCOMES & RESULTS

It is hypothesized that speech-language development of children with CP ± L will benefit more from IST compared with VT and no intervention. Additionally, the number and quality of communicative acts of both children and caregivers are expected to be higher after IST.

CONCLUSIONS & IMPLICATIONS

This project will contribute to the development of evidence-based clinical practice guidelines regarding early speech-language intervention in children with CP ± L under the age of 3 years.

WHAT THIS PAPER ADDS

What is already known on the subject Children with CP ± L are known to be at risk for speech-language delays that impact educational and social emotional growth. Given the limited scientific prove of the impact of early speech-language intervention, no standardized clinical practice guidelines are available yet for children with CP ± L under the age of 3 years. Early intervention in this population mostly focuses on improving verbal input via caregivers or professionals without including a multimodal language input. A growing scientific interest has been seen in the use of infant signs to support speech-language development and caregiver-child interaction in typically developing children and children with developmental delays. What this study adds to existing knowledge No evidence is yet available for the effectiveness and feasibility of early intervention based on infant sign training in combination with verbal input to improve speech-language skills in young children with CP ± L. The current project will investigate the effect of infant sign training on the speech-language development in this population. Outcome measures are compared with those of two control groups: verbal training only and no intervention. It is hypothesized that infant signs may support the intelligibility of verbal utterances produced by children with CP ± L. Improving children's intelligibility may increase the opportunities for these children to engage in early, frequent and high-quality interactions with their caregivers resulting in a richer social and linguistic environment. As a result, infant sign training may result in better speech-language skills compared with the control interventions. What are the potential or actual clinical implications of this work? If providing early intervention based on infant sign training is effective, there is the potential for improved speech-language outcomes in early childhood, resulting in increased speech intelligibility, increased well-being of the child and family and less need for speech-language therapy on the long-term. This project will contribute to the development of evidence-based clinical practice guidelines regarding early speech-language intervention in children with CP ± L under the age of 3 years.

Narrative Abilities at Age 3 Are Associated Positively With Gesture Accuracy but Negatively With Gesture Rate

PURPOSE

Though the frequency of gesture use by infants has been related to the development of different language abilities in the initial stages of language acquisition, less is known about whether this frequency (or "gesture rate") continues to correlate with language measures in later stages of language acquisition, or whether the relation to language skills also depends on the accuracy with which such gestures are produced (or reproduced). This study sets out to explore whether preschoolers' narrative abilities are related to these two variables, namely, gesture rate and gesture accuracy.

METHOD

A total of 31 typically developing 3- to 4-year-old children participated in a multimodal imitation task, a context-based gesture elicitation task, and a narrative retelling task.

RESULTS

Results showed that there was a significant positive correlation between the children's narrative scores and their gesture accuracy scores, whereas higher rates of gesture use did not correlate with higher levels of narrative skill. Further multimodal regression analysis confirmed that gesture accuracy was a positive predictor of narrative performance, and moreover, showed that gesture rate was a negative predictor.

CONCLUSIONS

The fact that both gesture accuracy and gesture rate are strongly and differently linked to oral language abilities supports the claim that language and gesture are highly complex systems, and that complementary measures of gesture performance can help us assess with greater granularity the relationship between gesture and language development. These findings highlight the need to use gesture during clinical assessments as an informative indicator of language development and suggest that future research should further investigate the value of multimodal programs in the treatment of language and communication disorders.

A Preliminary Longitudinal Study on Infant-Directed Speech (IDS) Components in the First Year of Life

Infant-directed speech (IDS) is an essential factor of mother–infant interaction and facilitates early language processing and word learning during dyadic interactions. This study aimed to longitudinally investigate emotional and prosodic components of IDS in the first year of life by analyzing children’s responses to the different prosodic trends that mothers use during the observation of mother–child interactions. Seventeen mothers and infants were recruited for this study during their first hospitalization. The study involved observing communication changes in face-to-face interactions between the mother and child at three, six, and nine months after the child’s birth. We analyzed the relationship between gaze direction, smiling, speech speed, and clarity. The results showed that the IDS differs in production when compared to the age of the child; at only nine months, there is high intensity. The same is evident from the results related to the elocution velocity. The verbal sensitivity of the mother and the ability to tune in to the affective states of the child, especially at nine months, can predict the child’s understanding of future language.

Are palm reversals the pronoun reversals of sign language? Evidence from a fingerspelling task

Acquisition of pronominal forms by children with autism spectrum disorder (ASD) continues to garner significant attention due to the unusual ways that such children produce and comprehend them. In particular, pronoun reversal errors (e.g., using the 2nd-person pronoun "you" to refer to oneself) have been noted in the speech of children with ASD since the very first report of the disorder. In more recent years, investigations of the signing of deaf children with ASD have documented a different phenomenon: palm orientation reversals, such that signs typically produced with an outward-facing palm are produced with the palm towards the signer, or vice versa. At the same time, true pronoun reversals have yet to be documented in the signing of deaf children on the autism spectrum. These two curious facts have led us to ask if there is evidence that palm orientation reversals in signed languages and pronoun reversals in spoken languages could be surface manifestations of the same underlying differences present in ASD. In this paper we seek to establish whether there is evidence for such an analogy, by comparing the ages at which the two phenomena appear in both typically-developing (TD) children and those with ASD, the frequency and consistency with which they appear, and their relationships with other linguistic and cognitive skills. Data are presented from a fingerspelling task given to a sample of 17 native-signing children with ASD and 24 native-signing TD children. We conclude that there are provocative parallels between pronoun reversals in spoken languages and palm reversals in signed languages, though more research is needed to definitively answer these questions.

