Quantifying latent social motivation and its associations with joint attention and language in infants at high and low likelihood for autism spectrum disorder

Social motivation—the psychobiological predisposition for social orienting, seeking social contact, and maintaining social interaction—manifests in early infancy and is hypothesized to be foundational for social communication development in typical and atypical populations. However, the lack of infant social-motivation measures has hindered delineation of associations between infant social motivation, other early-arising social abilities such as joint attention, and language outcomes. To investigate how infant social motivation contributes to joint attention and language, this study utilizes a mixed longitudinal sample of 741 infants at high (HL = 515) and low (LL = 226) likelihood for ASD. Using moderated nonlinear factor analysis (MNLFA), we incorporated items from parent-report measures to establish a novel latent factor model of infant social motivation that exhibits measurement invariance by age, sex, and familial ASD likelihood. We then examined developmental associations between 6- and 12-month social motivation, joint attention at 12–15 months, and language at 24 months of age. On average, greater social-motivation growth from 6–12 months was associated with greater initiating joint attention (IJA) and trend-level increases in sophistication of responding to joint attention (RJA). IJA and RJA were both positively associated with 24-month language abilities. There were no additional associations between social motivation and future language in our path model. These findings substantiate a novel, theoretically driven approach to modeling social motivation and suggest a developmental cascade through which social motivation impacts other foundational skills. These findings have implications for the timing and nature of intervention targets to support social communication development in infancy.

Highlights

• We describe a novel, theoretically based model of infant social motivation wherein multiple parent-reported indicators contribute to a unitary latent social-motivation factor.
• Analyses revealed social-motivation factor scores exhibited measurement invariance for a longitudinal sample of infants at high and low familial ASD likelihood.
• Social-motivation growth from ages 6–12 months is associated with better 12−15-month joint attention abilities, which in turn are associated with greater 24-month language skills.
• Findings inform timing and targets of potential interventions to support healthy social communication in the first year of life.

     

Splenium development and early spoken language in human infants

The association between developmental trajectories of language‐related white matter fiber pathways from 6 to 24 months of age and individual differences in language production at 24 months of age was investigated. The splenium of the corpus callosum, a fiber pathway projecting through the posterior hub of the default mode network to occipital visual areas, was examined as well as pathways implicated in language function in the mature brain, including the arcuate fasciculi, uncinate fasciculi, and inferior longitudinal fasciculi. The hypothesis that the development of neural circuitry supporting domain‐general orienting skills would relate to later language performance was tested in a large sample of typically developing infants. The present study included 77 infants with diffusion weighted MRI scans at 6, 12 and 24 months and language assessment at 24 months. The rate of change in splenium development varied significantly as a function of language production, such that children with greater change in fractional anisotropy (FA) from 6 to 24 months produced more words at 24 months. Contrary to findings from older children and adults, significant associations between language production and FA in the arcuate, uncinate, or left inferior longitudinal fasciculi were not observed. The current study highlights the importance of tracing brain development trajectories from infancy to fully elucidate emerging brain–behavior associations while also emphasizing the role of the splenium as a key node in the structural network that supports the acquisition of spoken language.     

Adaptation of the Mullen Scales of Early Learning for use among infants aged 5‐ to 24‐months in rural Gambia

Infants in low‐resource settings are at heightened risk for compromised cognitive development due to a multitude of environmental insults in their surroundings. However, the onset of adverse outcomes and trajectory of cognitive development in these settings is not well understood. The aims of the present study were to adapt the Mullen Scales of Early Learning (MSEL) for use with infants in a rural area of The Gambia, to examine cognitive development in the first 24‐months of life and to assess the association between cognitive performance and physical growth. In Phase 1 of this study, the adapted MSEL was tested on 52 infants aged 9‐ to 24‐months (some of whom were tested longitudinally at two time points). Further optimization and training were undertaken and Phase 2 of the study was conducted, where the original measures were administered to 119 newly recruited infants aged 5‐ to 24‐months. Infant length, weight and head circumference were measured concurrently in both phases. Participants from both phases were split into age categories of 5–9 m (N = 32), 10–14 m (N = 92), 15–19 m (N = 53) and 20–24 m (N = 43) and performance was compared across age groups. From the ages of 10–14 m, Gambian infants obtained lower MSEL scores than US norms. Performance decreased with age and was lowest in the 20–24 m old group. Differential onsets of reduced performance were observed in the individual MSEL domains, with declines in visual perception and motor performance detected as early as at 10–14 months, while reduced language scores became evident after 15–19 months of age. Performance on the MSEL was significantly associated with measures of growth.     

