"Go, go, go!" Mothers' verbs align with infants' locomotion.

Caregivers often tailor their language to infants' ongoing actions (e.g., "are you stacking the blocks?"). When infants develop new motor skills, do caregivers show concomitant changes in their language input? We tested whether the use of verbs that refer to locomotor actions (e.g., "come," "bring," "walk") differed for mothers of 13-month-old crawling (N = 16) and walking infants (N = 16), and mothers of 18-month-old experienced walkers (N = 16). Mothers directed twice as many locomotor verbs to walkers compared to same-age crawlers, but mothers' locomotor verbs were similar for younger and older walkers. In real-time, mothers' use of locomotor verbs was dense when infants were locomoting, and sparse when infants were stationary, regardless of infants' crawler/walker status. Consequently, infants who spent more time in motion received more locomotor verbs compared to infants who moved less frequently. Findings indicate that infants' motor skills guide their in-the-moment behaviors, which in turn shape the language they receive from caregivers. RESEARCH HIGHLIGHTS: Infants' motor skills guide their in-the-moment behaviors, which in turn shape the language they receive from caregivers. Mothers directed more frequent and diverse verbs that referenced locomotion (e.g., "come," "go," "bring") to walking infants compared to same-aged crawling infants. Mothers' locomotor verbs were temporally dense when infants locomoted and sparse when infants were stationary, regardless of whether infants could walk or only crawl.

Early development in autism: How developmental cascades help us understand the emergence of developmental differences.

Many theories of autism spectrum disorder (ASD) focus on a single system or factor as an explanatory mechanism for autism symptoms and behavior. However, there is growing recognition that ASD is a complex, multisystem neurodevelopmental condition with origins in prenatal life. Researchers therefore need a conceptual framework that allows examination of the interplay between multiple interacting domains and systems and the ways in which they extend their influence beyond the individual into the surrounding environment. The developmental cascades perspective suggests that even relatively small perturbations in early emerging behaviors in domains that are not traditionally linked may influence subsequent achievements across these areas. In this chapter, we illustrate how a developmental cascades framework can be used to inform the study of developmental differences. The developmental cascades perspective provides us with conceptual and methodological tools for considering how variation in children's real time behavior can provide new insights into sources of variation in their developmental trajectories and outcomes. It also suggests approaches for intervention that leverage targeted skills in novel ways, creating opportunities to support development in other domains and fine-tune caregiver behavior to create powerful moments for infant learning.

Infant locomotion shapes proximity to adults during everyday play in the U.S.

Learning to walk expands infants' access to the physical environment and prompts changes in their communicative behaviors. However, little is known about whether walking also shapes infants' proximity to their adult social partners during everyday activities at home. Here we followed 89 infants (42 boys, 47 girls; 92% White, not Hispanic or Latino) longitudinally and documented connections between infant locomotion and infant-adult proximity on two timescales: (1) across developmental time, by comparing data from a session when infants could only crawl to a later session when they could walk (M walk onset = 12.15 months, range = 8-15); and (2) in real time, by testing whether the amount of time that infants spent in motion (regardless of their locomotor status) related to their interpersonal distance to adults. The developmental transition to walking corresponded to a significant, but modest, decrease in infant-adult proximity. Infants' moment-to-moment locomotion, however, was strongly related to patterns of interpersonal distance: infants who spent more time in motion spent less time near adults and instigated more proximity transitions, resulting in shorter and more dispersed bouts of proximity throughout sessions. Findings shed new light on how infants' motor achievements can reverberate across other domains of development, and how changes in infant development that researchers often observe over months arise from infants' moment-to-moment experiences.

Autism: The face value of eye contact.

Inattention to faces in clinical assessments is a robust marker for autism. However, a new study distinguishes diagnostic marker from behavioral mechanism, showing that face looking in everyday activity is equally rare in autistic and neurotypical children and not required for joint attention in either group.

Mothers talk about infants' actions: How verbs correspond to infants' real-time behavior.

Infants learn nouns during object-naming events-moments when caregivers name the object of infants' play (e.g., ball as infant holds a ball). Do caregivers also label the actions of infants' play (e.g., roll as infant rolls a ball)? We investigated connections between mothers' verb inputs and infants' actions. We video-recorded 32 infant-mother dyads for 2 hr at home (13 month olds, n = 16; 18 month olds, n = 16; girls, n = 16; White, n = 23; Asian, n = 2; Black, n = 1; other, n = 1; multiple races, n = 5; Hispanic/Latinx, n = 2). Dyads were predominantly from middle-class to upper middle-class households. We identified each manual verb (e.g., press, shake) and whole-body verb (e.g., kick, go) that mothers directed to infants. We coded whether infants displayed manual and/or whole-body actions during a 6-s window surrounding the verb (i.e., 3 s prior and 3 s after the named verb). Mothers' verbs and infant actions were largely congruent: Whole-body verbs co-occurred with whole-body actions, and manual verbs co-occurred with manual actions. Moreover, half of mothers' verbs corresponded precisely to infants' concurrent action (e.g., infant pressed button as mother said, "Press the button"). In most instances, mothers commented on rather than instigated infants' actions. Findings suggest that verb learning is embodied, such that infants' motor actions offer powerful cues to verb meanings. Furthermore, our approach highlights the value of cross-domain research integrating infants' developing motor and language skills to understand word learning. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

From description to generalization, or there and back again.