Up right, not right up: Primacy of verticality in both language and movement

When describing motion along both the horizontal and vertical axes, languages from different families express the elements encoding verticality before those coding for horizontality (e.g., going up right instead of right up). In light of the motor grounding of language, the present study investigated whether the prevalence of verticality in Path expression also governs the trajectory of arm biological movements. Using a 3D virtual-reality setting, we tracked the kinematics of hand pointing movements in five spatial directions, two of which implied the vertical and horizontal vectors equally (i.e., up right +45° and bottom right −45°). Movement onset could be prompted by visual or auditory verbal cues, the latter being canonical in French (“en haut à droite”/up right) or not (“à droite en haut”/right up). In two experiments, analyses of the index finger kinematics revealed a significant effect of gravity, with earlier acceleration, velocity, and deceleration peaks for upward (+45°) than downward (−45°) movements, irrespective of the instructions. Remarkably, confirming the linguistic observations, we found that vertical kinematic parameters occurred earlier than horizontal ones for upward movements, both for visual and congruent verbal cues. Non-canonical verbal instructions significantly affected this temporal dynamic: for upward movements, the horizontal and vertical components temporally aligned, while they reversed for downward movements where the kinematics of the vertical axis was delayed with respect to that of the horizontal one. This temporal dynamic is so deeply anchored that non-canonical verbal instructions allowed for horizontality to precede verticality only for movements that do not fight against gravity. Altogether, our findings provide new insights into the embodiment of language by revealing that linguistic path may reflect the organization of biological movements, giving priority to the vertical axis.

Quantitative MRI reveals differences in striatal myelin in children with DLD

Developmental language disorder (DLD) is a common neurodevelopmental disorder characterised by receptive or expressive language difficulties or both. While theoretical frameworks and empirical studies support the idea that there may be neural correlates of DLD in frontostriatal loops, findings are inconsistent across studies. Here, we use a novel semiquantitative imaging protocol - multi-parameter mapping (MPM) - to investigate microstructural neural differences in children with DLD. The MPM protocol allows us to reproducibly map specific indices of tissue microstructure. In 56 typically developing children and 33 children with DLD, we derived maps of (1) longitudinal relaxation rate R1 (1/T1), (2) transverse relaxation rate R2* (1/T2*), and (3) Magnetization Transfer saturation (MTsat). R1 and MTsat predominantly index myelin, while R2* is sensitive to iron content. Children with DLD showed reductions in MTsat values in the caudate nucleus bilaterally, as well as in the left ventral sensorimotor cortex and Heschl's gyrus. They also had globally lower R1 values. No group differences were noted in R2* maps. Differences in MTsat and R1 were coincident in the caudate nucleus bilaterally. These findings support our hypothesis of corticostriatal abnormalities in DLD and indicate abnormal levels of myelin in the dorsal striatum in children with DLD.

Are control processes domain-general? A replication of 'To adapt or not to adapt? The question of domain-general cognitive control' (Kan et al. 2013)

Conflict and conflict adaptation are well-studied phenomena in experimental psychology. Standard tasks investigating causes and outcomes of conflict during information processing include the Stroop, the Flanker and the Simon task. Interestingly, recent research efforts have moved toward investigating whether conflict in one task domain influences information processing in another task domain, typically referred to as cross-task conflict adaptation. These transfer effects are of central importance for theories about our cognitive architecture, as they are interpreted as pointing towards domain-general cognitive mechanisms. Given the importance of these cross-task transfer effects, the current paper targets at replicating one of the key findings. Specifically, Kan et al. (Kan et al. 2013 Cognition 129, 637-651) showed that reading syntactically ambiguous sentences result in processing adjustments in subsequent Stroop trials. This result is in line with the idea that conflict monitoring works in a domain overarching manner. The present paper presents two replication studies: (i) exact replication: identical sentence-reading task intermixed with stimulus-based Stroop task and (ii) conceptual replication: identical sentence-reading task intermixed with response-based Stroop task. Power calculations were based on the original paper. Both experiments were pre-registered. Despite the experiments being closely designed according to the original study, there was no evidence supporting the hypothesis regarding cross-domain conflict adaptation.

A juvenile locomotor program promotes vocal learning in zebra finches

The evolution and development of complex, learned motor skills are thought to be closely associated with other locomotor movement and cognitive functions. However, it remains largely unknown how different neuromuscular programs may interconnect during the protracted developmental process. Here we use a songbird to examine the behavioral and neural substrates between the development of locomotor movement and vocal-motor learning. Juvenile songbirds escalate their locomotor activity during the sensitive period for vocal learning, followed by a surge of vocal practice. Individual variability of locomotor production is positively correlated with precision of tutor imitation and duration of multi-syllable sequences. Manipulation of juvenile locomotion significantly impacts the precision of vocal imitation and neural plasticity. The locomotor program developed during the sensitive period of vocal learning may enrich the neural substrates that promote the subsequent development of vocal learning.

Parents of young infants report poor mental health and more insensitive parenting during the first Covid-19 lockdown

BACKGROUND

The Covid-19 pandemic has put an unprecedented pressure on families with children. How parents were affected by the first Covid-19 lockdown during the early postpartum period, an already challenging period for many, is unknown.

AIM

To investigate the associations between Covid-19 related stress, mental health, and insensitive parenting practices in mothers and fathers with young infants during the first Dutch Covid-19 lockdown.

METHODS

The Dutch Covid-19 and Perinatal Experiences (COPE-NL) study included 681 parents of infants between 0 and 6 months (572 mothers and 109 fathers). Parents filled out online questionnaires about Covid-19 related stress, mental health (i.e. anxiety and depressive symptoms), and insensitive parenting. Hierarchical regression models were used to analyze the data.