Early communicative gestures and play as predictors of language development in children born with and without family risk for dyslexia

The present study investigated early communicative gestures, play, and language skills in children born with family risk for dyslexia (FR) and a control group of children without this inheritable risk at ages 12, 15, 18, and 24 months. Participants were drawn from the Tromsø Longitudinal study of Dyslexia (TLD) which follows children's cognitive and language development from age 12 months through Grade 2 in order to identify early markers of developmental dyslexia. Results showed that symbolic play and parent reported play at age 12 months and communicative gestures at age 15 months explained 61% of the variance in productive language at 24 months in the FR group. These early nonlinguistic measures seem to be potentially interesting markers of later language development in children born at risk for dyslexia.     

Testing joint attention, imitation, and play as infancy precursors to language and theory of mind

Various theoretical accounts propose that an important developmental relation exists between joint attention, play, and imitation abilities, and later theory of mind ability. However, very little direct empirical evidence supports these claims for putative “precursor” theory of mind status. A small sample (N=13) of infants, for whom measures of play, joint attention, and imitation had been collected at 20 months of age, was followed-up longitudinally at 44 months and a battery of theory of mind measures was conducted. Language and IQ were measured at both timepoints. Imitation ability at 20 months was longitudinally associated with expressive, but not receptive, language ability at 44 months. In contrast, only the joint attention behaviours of gaze switches between an adult and an active toy and looking to an adult during an ambiguous goal detection task at 20 months were longitudinally associated with theory of mind ability at 44 months. It is argued that joint attention, play, and imitation, and language and theory of mind, might form part of a shared social–communicative representational system in infancy that becomes increasingly specialised and differentiated as development progresses.     

Infant responding to joint attention, executive processes, and self-regulation in preschool children

Infant joint attention is related to behavioral and social outcomes, as well as language in childhood. Recent research and theory suggests that the relations between joint attention and social-behavioral outcomes may reflect the role of executive self-regulatory processes in the development of joint attention. To test this hypothesis two studies were conducted. The first, cross-sectional study examined the development of responding to joint attention (RJA) skill in terms of increasing executive efficiency of responding between 9 and 18 months of age. The results indicated that development of RJA was characterized by a decreased latency to shift attention in following another person's gaze and head turn, as well as an increase in the proportion of correct RJA responses exhibited by older infants. The second study examined the longitudinal relations between 12-month measures of responding to joint attention and 36-month attention regulation in a delay of gratification task. The results indicated that responding to joint attention at 12-months was significantly related to children's use of three types of self-regulation behaviors while waiting for a snack reward at 36 months of age. These observations are discussed in light of a developmental theory of attention regulation and joint attention in infancy.     

SES differences in language processing skill and vocabulary are evident at 18 months

This research revealed both similarities and striking differences in early language proficiency among infants from a broad range of advantaged and disadvantaged families. English‐learning infants (n = 48) were followed longitudinally from 18 to 24 months, using real‐time measures of spoken language processing. The first goal was to track developmental changes in processing efficiency in relation to vocabulary learning in this diverse sample. The second goal was to examine differences in these crucial aspects of early language development in relation to family socioeconomic status (SES). The most important findings were that significant disparities in vocabulary and language processing efficiency were already evident at 18 months between infants from higher‐ and lower‐SES families, and by 24 months there was a 6‐month gap between SES groups in processing skills critical to language development.     

Development of infant sustained attention and its relation to EEG oscillations: an EEG and cortical source analysis study

The current study examined the relation between infant sustained attention and infant EEG oscillations. Fifty‐nine infants were tested at 6 (N = 15), 8 (N = 17), 10 (N = 14), and 12 (N = 13) months. Three attention phases, stimulus orienting, sustained attention, and attention termination, were defined based on infants' heart rate changes. Frequency analysis using simultaneously recorded EEG focused on infant theta (2–6 Hz), alpha (6–9 Hz), and beta (9–14 Hz) rhythms. Cortical source analysis of EEG oscillations was conducted with realistic infant MRI models. Theta synchronization was found over fontal pole, temporal, and parietal electrodes during infant sustained attention for 10 and 12 months. Alpha desynchronization was found over frontal, central and parietal electrodes during sustained attention. This alpha effect started to emerge at 10 months and became well established by 12 months. No difference was found for the beta rhythm between different attention phases. The theta synchronization effect was localized to the orbital frontal, temporal pole, and ventral temporal areas. The alpha desynchronization effect was localized to the brain regions composing the default mode network including the posterior cingulate cortex and precuneus, medial prefrontal cortex, and inferior parietal gyrus. The alpha desynchronization effect was also localized to the pre‐ and post‐central gyri. The present study demonstrates a connection between infant sustained attention and EEG oscillatory activities.     