In his target article, Yarkoni prescribes descriptive research as a potential antidote for the generalizability crisis. In our commentary, we offer four guiding principles for conducting descriptive research that is generalizable and enduring: (1) prioritize context over control; (2) let naturalistic observations contextualize structured tasks; (3) operationalize the target phenomena rigorously and transparently; and (4) attend to individual data.

Communication changes when infants begin to walk.

Learning to walk allows infants to travel faster and farther and explore more of their environments. In turn, walking may have a cascading effect on infants' communication and subsequent responses from caregivers. We tested for an inflection point-a dramatic shift in the developmental progression-in infant communication and caregiver responses when infants started walking. We followed 25 infants longitudinally over 7 months surrounding the onset of walking (mean walk onset age = 11.76 months, SD = 1.56). After learning to walk, the pace of gesture growth (but not vocalization growth) increased substantially, and infants increasingly coordinated gestures and vocalizations with locomotion (e.g., by walking to a caregiver and showing off a toy bear). Consequently, caregivers had more opportunities to respond contingently to their infants during walking months compared to crawling months (e.g., "What did you find? Is that your bear?"). Changes in communication were amplified for infants who began walking at older ages, compared to younger walkers. Findings suggest that learning to walk marks a point in development when infants actively communicate in new ways, and consequently elicit rich verbal input from caregivers.

Object exploration during the transition to sitting: A study of infants at heightened risk for autism spectrum disorder.

Learning to sit promotes infants' object exploration because it offers increased access to objects and an improved position for exploration (e.g., ). Infants at heightened risk (HR) for autism spectrum disorder (ASD) exhibit delays in sitting and differences in object exploration. However, little is known about the association between sitting and object exploration among HR infants. We examined changes in object exploration as HR infants (N = 19) and comparison infants with no family history of ASD (Low Risk; LR; N = 23) gained experience sitting independently. Infants were observed monthly from 2.5 months until 1 month after the onset of independent sitting. At 12, 18, 24, and 36 months, infants completed standardized developmental assessments, and HR infants were assessed for ASD symptoms at 36 months. Although HR infants began sitting later than LR infants, both groups increased time spent grasping, shaking, banging, and mouthing objects as they gained sitting experience. Groups only differed in time spent actively mouthing objects, with LR infants showing a greater increase in active mouthing than HR infants. Findings suggest that HR infants experience a similar progression of object exploration across sitting development, but on a delayed time scale.

Profiles of Early Actions and Gestures in Infants With an Older Sibling With Autism Spectrum Disorder.

Purpose Infants with autism spectrum disorder (ASD) produce fewer play actions and gestures than neurotypical infants (e.g., Mastrogiuseppe et al., 2015; Veness et al., 2012; Zwaigenbaum et al., 2005). The purpose of this study was to investigate whether different "types" of actions and gestures are more or less likely to develop atypically in ASD. Method We examined eight types of actions and gestures longitudinally from ages 8 to 14 months in 80 infants with a heightened risk for developing ASD by virtue of having an affected older sibling (high risk [HR]; e.g., Ozonoff et al., 2011) and 25 infants with no such familial risk (low risk). Data were collected using the MacArthur-Bates Communicative Development Inventories (Fenson et al., 1994, 1993). Results HR infants later diagnosed with ASD showed less growth across nearly all types of actions and gestures compared to the low-risk comparison group. Importantly, these HR infants who were later diagnosed with ASD also exhibited reduced growth in frequent deictic gestures and in actions that involve object manipulation relative to HR infants with non-ASD language delay. Conclusions During infancy, it is challenging for clinicians to distinguish ASD from other early communicative delays (e.g., Camarata, 2014). Our results indicate that deictic gestures, as well as actions and gestures involving object manipulation, may be useful targets of surveillance strategies for HR infants and could support early detection efforts for ASD.

Infant Motor Development in Autism Spectrum Disorder: A Synthesis and Meta-analysis.

Studies of infant motor development in autism spectrum disorder (ASD) have increased in recent years. This article synthesized this literature through meta-analysis to assess (a) whether infant motor ability differs in ASD relative to neurotypical controls; and (b) whether motor ability and communication are related in infants with ASD. Study 1 aggregated data from 1,953 infants with ASD (ages 3.0-42.0 months), and Study 2 included 890 infants with ASD (age 6.0-42.9 months). Study 1 revealed that infant motor ability differed significantly in ASD compared with neurotypical infants-this difference was robust to variation in measurement and design. Furthermore, this group difference amplified as age increased. Study 2 indicated that within ASD, infant motor ability and communication are related.

The Relation Between Walking and Language in Infant Siblings of Children With Autism Spectrum Disorder.