RESULTS

Parents of a young infant reported high rates of Covid-19 related stress, with higher reported stress in mothers compared to fathers. Additionally, the percentages of mothers and fathers experiencing clinically meaningful mental health symptoms during the pandemic were relatively high (mothers: 39.7% anxiety, 14.5% depression; fathers: 37.6% anxiety, 6.4% depression). More Covid-19 related stress was associated with more mental health symptoms in parents and increased insensitive parenting practices in mothers.

CONCLUSIONS

The results emphasize the strain of the pandemic on young fathers' and mothers' mental health and its potential negative consequences for parenting. As poor parental mental health and insensitive parenting practices carry risk for worse child outcomes across the lifespan, the mental health burden of the Covid-19 pandemic might not only have affected the parents, but also the next generation.

A model for using developmental science to create effective early intervention programs and technologies to improve children's developmental outcomes

Children born with a variety of environmental or medical risk factors may exhibit delays in global development. Very often, such delays are identified at preschool or school age, when children are severely overdue for effective early interventions that can alleviate the delays. This chapter proposes a conceptual model of child development to inform the creation of interventions and rehabilitative technologies that can be provided very early in development, throughout the first year of life, to optimize children's future developmental outcomes. The model suggests that early sensorimotor skills are antecedent and foundational for future motor, cognitive, language, and social development. As an example, this chapter describes how children's early postural control and exploratory movements facilitate the development of future object exploration behaviors that provide enhanced opportunities for learning and advance children's motor, cognitive, language, and social development. An understanding of the developmental pathways in the model can enable the design of effective intervention programs and rehabilitative technologies that target sensorimotor skills in the first year of life with the goal of minimizing or ameliorating the delays that are typically identified at preschool or school age. Specific examples of early interventions and rehabilitative technologies that have effectively advanced children's motor and cognitive development by targeting early sensorimotor skills and behaviors are provided.

Moderating Effects of Early Pointing on Developmental Trajectories of Word Comprehension and Production

The present study investigated the moderating role of early communicative pointing on the developmental trends of word comprehension and production over the second year of life. Seventy-seven infants were involved in an experimental pointing task (T-POINT) in sessions at 9 and 12 months, and the MB-CDI questionnaire was filled in by their parents at 15, 18 and 24 months. Based on the age at which the infants were seen to use pointing, they were classified into three groups: the ‘Early’ pointers, who first pointed during the 9-month session; the ‘Typical’ pointers, who first pointed in the 12-month session; and the ‘Late’ pointers, who never pointed in either of the sessions. Using multilevel modelling, we traced the developmental trajectories and individual differences for the two lexical domains of word comprehension and production according to the three pointing groups. The main results showed that compared to the Typical pointers: (i) the Early pointers were faster for word comprehension development, and were similar for word production; (ii) the Late pointers showed lexical delay before 18 months for word comprehension, and between 18 and 24 months for word production. These data are discussed in light of the different roles of early pointing on receptive compared to expressive vocabulary development.

Can Gestures Give us Access to Thought? A Systematic Literature Review on the Role of Co-thought and Co-speech Gestures in Children with Intellectual Disabilities

This systematic review analyzes the differential use of gestures in learning by children with intellectual disability (ID) compared to typically developing ones (TD). Eleven studies published between 2000 and 2020 fulfilled the inclusion criteria (N = 364 participants). The results identify three key elements: (1) Children with ID accompany their spoken language with more gestures than TD children; (2) Specifically, they produce more iconic gestures that provide access to the conceptualization process and understanding in students with ID; (3) Children with ID rely on gesture more than TD children to carry meaning (i.e., produce unimodal gestural utterances without accompanying speech). Possible implications for teaching and guidelines for future research are proposed.

Hand Movements in Communicative and Noncommunicative Situations in Very Young Infants: A Preliminary Study

As a step toward understanding the developmental relationship between handedness and language lateralization, this longitudinal study investigated how infants (N = 21) move their hands in noncommunicative and communicative situations at 2 weeks and at 3 months of age. The authors looked at whether left-right asymmetry in hand movements and in duration of self-touch appeared across conditions and whether the direction of asymmetry depended on the communicative nature of the situation. The authors found that asymmetries appeared less consistently than suggested in literature and did not only depend on the communicative nature of the situation. Instead, hand activity and self-touch patterns depended on age, the presence of the mother, the degree of novelty of the situation, and the presence of an object. The results partly support previous studies that pointed out an early differentiation of communicative hand movements versus noncommunicative ones in infants. It is in terms of the amount of global hand activity, rather than in those of the laterality of hand movements that this differentiation emerged in this study. At 3 months, infants moved their hands more in the communicative conditions than in the noncommunicative conditions and this difference appeared as a tendency already at 2 weeks of age.

Characterizing the Richness of Maternal Input for Word Learning in Neurogenetic Disorders

Promoting language abilities, including early word learning, in children with neurogenetic disorders with associated language disorders, such as Down syndrome (DS) and fragile X syndrome (FXS), is a main concern for caregivers and clinicians. For typically developing children, the quality and quantity of maternal language input and maternal gesture use contributes to child word learning, and a similar relation is likely present in DS and FXS. However, few studies have examined the combined effect of maternal language input and maternal gesture use on child word learning. We present a multidimensional approach for coding word-referent transparency in naturally occurring input to children with neurogenetic disorders. We conceptualize high-quality input from a multidimensional perspective, considering features from linguistic, interactive, and conceptual dimensions simultaneously. Using case examples, we highlight how infrequent the moments of word-referent transparency are for three toddlers with DS during play with their mothers. We discuss the implications of this multidimensional framework for children with DS and FXS, including the clinical application of our approach to promote early word learning for these children.