The developmental pathways leading to pattern recognition, joint attention, language and cognition

According to the functional/emotional hypothesis, the core capacities necessary for cognitive and language development, such as pattern recognition, joint attention, and intention reading, are downstream effects of more basic processes having to do with early patterns of affect signalling. In this paper, we present preliminary research that tests the functional/emotional hypothesis. The data set consists of profiles of the emotional functioning of infants and young children at ages 0-3, 4-5, 6-9, 10-14, 15-18, 19-24, 25-30, and 31-42 months. Data were collected on a representative population of 1640 children across the US. Results of this preliminary research point to expected correlations between the development of affective signalling and pattern recognition, joint attention, and intention reading. However, we acknowledge that this is only the first step in providing supportive evidence for the functional/emotional hypothesis. Further research is needed to establish causal connections between affective signalling and the core capacities necessary for cognitive and language development.     

Fine motor skill predicts expressive language in infant siblings of children with autism

We investigated whether fine motor and expressive language skills are related in the later‐born siblings of children with autism (heightened‐risk, HR infants) who are at increased risk for language delays. We observed 34 HR infants longitudinally from 12 to 36 months. We used parent report and standardized observation measures to assess fine motor skill from 12 to 24 months in HR infants (Study 1) and its relation to later expressive vocabulary at 36 months in HR infants (Study 2). In Study 1, we also included 25 infants without a family history of autism to serve as a normative comparison group for a parent‐report fine motor measure. We found that HR infants exhibited fine motor delays between 12 and 24 months and expressive vocabulary delays at 36 months. Further, fine motor skill significantly predicted expressive language at 36 months. Fine motor and expressive language skills are related early in development in HR infants, who, as a group, exhibit risk for delays in both. Our findings highlight the importance of considering fine motor skill in children at risk for language impairments and may have implications for early identification of expressive language difficulties.     

Oscillatory gamma activity mediates the pathway from socioeconomic status to language acquisition in infancy

BackgroundThe predictable path to child language acquisition is largely constrained by both brain maturation and environmental experience. The synchronized activity of large numbers of neurons gives rise to macroscopic brain oscillations on an electroencephalogram (EEG). It has been found that neural oscillations at rest in the gamma frequency band (25–45 Hz) are associated with development of different cognitive systems, including language. Although the etiology of language is explained by genetically driven brain maturation factors, environment plays a significant role. Specifically, candidate pathways from environment to language development include sociodemographic factors, primarily socioeconomic status (SES) which is likely to exert its effects on language development through other factors, such as parenting style.Despite these assumptions, no studies have so far examined the interrelation between brain maturation factors such as gamma frequency oscillatory activity, environmental factors such as SES, and language acquisition.Aim and methodIn a longitudinal study of 84 Italian typically developing infants, we measured the power of oscillatory gamma activity as mediator between SES and language acquisition. Baseline EEG and information about SES were collected when infants were aged 6 months. Children were followed-up longitudinally to measure expressive vocabulary and Mean Length of Utterance (MLU) at 24 months.ResultsThe mediation model showed that SES is associated with gamma power which, in turn, is associated with expressive language at age 24 months. A higher SES predicted an increase in left central gamma power which, in turn, predicted better language scores.ConclusionsThese results confirm the predictive role of gamma activity oscillatory activity on later language acquisition, suggesting a specific role for these oscillatory mechanisms in language development milestones such as vocabulary development and early word combination. Furthermore, they suggest that SES differences in brain activity may be apparent at early stages of life and affect later language skills. If replicated, our findings could contribute to identifying highest-risk children and may prompt cost-effective preventive/treatment strategies.     

Infant sustained attention but not joint attention to objects at 9 months predicts vocabulary at 12 and 15 months

Vocabulary differences early in development are highly predictive of later language learning as well as achievement in school. Early word learning emerges in the context of tightly coupled social interactions between the early learner and a mature partner. In the present study, we develop and apply a novel paradigm—dual head‐mounted eye tracking—to record momentary gaze data from both parents and infants during free‐flowing toy‐play contexts. With fine‐grained sequential patterns extracted from continuous gaze streams, we objectively measure both joint attention and sustained attention as parents and 9‐month‐old infants played with objects and as parents named objects during play. We show that both joint attention and infant sustained attention predicted vocabulary sizes at 12 and 15 months, but infant sustained attention in the context of joint attention, not joint attention itself, is the stronger unique predictor of later vocabulary size. Joint attention may predict word learning because joint attention supports infant attention to the named object.     