In typical development, walk onset is accompanied by increased language growth (e.g., Walle & Campos, 2014). The present study explored whether this relation may be disrupted in the infant siblings of children with autism spectrum disorder (ASD; heightened risk of receiving an ASD diagnosis; HR), a population exhibiting substantial variability in motor and language development (e.g., Gamliel, Yirmiya, & Sigman, 2007; Landa & Garrett-Mayer, 2006). Receptive and expressive language were examined across the transition to walking in three groups of HR infants (no diagnosis, language delay, and ASD; N = 91, 8-18 months) and in infants with no family history of ASD (N = 25; 9-15 months). Only infants with an eventual ASD diagnosis did not show increased language growth following walk onset.

Word comprehension mediates the link between gesture and word production: Examining language development in infant siblings of children with autism spectrum disorder.

Children's gesture production precedes and predicts language development, but the pathways linking these domains are unclear. It is possible that gesture production assists in children's developing word comprehension, which in turn supports expressive vocabulary acquisition. The present study examines this mediation pathway in a population with variability in early communicative abilities-the younger siblings of children with autism spectrum disorder (ASD; high-risk infants, HR). Participants included 92 HR infants and 28 infants at low risk (LR) for ASD. A primary caregiver completed the MacArthur-Bates Communicative Development Inventory (Fenson, et al., 1993) at 12, 14, and 18 months, and HR infants received a diagnostic evaluation for ASD at 36 months. Word comprehension at 14 months mediated the relationship between 12-month gesture and 18-month word production in LR and HR infants (ab = 0.263; p < 0.01). For LR infants and HR infants with no diagnosis or language delay, gesture was strongly associated with word comprehension (as = 0.666; 0.646; 0.561; ps < 0.01). However, this relationship did not hold for infants later diagnosed with ASD (a = 0.073; p = 0.840). This finding adds to a growing literature suggesting that children with ASD learn language differently. Furthermore, this study provides an initial step toward testing the developmental pathways by which infants transition from early actions and gestures to expressive language.

Coordination is key: Joint attention and vocalisation in infant siblings of children with Autism Spectrum Disorder.

BACKGROUND: Research indicates that social communicative behaviours develop atypically during the second year in Autism Spectrum Disorder (ASD). This study evaluated whether these behaviours also differed in the extent to which they were coordinated across modalities. AIMS: To measure joint attention behaviours (e.g., gaze shifts, gestures), vocalisations and their coordination among a cohort of infants with an older sibling with ASD (heightened risk-HR). METHODS & PROCEDURES: This prospective longitudinal study examined 50 HR infants at 14, 18 and 24 months. The Early Social Communication Scales (ESCS)-a structured toy-play task that assesses infant joint attention behaviour-was administered to infants at each age point in the home. Infants' joint attention behaviours, vocalisations and instances where they overlapped were coded from videos. At 36 months, nine infants received an ASD diagnosis (HR-ASD), 15 had a significant language delay (HR-LD) and 26 were classified no diagnosis (HR-ND). OUTCOMES & RESULTS: Findings revealed that HR-ASD infants produced fewer advanced joint attention behaviours, and their vocalisations were less frequent and less advanced than HR-LD and HR-ND infants. Notably, HR-ASD infants also coordinated these behaviours together less frequently than their HR peers. CONCLUSIONS & IMPLICATIONS: Differences in the coordination of early communicative behaviours may have negative cascading effects on social and language development for infants who develop ASD. Current intervention practices may be complemented by efforts to increase the coordinated quality of communicative behaviours.

Early Gesture and Vocabulary Development in Infant Siblings of Children with Autism Spectrum Disorder.

This study examined longitudinal growth in gestures and words in infants at heightened (HR) versus low risk (LR) for ASD. The MacArthur-Bates Communicative Development Inventory was administered monthly from 8 to 14 months and at 18 and 24 months to caregivers of 14 HR infants diagnosed with ASD (HR-ASD), 27 HR infants with language delay (HR-LD), 51 HR infants with no diagnosis (HR-ND), and 28 LR infants. Few differences were obtained between LR and HR-ND infants, but HR-LD and HR-ASD groups differed in initial skill levels and growth patterns. While HR-LD infants grew at rates comparable to LR and HR-ND infants, growth was attenuated in the HR-ASD group, with trajectories progressively diverging from all other groups.

The development of autism spectrum disorders: variability and causal complexity.

The autism spectrum is highly variable, both behaviorally and neurodevelopmentally. Broadly speaking, four related factors contribute to this variability: (1) genetic processes, (2) environmental events, (3) gene × environment interactions, and (4) developmental factors. Given the complexity of the relevant processes, it appears unlikely that autism spectrum atypicalities can be attributed to any one causal mechanism. Rather, the development of neural atypicality reflects an interaction of genetic and environmental risk factors. As the individual grows, changes in neural atypicality, consequent variation in behavior, and environmental response to that behavior may become linked in a positive feedback loop that amplifies deviations from the typical developmental pattern. WIREs Cogn Sci 2017, 8:e1426. doi: 10.1002/wcs.1426 For further resources related to this article, please visit the WIREs website.