Gender differences in early stages of language development. Some evidence and possible explanations

It is a common feeling that girls speak earlier than boys; however, whether or not there are gender differences in early language acquisition remains controversial. The present paper aims to review the research on gender effects in early language acquisition and development, to determine whether, and from which age, an advantage for girls does eventually emerge. The focus is on the production of actions and communicative gestures, and early lexical comprehension and production, by girls and boys. The data from various studies that were conducted with direct and indirect tools suggest that some gender differences in actions, gesture, and lexical development depend on the interactions of different factors. Studies differ in terms of age ranges, sample sizes, and tools used, and the girl advantage is often slight and/or not evident at all ages considered. Statistical significance for gender differences appears to depend on the greater individual variability among boys, with respect to girls, which results in a greater number of boys classified as children with poor verbal ability. Biological (e.g., different maturational rates), neuropsychological (e.g., different cognitive strategies in solving tasks), and cultural (e.g., differences in the way parents relate socially to boys and girls) factors appear to interact, to create feedback loops of mutual reinforcement.

Learning blossoms: Caregiver-infant interactions in an outdoor garden setting

Plants provide unique opportunities for learning by engaging all human senses. Recent laboratory studies have shown that infants use a combination of behavioural avoidance and social learning strategies to safely learn about plant properties from adults. Here we investigate how infants and their caregivers interact with plants in an outdoor garden as a first step towards examining the operation of these social learning processes in naturalistic settings. We focus on two specific aspects of spontaneous infant-caregiver interactions with plants: olfactory and touch behaviours. Additionally, we look at whether infants' and caregivers' prior knowledge of the plants in our study influences infants' behaviour. Our results showed a multifaceted connection between infants' and caregivers' previous experience with the plants and their olfactory and touch behaviours. First, infants tended to touch and smell the plants after their caregivers did, and this appeared to be independent of whether infants had seen the plant before. Second, infants systematically engaged in some of the same types of olfactory and touch behaviours their caregiver displayed towards plants. Finally, infants whose caregivers were given more information about the plants in the study showed fewer touch behaviours, but no difference in olfactory behaviours. These findings bolster the previous laboratory studies of plant learning early in life, highlighting the importance of olfactory behaviours, and underscoring the benefits of using ecological observations to explore unique aspects of human development.

Oral Motor and Gesture Abilities Independently Associated With Preschool Language Skill: Longitudinal and Concurrent Relationships at 21 Months and 3-4 Years

Purpose Early motor abilities (gesture, oral motor, and gross/fine skills) are related to language abilities, and this is not due to an association with cognitive or symbolic abilities: Oral motor skills are uniquely associated with language abilities at 21 months of age. It is important to determine whether this motor-language relationship continues beyond the earliest stage of language development to understand language acquisition better and better predict which children may have lasting language difficulties. Method In this longitudinal study, we assessed language comprehension and production, oral motor skill, gross/fine motor skill, and meaningless manual gesture at ages 3 years (N = 89) and 4 years (N = 71), comparing the contribution of motor skill and earlier (at 21 months of age) language ability. We also examined covariates: nonverbal cognitive ability, socioeconomic status, and stimulation in the home as measured on the Home Screening Questionnaire. Results Motor abilities continue to have a significant relationship with language abilities independent of other factors in the preschool years. Meaningless manual gesture ability, gross/fine motor skill, and oral motor skill were still associated with language skill at 3 years of age; these relationships are not explained by the contribution of cognitive abilities or earlier language abilities. Conclusions Relationships between early motor skill and language development persist into preschool years and are not explained by other cognitive or home factors, nor by a relationship with earlier language ability. This finding should lead to a better understanding of the origins of language abilities.

Mechanisms for handling nested dependencies in neural-network language models and humans

Recursive processing in sentence comprehension is considered a hallmark of human linguistic abilities. However, its underlying neural mechanisms remain largely unknown. We studied whether a modern artificial neural network trained with "deep learning" methods mimics a central aspect of human sentence processing, namely the storing of grammatical number and gender information in working memory and its use in long-distance agreement (e.g., capturing the correct number agreement between subject and verb when they are separated by other phrases). Although the network, a recurrent architecture with Long Short-Term Memory units, was solely trained to predict the next word in a large corpus, analysis showed the emergence of a very sparse set of specialized units that successfully handled local and long-distance syntactic agreement for grammatical number. However, the simulations also showed that this mechanism does not support full recursion and fails with some long-range embedded dependencies. We tested the model's predictions in a behavioral experiment where humans detected violations in number agreement in sentences with systematic variations in the singular/plural status of multiple nouns, with or without embedding. Human and model error patterns were remarkably similar, showing that the model echoes various effects observed in human data. However, a key difference was that, with embedded long-range dependencies, humans remained above chance level, while the model's systematic errors brought it below chance. Overall, our study shows that exploring the ways in which modern artificial neural networks process sentences leads to precise and testable hypotheses about human linguistic performance.

Rate of Communicative Gestures and Developmental Outcomes in Toddlers With and Without Autism Spectrum Disorder During a Home Observation

Purpose Most toddlers with autism spectrum disorder and other developmental delays receive early intervention at home and may not participate in a clinic-based communication evaluation. However, there is limited research that has prospectively examined communication in very young children with and without autism in a home-based setting. This study used granular observational coding to document the communicative acts performed by toddlers with autism, developmental delay, and typical development in the home environment. Method Children were selected from the archival database of the FIRST WORDS Project (N = 211). At approximately 20 months of age, each child participated in everyday activities with a caregiver during an hour-long, video-recorded, naturalistic home observation. Inventories of unique gestures, rates per minute, and proportions of types of communicative acts and communicative functions were coded and compared using a one-way analysis of variance. Concurrent and prospective relationships between rate of communication and measures of social communication, language development, and autism symptoms were examined. Results A total of 40,738 communicative acts were coded. Children with autism, developmental delay, and typical development used eight, nine, and 12 unique gestures on average, respectively. Children with autism used deictic gestures, vocalizations, and communicative acts for behavior regulation at significantly lower rates than the other groups. Statistically significant correlations were observed between rate of communication and several outcome measures. Conclusion Observation of social communication in the natural environment may improve early identification of children with autism and communication delays, complement clinic-based assessments, and provide useful information about a child's social communication profile and the family's preferred activities and intervention priorities. Supplemental Material https://doi.org/10.23641/asha.14204522.