The mediating role of joint attention in the relationship between motor skills and receptive and expressive language in siblings at risk for autism spectrum disorder

Language problems are highly prevalent in younger siblings of children with autism spectrum disorder (HR-sibs), yet little is known about early predictors. There is growing evidence that motor and language development are linked and this connection might be mediated by joint attention. Developmental changes in motor abilities change how children interact with objects and people (e.g., by showing), which may influence language development. This association has however not yet been studied in HR-sibs. The interrelationship between motor, joint attention and language skills was explored in younger siblings of typically developing children (LR-sibs, N = 31) and HR-sibs (N = 32). In both groups, motor skills (composite of fine and gross motor skills) at 10 months influenced receptive and expressive language at 36 months directly and indirectly through joint attention at 14 months. Group status moderated this direct and indirect effect with mainly significant effects in HR-sibs. This indicates that lower motor skills can have cascading effects on joint attention and language in HR-sibs. Consequently, assessment of early motor skills in HR-sibs might hold promise for early identification of motor difficulties but can also be indicative of language difficulties later in life, especially when difficulties with joint attention are also present.     

Frontolimbic neural circuitry at 6 months predicts individual differences in joint attention at 9 months

Elucidating the neural basis of joint attention in infancy promises to yield important insights into the development of language and social cognition, and directly informs developmental models of autism. We describe a new method for evaluating responding to joint attention performance in infancy that highlights the 9‐ to 10‐month period as a time interval of maximal individual differences. We then demonstrate that fractional anisotropy in the right uncinate fasciculus, a white matter fiber bundle connecting the amygdala to the ventral‐medial prefrontal cortex and anterior temporal pole, measured in 6‐month‐olds predicts individual differences in responding to joint attention at 9 months of age. The white matter microstructure of the right uncinate was not related to receptive language ability at 9 months. These findings suggest that the development of core nonverbal social communication skills in infancy is largely supported by preceding developments within right lateralized frontotemporal brain systems.     

Infant recall memory and communication predicts later cognitive development

This longitudinal study investigates the relation between recall memory and communication in infancy and later cognitive development. Twenty-six typically developing Swedish children were tested during infancy for deferred imitation (memory), joint attention (JA), and requesting (nonverbal communication); they also were tested during childhood for language and cognitive competence. Results showed that infants with low performance on both deferred imitation at 9 months and joint attention at 14 months obtained a significantly lower score on a test of cognitive abilities at 4 years of age. This long-term prediction from preverbal infancy to childhood cognition is of interest both to developmental theory and to practice.     

SOCIOEMOTIONAL AND BEHAVIORAL PROBLEMS IN TODDLERS WITH LANGUAGE DELAY

Toddlers with language delay are at risk for persistent developmental and behavioral difficulties; however, the association between socioemotional/behavior problems and language in young children is not well understood. This study explored socioemotional/behavior problems in a unique sample of toddlers with language delays using a measure developed explicitly for this age group. Toddlers identified by 18 months with receptive and expressive language delay (LD; n = 30) or typical development (TD; n = 61) were evaluated at 18 and 24 months of age using the Infant‐Toddler Social and Emotional Assessment (ITSEA) and the Mullen Scales of Early Learning. Compared to toddlers who had TD, toddlers with LD had significantly more concerning scores at 18 and 24 months on all ITSEA domains. The rate of “clinical concern” on most domains was not high in either group, except that >60% of LD toddlers were in the clinical concern range on the Competence domain. Socioemotional/behavioral problems were dimensionally related to receptive and expressive language, with greater language delay associated with more concerning ITSEA scores. Socioemotional and behavioral problems are related to receptive and expressive language abilities in 18‐ and 24‐month‐olds, indicating the need for screening of both types of concerns in toddlers identified with potential language delays.     