The Gestures in 2-4-Year-Old Children With Autism Spectrum Disorder

Deficits in gestures act as early signs of impairment in social interaction (SI) and communication in children with autism spectrum disorder (ASD). However, the pieces of literature on atypical gesture patterns in ASD children are contradictory. This investigation aimed to explore the atypical gesture pattern of ASD children from the dimensions of quantity, communicative function, and integration ability; and its relationship with social ability and adaptive behavior. We used a semi-structured interactive play to evaluate gestures of 33 ASD children (24–48 months old) and 24 typically developing (TD) children (12–36 months old). And we evaluated the social ability, adaptive behavior, and productive language of ASD and TD children by using the Adaptive Behavior Assessment System version II (ABAS-II) and Chinese Communication Development Inventory (CCDI). No matter the total score of CCDI was corrected or not, the relative frequency of total gestures, behavior regulation (BR) gestures, SI gestures, and joint attention (JA) gestures of ASD children were lower than that of TD children, as well as the proportion of JA gestures. However, there was no significant group difference in the proportion of BR and SI gestures. Before adjusting for the total score of CCDI, the relative frequency of gestures without vocalization/verbalization integration and vocalization/verbalization-integrated gestures in ASD children was lower than that in TD children. However, after matching the total score of CCDI, only the relative frequency of gestures without vocalization/verbalization integration was lower. Regardless of the fact that the total score of CCDI was corrected or not, the relative frequency and the proportion of eye-gaze-integrated gestures in ASD children were lower than that in TD children. And the proportion of gestures without eye-gaze integration in ASD children was higher than that in TD children. For ASD children, the social skills score in ABAS-II was positively correlated with the relative frequency of SI gesture and eye-gaze-integrated gestures; the total score of ABAS-II was positively correlated with the relative frequency of total gestures and eye-gaze-integrated gestures. In conclusion, ASD children produce fewer gestures and have deficits in JA gestures. The deficiency of integrating eye gaze and gesture is the core deficit of ASD children’s gesture communication. Relatively, ASD children might be capable of integrating vocalization/verbalization into gestures. SI gestures and the ability to integrate gesture and eye gaze are related to social ability. The quantity of gestures and the ability to integrate gesture with eye gaze are related to adaptive behavior.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier ChiCTR1800019679.

Parent-child interaction during the first year of life in infants at elevated likelihood of autism spectrum disorder

Autism spectrum disorder (ASD) likely emerges from a complex interaction between pre-existing neurodevelopmental vulnerabilities and the environment. The interaction with parents forms a key aspect of an infant's social environment, but few prospective studies of infants at elevated likelihood (EL) for ASD (who have an older sibling with ASD) have examined parent-child interactions in the first year of life. As part of a European multisite network, parent-child dyads of free play were observed at 5 months (62 EL infants, 47 infants at typical likelihood (TL)) and 10 months (101 EL siblings, 77 TL siblings). The newly-developed Parent-Infant/Toddler Coding of Interaction (PInTCI) scheme was used, focusing on global characteristics of infant and parent behaviors. Coders were blind to participant information. Linear mixed model analyses showed no significant group differences in infant or parent behaviors at 5 or 10 months of age (all ps≥0.09, d≤0.36), controlling for infant's sex and age, and parental educational level. However, without adjustments, EL infants showed fewer and less clear initiations at 10 months than TL infants (p = 0.02, d = 0.44), but statistical significance was lost after controlling for parental education (p = 0.09, d = 0.36), which tended to be lower in the EL group. Consistent with previous literature focusing on parent-infant dyads, our findings suggest that differences between EL and TL dyads may only be subtle during the first year of life. We discuss possible explanations and implications for future developmental studies.

Multimodal representational gestures in the transition to multi-word productions

The aim of this study was to analyze the use of representational gestures from a multimodal point of view in the transition from one-word to multi-word constructions. Twenty-one Spanish-speaking children were observed longitudinally at 18, 21, 24, and 30 months of age. We analyzed the production of deictic, symbolic, and conventional gestures and their coordination with different verbal elements. Moreover, we explored the relationship between gestural multimodal and unimodal productions and independent measures of language development. Results showed that gesture production remains stable in the period studied. Whereas deictic gestures are frequent and mostly multimodal from the beginning, conventional gestures are rare and mainly unimodal. Symbolic gestures are initially unimodal, but between 24 and 30 months of age, this pattern reverses, with more multimodal symbolic gestures than unimodal. In addition, the frequency of multimodal representational gestures at specific ages seems to be positively related to independent measures of vocabulary and morphosyntax development. By contrast, the production of unimodal representational gestures appears negatively related to these measures. Our results suggest that multimodal representational gestures could have a facilitating role in the process of learning to combine meanings for communicative goals.

The rise of languaging

In this paper, we turn to languaging, defined here as activity in which wordings play a part. On such a view, while activity is paramount, people also orient to acts of vocalization as wordings. These physical wordings can be used as tools that shape attending, with recourse to neither mental representations nor symbols that store and transmit information. The view is consistent with macroevolutionary continuity and will be used to challenge appeal to a major evolutionary transition to 'language'. On the languaging view, like many modern social primates, hominins have long undertaken encultured activities. Infants, human and nonhuman, act epistemically and, by so doing, align skills with objects to practice. They develop a 'stance' to pragmatic, goal-directed action. In human ontogenesis, we argue, both epistemic action and the stance-taking are extended by vocalizing. Caregiver-infant coordination enables vocalizing to be integrated with acting, attending, perceiving and managing one's attention. Infants also self-entrain vocalizing through 'babble'. Once the developmental threads unite, social reaching (Bates, 1976) favors a special stance to articulatory gestures (one that allows wordings to be made and heard). Just as in orienting to cultural tools, a child grasps a community's ways-with-wordings. The latter often express abstract relations which we can illustrate with modern non-literate use of reciprocal expressions. In Australian and Pacific languages, reciprocals sustain coordinating that, for speakers, is neither symbolic nor arbitrary. Further, cross-linguistic comparison shows the same 'patchy distribution' of reciprocals that characterizes primate tool use. Of course, we do not deny that, in many language games, people can undertake activity that makes symbolic use of wordings. In modern literate societies, abilities based on social reaching are further extended into skills that use notational practices (e.g. letters, numbers, graphics). This opens up whole new fields or domains of languaging. Yet, ostensive use of symbols is plainly a cultural invention - not a direct legacy of hominin evolution.

Cognitive characteristics of 8- to 10-week-old assistance dog puppies

To characterize the early ontogeny of dog cognition, we tested 168 domestic dog, Canis familiaris, puppies (97 females, 71 males; mean age = 9.2 weeks) in a novel test battery based on previous tasks developed and employed with adolescent and adult dogs. Our sample consisted of Labrador retrievers, golden retrievers and Labrador × golden retriever crosses from 65 different litters at Canine Companions for Independence, an organization that breeds, trains and places assistance dogs for people with disabilities. Puppies participated in a 3-day cognitive battery that consisted of 14 tasks measuring different cognitive abilities and temperament traits such as executive function (e.g. inhibitory control, reversal learning, working memory), use of social cues, sensory discriminations and reactivity to and recovery from novel situations. At 8-10 weeks of age, and despite minimal experience with humans, puppies reliably used a variety of cooperative-communicative gestures from humans. Puppies accurately remembered the location of hidden food for delays of up to 20 s, and succeeded in a variety of visual, olfactory and auditory discrimination problems. They also showed some skill at executive function tasks requiring inhibitory control and reversal learning, although they scored lower on these tasks than is typical in adulthood. Taken together, our results confirm the early emergence of sensitivity to human communication in dogs and contextualize these skills within a broad array of other cognitive abilities measured at the same stage of ontogeny.

The effect of interbrain synchronization in gesture observation: A fNIRS study

INTRODUCTION

Gestures characterize individuals' nonverbal communicative exchanges, taking on different functions. Several types of research in the neuroscientific field have been interested in the investigation of the neural correlates underlying the observation and implementation of different gestures categories. In particular, different studies have focused on the neural correlates underlying gestures observation, emphasizing the presence of mirroring mechanisms in specific brain areas, which appear to be involved in gesture observation and planning mechanisms.

MATERIALS AND METHODS

Specifically, the present study aimed to investigate the neural mechanisms, through the use of functional Near-Infrared Spectroscopy (fNIRS), underlying the observation of affective, social, and informative gestures with positive and negative valence in individuals' dyads composed by encoder and decoder. The variations of oxygenated (O2Hb) and deoxygenated (HHb) hemoglobin concentrations of both individuals were collected simultaneously through the use of hyperscanning paradigm, allowing the recording of brain responsiveness and interbrain connectivity.

RESULTS

The results showed a different brain activation and an increase of interbrain connectivity according to the type of gestures observed, with a significant increase of O2Hb brain responsiveness and interbrain connectivity and a decrease of HHb brain responsiveness for affective gestures in the dorsolateral prefrontal cortex (DLPFC) and for social gestures in the superior frontal gyrus (SFG). Furthermore, concerning the valence of the observed gestures, an increase of O2Hb brain activity and interbrain connectivity was observed in the left DLPFC for positive affective gestures compared to negative ones.

CONCLUSION

In conclusion, the present study showed different brain responses underlying the observation of different types of positive and negative gestures. Moreover, interbrain connectivity calculation allowed us to underline the presence of mirroring mechanisms involved in gesture-specific frontal regions during gestures observation and action planning.

Language Growth in Young Children with Autism: Interactions Between Language Production and Social Communication

Young children with autism spectrum disorder (ASD) present with a broad range of spoken language abilities, as well as delays in precursor skills such as gesture production and joint attention skills. While standardized assessments describe language strengths, the Communication and Symbolic Behavior Scales (CSBS-DP) is a particularly robust measure as it additionally characterizes precise aspects of social communication. This study provides a unique contribution by assessing the interactional effects of CSBS-DP Social Composite performance with early language samples on later language outcomes. Our results indicate that multiple social communication elements significantly interact with early spoken language to predict later language. Our findings also highlight the transactional relationship between early spoken vocabulary and social communication skills that bolster language development growth.

Phonetic Implementation of Prosodic Emphasis in Preschool-Aged Children and Adults: Probing the Development of Sensorimotor Speech Goals

Objective We aimed to investigate the production of contrastive emphasis in French-speaking 4-year-olds and adults. Based on previous work, we predicted that, due to their immature motor control abilities, preschool-aged children would produce smaller articulatory differences between emphasized and neutral syllables than adults. Method Ten 4-year-old children and 10 adult French speakers were recorded while repeating /bib/, /bub/, and /bab/ sequences in neutral and contrastive emphasis conditions. Synchronous recordings of tongue movements, lip and jaw positions, and speech signals were made. Lip positions and tongue shapes were analyzed; formant frequencies, amplitude, fundamental frequency, and duration were extracted from the acoustic signals; and between-vowel contrasts were calculated. Results Emphasized vowels were higher in pitch, intensity, and duration than their neutral counterparts in all participants. However, the effect of contrastive emphasis on lip position was smaller in children. Prosody did not affect tongue position in children, whereas it did in adults. As a result, children's productions were perceived less accurately than those of adults. Conclusion These findings suggest that 4-year-old children have not yet learned to produce hypoarticulated forms of phonemic goals to allow them to successfully contrast syllables and enhance prosodic saliency.