Higher attention bias for fear at 8 months of age is associated with better socioemotional competencies during toddlerhood

BackgroundIn previous studies, an attention bias for signals of fear and threat has been related to socioemotional problems, such as anxiety symptoms, and socioemotional competencies, such as altruistic behaviors in children, adolescents and adults. However, previous studies lack evidence about these relations among infants and toddlers.AimsOur aim was to study the association between the individual variance in attention bias for faces and, specifically, fearful faces during infancy and socioemotional problems and competencies during toddlerhood.Study design and subjectsThe study sample was comprised of 245 children (112 girls). We explored attentional face and fear biases at the age of 8 months using eye tracking and the face-distractor paradigm with neutral, happy and fearful faces and a scrambled-face control stimulus. Socioemotional problems and competencies were reported by parents with the Brief Infant and Toddler Social Emotional Assessment (BITSEA) when children were 24 months old.Outcome measures and resultsA higher attentional fear bias at 8 months of age was related to higher levels of socioemotional competence at 24 months of age (β = .18, p = .008), when infants’ sex and temperamental affectivity, maternal age, education and depressive symptoms were controlled. We found no significant association between attentional face or fear bias and socioemotional problems.ConclusionsWe found that the heightened attention bias for fearful faces was related to positive outcomes in early socioemotional development. Longitudinal study designs are needed to explore the changes in the relation between the attention bias for fear or threat and socioemotional development during early childhood.     

Infants' joint attention skills predict toddlers' emerging mental state language

To assess predictive relations between joint attention skills, intention understanding, and mental state vocabulary, 88 children were tested with measures of comprehension of gaze and referential pointing, as well as the production of declarative gestures and the comprehension and production of imperative gestures, at the ages of 7-18 months. Infants' intention-based imitation skills were assessed at 12, 15, and 18 months. At the ages of 24 and 36 months, toddlers' internal state lexicon was evaluated by parents with a German adaptation of the Mental State Language Questionnaire (Olineck & Poulin-Dubois, 2005). Regression analyses revealed that 9-months-olds' comprehension of referential pointing contributed significantly to the prediction of intention-based imitation skills at 15 months, as well as to children's volition and cognition vocabularies at 24 and 36 months, respectively. Moreover, 12-month-olds' comprehension of an imperative motive was shown to selectively predict toddlers' use of volition terms at 24 months. Overall, these results provide empirical evidence for both general and specific developmental relations between preverbal communication skills and mental state language, thus implying developmental continuity within the social domain in the first 3 years of life.     

Socio-cognitive influences on the domain-specificity of prosocial behavior in the second year

The main aim of this study was to explain the domain-specificity of early prosocial behavior in different domains (i.e., helping, comforting, and cooperation) by simultaneously assessing specific socio-cognitive factors (i.e., self-other-differentiation and joint attentional skills) that were hypothesized to be differentially related to the three domains of prosocial behavior. Based on a longitudinal study design, observational and parental report data were collected when toddlers (N = 42) from German urban middle-class families were 15 and 18 months of age. At 15 months, regression analyses indicated differential relationships between socio-cognitive development and prosocial behavior (i.e., joint attentional skills were positively related with helping and, as hypothesized, both joint attentional skills and self-other differentiation were positively related with cooperation). Furthermore, self-other differentiation at 15 months predicted increases in coordination between 15 and 18 months. Finally, between 15 and 18 months, parental reports of socio-cognitive measures increased significantly while behavioral measures of both socio-cognitive concepts and prosocial behavior were stable across time. In sum, these results support the theoretical assumption of domain-specific socio-cognitive influences that constitute differential development of prosocial behavior. Implications of the results for theory and future studies are discussed from different perspectives with a focus on an interference interpretation calling for the integration of socialization approaches to the study of prosocial development.     

Auditory joint attention skills: Development and diagnostic differences during infancy

To date, joint attention skill assessments have focused on children’s responses to multimodal bids (RJA) and their initiation of bids (IJA) to multimodal spectacles. Here we gain a systematic view of auditory joint attention skills using a novel assessment that measures both auditory and multimodal RJA and IJA. In Study 1, 47 typically developing (TD) children were tested 5 times from 12 to 30 months to document auditory joint attention skill development. In Study 2, 113 toddlers (39 TD, 33 autism spectrum disorder [ASD], and 41 non-ASD developmental disorders [DD]; average age 22.4 months) were tested to discern the effects of ASD. Our findings fit well within the established depiction of joint attention skills with one important caveat: auditory items were far more difficult to execute than multimodal ones. By 24 months, TD children passed multimodal RJA items at the near-ceiling level, an accomplishment not reached even by 30 months for auditory RJA items. Intentional communicative IJA bids also emerged more slowly to auditory spectacles than to multimodal spectacles. Toddlers with DD outperformed toddlers with ASD on multimodal RJA items but toddlers in both groups rarely passed any auditory RJA items. Toddlers with ASD often monitored their partner’s attention during IJA items, albeit less often than toddlers with DD and TD toddlers, but they essentially never produced higher-level IJA bids, regardless of modality. Future studies should investigate further how variations in bids and targets affect auditory joint attention skills and probe the relation between these skills and language development.