Functional near-infrared spectroscopy in toddlers: Neural differentiation of communicative cues and relation to future language abilities

The toddler and preschool years are a time of significant development in both expressive and receptive communication abilities. However, little is known about the neurobiological underpinnings of language development during this period, likely due to difficulties acquiring functional neuroimaging data. Functional near‐infrared spectroscopy (fNIRS) is a motion‐tolerant neuroimaging technique that assesses cortical brain activity and can be used in very young children. Here, we use fNIRS during perception of communicative and noncommunicative speech and gestures in typically developing 2‐ and 3‐year‐olds (Study 1, n = 15, n = 12 respectively) and in a sample of 2‐year‐olds with both fNIRS data collected at age 2 and language outcome data at age 3 (Study 2, n = 18). In Study 1, 2‐ and 3‐year‐olds differentiated between communicative and noncommunicative stimuli as well as between speech and gestures in the left lateral frontal region. However, 2‐year‐olds showed different patterns of activation from 3‐year‐olds in right medial frontal regions. In Study 2, which included two toddlers identified with early language delays along with 16 typically developing toddlers, neural differentiation of communicative stimuli in the right medial frontal region at age 2 predicted receptive language at age 3. Specifically, after accounting for variance related to verbal ability at age 2, increased neural activation for communicative gestures (vs. both communicative speech and noncommunicative gestures) at age 2 predicted higher receptive language scores at age 3. These results are discussed in the context of the underlying mechanisms of toddler language development and use of fNIRS in prediction of language outcomes.

Preverbal Communication Complexity in Infants

The development of prelinguistic communication in typically developing infants is marked by changes in complexity as well as frequency, yet most measures focus on frequency. In the current study we used the Communication Complexity Scale (CCS) to measure prelinguistic complexity of typically developing infants in a cross-sectional sample of 6-, 8-, 10- and 12-month-olds (N = 204) during semi-structured play interaction. For each toy/interactive episode, infants' highest level of communication complexity (ranging from 0 for no response to 12 for multi-word verbalization), for both joint attention (i.e., social) and behavior regulation (e.g., requesting) functions, was scored. In addition, the same interaction was coded for frequency of all prelinguistic communication acts. Results of multivariate models indicated age-related differences in prelinguistic complexity. Measures of prelinguistic complexity and frequency evidenced moderate to strong correlations, with age-related differences by function (joint attention and behavior regulation). Significant associations with parent-report communication questionnaires were observed for both complexity and frequency measures. Results indicate that evaluating complexity of infant preverbal communication skill with the CCS is a valuable approach that can meaningfully index developmental differences in prelinguistic and early linguistic communication.

Communicative Use of Triadic Eye Gaze in Children With Down Syndrome, Autism Spectrum Disorder, and Other Intellectual and Developmental Disabilities

Purpose This study examines differences in the communicative use of triadic eye gaze (TEG) during a communicative interaction in 2 neurodevelopmental disorders: Down syndrome (DS) and autism spectrum disorders (ASD), and a 3rd group of varying disabilities associated with intellectual and developmental disabilities (IDDs). Also, the relationship between TEG use and language abilities was explored. Method Participants were 45 children, 15 in each group. The frequency of TEG was coded during a scripted communication assessment when children were between 3 and 6 years of age (37-73 months). Receptive and expressive language was measured using raw scores from the Mullen Scales of Early Learning concurrently between 3 and 6 years and again 2 years later when children were between 5 and 8 years (59-92 months). Results Descriptively, children with DS had a higher frequency of TEG than children with ASD and IDD, but significant differences were only observed between children with DS and ASD. More TEG at Time 1 in children with DS was associated with higher receptive language at Time 1 and higher expressive language at Time 2. For children with ASD, a trend for a positive association between TEG at Time 1 and language abilities at Time 2 was observed. No significant associations were observed for children with IDD. Conclusion Children with DS used TEG significantly more than children with ASD in this sample. Identifying strengths and weaknesses in TEG use is important because providing caregiver training to facilitate TEG can result in increased opportunities to respond with language models and promote language development.

Low Rates of Pointing in 18-Month-Olds at Risk for Autism Spectrum Disorder and Extremely Preterm Infants: A Common Index of Language Delay?

Infants with an older sibling with an Autism Spectrum Disorder diagnosis (Sibs ASD) are at high risk for language delay (LD) as well as infants born preterm, especially those with an extremely low gestational age (ELGA, GA ≤ 28 weeks). Gestures play a crucial role in language development and delays in gesture production may have negative cascading effects on it. The present exploratory study examined gesture production in 18-month-old infants with different underlying risks for LD. Seventy monolingual United States infants (41 Sibs ASD with no eventual ASD diagnosis and 29 infants with a typically developing older sibling -Sibs TD) and 40 monolingual Italian infants (20 ELGA without major cerebral damages, congenital malformations or sensory impairments and 20 full-term - FT infants, GA ≥ 37 weeks) were included. Both groups were followed longitudinally from 18 to 24, 30, and 36 months (corrected for ELGA infants). A 30-minute mother-infant play session with age-appropriate toys was video recorded at 18 months of age. Deictic (requesting, pointing, showing and giving), conventional, and representational gestures spontaneously produced by infants were coded; rate per 10 min was calculated. LD was defined as a score ≤10th percentile on the American English or Italian version of the MacArthur-Bates CDI on at least two time points between 18 and 36 months. Fifteen Sibs ASD and 9 ELGA infants were identified as infants with LD. Sibs ASD-LD and Sibs ASD-no LD produced fewer pointing gestures compared to Sibs TD (p = 0.038; p = 0.004); ELGA-LD infants produced significantly fewer pointing gestures than ELGA-no LD (p = 0.024) and FT (p = 0.006) infants. Low rates of pointing at 18 months are a marker of LD in Sibs ASD and ELGA infants. The potential implications of reduced pointing production and characteristics of different populations at risk for LD should be considered for understanding the emergence of LD.

Complex Sociality of Wild Chimpanzees Can Emerge from Laterality of Manual Gestures

Humans are strongly lateralized for manual gestures at both individual and population levels. In contrast, the laterality bias in primates is less strong, leading some to suggest that lateralization evolved after the Pan and Homo lineages diverged. However, laterality in humans is also context-dependent, suggesting that observed differences in lateralization between primates and humans may be related to external factors such as the complexity of the social environment. Here we address this question in wild chimpanzees and examine the extent to which the laterality of manual gestures is associated with social complexity. Right-handed gestures were more strongly associated with goal-directed communication such as repair through elaboration in response to communication failure than left-handed gestures. Right-handed gestures occurred in evolutionarily urgent contexts such as in interactions with central individuals in the network, including grooming reciprocity and mating, whereas left-handed gestures occurred in less-urgent contexts, such as travel and play. Right-handed gestures occurred in smaller parties and in the absence of social competition relative to left-handed gestures. Right-handed gestures increased the rate of activities indicating high physiological arousal in the recipient, whereas left-handed gestures reduced it. This shows that right- and left-handed gestures differ in cognitive and social complexity, with right-handed gestures facilitating more complex interactions in simpler social settings, whereas left-handed gestures facilitate more rewarding interactions in complex social settings. Differences in laterality between other primates and humans are likely to be driven by differences in the complexity of both the cognitive skills underpinning social interactions and the social environment.

New insights from children with early focal brain injury: Lessons to be learned from examining STEM-related skills

The study of cognitive development in children with early brain injury reveals crucial information about the developing brain and its plasticity. However, information on long-term outcomes of these children, especially in domains relevant to science, technology, engineering, and math (STEM) remains limited. In the current review, our goal is to address the existing research on cognitive development of children with pre- or perinatal focal brain lesion (PL) as it relates to children's STEM-related skills and suggest future work that could shed further light on the developmental trajectories of children with PL. We argue that examining STEM-related development in children with PL will have broader implications for our understanding of the nature of the plasticity children with PL exhibit as well as address theoretical questions in the field regarding the foundation skills for STEM, including visuospatial and mathematical skills.

Parents Influence the Visual Learning Environment Through Children's Manual Actions

The present research studied children in the second year of life (N = 29, M_age  = 21.14 months, SD = 2.64 months) using experimental manipulations within and between subjects to show that responsive parental influence helps children have more frequent sustained object holds with fewer switches between objects compared to when parents are either not involved or over-involved. Regardless of parental involvement, sustained holds were visually rich, based on the size, centeredness, and dominance of the held object relative to other objects. These findings are important because they suggest not only that the child's body creates visually rich scenes across play contexts but also that a responsive parent can increase the frequency of these visually rich and informative moments.

What Our Hands Tell Us: A Two-Year Follow-Up Investigating Outcomes in Subgroups of Children With Language Delay

Purpose This study followed up children identified with expressive language delay (ELD) or receptive/expressive language delay (R/ELD) at 2 years of age, Time 1 (T1), in order to identify their language profiles at 4-5 years, Time 2 (T2), and explore relationships to T1 language, gesture use, and symbolic comprehension. Method Nineteen of 22 children were seen at follow-up (9 of 10 from R/ELD group, 10 of 12 from ELD group). T1 measures assessed receptive and expressive language, gesture use, and symbolic comprehension. At T2, we assessed receptive and expressive language, sentence repetition, and expressive phonology. Results Outcomes for the R/ELD group were significantly poorer, with all children continuing to have delay in receptive and/or expressive language compared to just 20% of the ELD group. Expressive phonology delay was common in both groups. T1 receptive language showed the most pervasive correlations with T2 language measures, but categorical performance on all three T1 measures correctly predicted language outcomes in 16-17 of the 19 children. Conclusion Findings add to evidence that receptive language is a strong predictor of outcomes. Gesture use and symbolic comprehension are also strong predictors and clinically valuable as part of play-based assessments with implications for theoretical understanding and intervention planning.

Associations Between Manual Dexterity and Language Ability in School-Age Children

Purpose

We aimed to determine whether individual differences in manual dexterity are associated with specific language skills (nonword repetition, receptive vocabulary, and receptive grammar) after controlling for nonverbal abilities (visual–spatial working memory and intelligence).

Method

We assessed manual dexterity using the pegboard task and examined relationships with verbal and nonverbal abilities in a diverse community sample of children ( N = 63, mean age = 8;2 [year;months], range: 6;0–10;8) varying in language ability (Comprehensive Evaluation of Language Fundamentals–Fourth Edition core language score M = 105, range: 62–126; Semel, Wiig, & Secord, 2003).

Results

Correlational analyses indicated significant relationships between manual dexterity and performance on tests of nonword repetition, receptive vocabulary, receptive grammar, and nonverbal intelligence, after controlling for multiple comparisons. In regression analyses, manual dexterity remained a significant predictor of nonword repetition after controlling for nonverbal abilities and age. In contrast, manual dexterity was no longer significant in predicting receptive vocabulary or grammar when nonverbal intelligence was included as a factor in the model.

Conclusions

These findings build on prior work implicating poor fine motor control in child language disorders by identifying a robust relationship between manual dexterity and nonword repetition. Relationships between manual dexterity and receptive language abilities appear to be indirect and mediated by nonword repetition. For clinicians, the results underscore the importance of screening children with poor fine motor control for concomitant language impairments.