Child-directed action promotes 2-year-olds’ imitation

Infant-directed communication: Examining the many dimensions of everyday caregiver-infant interactions

Everyday caregiver-infant interactions are dynamic and multidimensional. However, existing research underestimates the dimensionality of infants' experiences, often focusing on one or two communicative signals (e.g., speech alone, or speech and gesture together). Here, we introduce "infant-directed communication" (IDC): the suite of communicative signals from caregivers to infants including speech, action, gesture, emotion, and touch. We recorded 10 min of at-home play between 44 caregivers and their 18- to 24-month-old infants from predominantly white, middle-class, English-speaking families in the United States. Interactions were coded for five dimensions of IDC as well as infants' gestures and vocalizations. Most caregivers used all five dimensions of IDC throughout the interaction, and these dimensions frequently overlapped. For example, over 60% of the speech that infants heard was accompanied by one or more non-verbal communicative cues. However, we saw marked variation across caregivers in their use of IDC, likely reflecting tailored communication to the behaviors and abilities of their infant. Moreover, caregivers systematically increased the dimensionality of IDC, using more overlapping cues in response to infant gestures and vocalizations, and more IDC with infants who had smaller vocabularies. Understanding how and when caregivers use all five signals-together and separately-in interactions with infants has the potential to redefine how developmental scientists conceive of infants' communicative environments, and enhance our understanding of the relations between caregiver input and early learning. RESEARCH HIGHLIGHTS: Infants' everyday interactions with caregivers are dynamic and multimodal, but existing research has underestimated the multidimensionality (i.e., the diversity of simultaneously occurring communicative cues) inherent in infant-directed communication. Over 60% of the speech that infants encounter during at-home, free play interactions overlap with one or more of a variety of non-speech communicative cues. The multidimensionality of caregivers' communicative cues increases in response to infants' gestures and vocalizations, providing new information about how infants' own behaviors shape their input. These findings emphasize the importance of understanding how caregivers use a diverse set of communicative behaviors-both separately and together-during everyday interactions with infants.

Object play and problem solving in infancy: Insights into tool use

Tool use is primarily, but not exclusively, present in species with otherwise advanced cognitive traits. However, the interaction between such traits and conspecific inter-individual variation in the presence, complexity, or intensity of tool use is far from being established. We addressed this matter among human infants, seeking factors that relate to differences in tool use. We examined, both correlationally and experimentally, whether the propensity to engage in object combinations predicts performance in means-end problem-solving tasks involving or not involving the use of a tool. We tested 71 infants aged 15, 18, 21, and 24 months, dividing them into two subgroups: one exposed to an adult demonstrating object-object combinations (i.e., "prompting" infants to combine objects together) and another with comparable social exposure but where the adult demonstrated single-object manipulations. We found a correlation between the combined level of spontaneous and prompted object combinations and problem-solving performance regardless of the involvement of tools in the problem. However, we did not find differences in tool-use performance between the two demonstration subgroups. The correlational analysis suggests that complexity of play, as measured by the frequency of combining objects, is linked to infants' problem-solving skills rather than being specifically associated with tool use, as previously suggested in the literature.

How infant-directed actions enhance infants' attention, learning, and exploration: Evidence from EEG and computational modeling

When teaching infants new actions, parents tend to modify their movements. Infants prefer these infant-directed actions (IDAs) over adult-directed actions and learn well from them. Yet, it remains unclear how parents' action modulations capture infants' attention. Typically, making movements larger than usual is thought to draw attention. Recent findings, however, suggest that parents might exploit movement variability to highlight actions. We hypothesized that variability in movement amplitude rather than higher amplitude is capturing infants' attention during IDAs. Using EEG, we measured 15-month-olds' brain activity while they were observing action demonstrations with normal, high, or variable amplitude movements. Infants' theta power (4-5 Hz) in fronto-central channels was compared between conditions. Frontal theta was significantly higher, indicating stronger attentional engagement, in the variable compared to the other conditions. Computational modelling showed that infants' frontal theta power was predicted best by how surprising each movement was. Thus, surprise induced by variability in movements rather than large movements alone engages infants' attention during IDAs. Infants with higher theta power for variable movements were more likely to perform actions successfully and to explore objects novel in the context of the given goal. This highlights the brain mechanisms by which IDAs enhance infants' attention, learning, and exploration.

The role of social signals in segmenting observed actions in 18-month-old children

Learning about actions requires children to identify the boundaries of an action and its units. Whereas some action units are easily identified, parents can support children's action learning by adjusting the presentation and using social signals. However, currently, little is understood regarding how children use these signals to learn actions. In the current study, we investigate the possibility that communicative signals are a particularly suitable cue for segmenting events. We investigated this hypothesis by presenting 18-month-old children (N = 60) with short action sequences consisting of toy animals either hopping or sliding across a board into a house, but interrupting this two-step sequence either (a) using an ostensive signal as a segmentation cue, (b) using a non-ostensive segmentation cue and (c) without additional segmentation information between the actions. Marking the boundary using communicative signals increased children's imitation of the less salient sliding action. Imitation of the hopping action remained unaffected. Crucially, marking the boundary of both actions using a non-communicative control condition did not increase imitation of either action. Communicative signals might be particularly suitable in segmenting non-salient actions that would otherwise be perceived as part of another action or as non-intentional. These results provide evidence of the importance of ostensive signals at event boundaries in scaffolding children's learning.

Everyday interactions support toddlers' learning of conventional actions on artifacts

Children learn to perform actions on artifacts in their environments from infancy, but the ways caregivers support this learning during everyday interactions are relatively unexplored. This study investigated how naturalistic caregiver-child teaching interactions promoted conventional action learning in toddlers. Caregivers of 32 24- to 26-month-old children taught their children to perform novel target actions on toys. Afterward, an experimenter blind to the toys children had been taught tested children's action learning. Results indicated that children's propensities to assemble objects and vocabularies were positively associated with learning. Whereas caregivers' speech did not directly support learning, caregivers' action performance negatively related to children's learning. Importantly, children's own actions related to learning: Children who performed proportionally more actions relative to their caregivers with higher action accuracy demonstrated better learning of the taught material. Thus, children who "drove" the teaching session and were more accurate in their actions learned more. Caregivers contributed by supporting their children's actions: Caregivers who provided more specific instructions and praise had children who were more active during instruction. Importantly, analyses controlled for child-level individual differences, showing that beyond children's own skills, active experience supported by caregiver guidance related to conventional action learning. These findings highlight children as central agents in the learning process and suggest that caregivers contributed by coaching children's actions.

Starting at Birth: An Integrative, State-of-the-Science Framework for Optimizing Infant Neuromotor Health

Numerous conditions and circumstances place infants at risk for poor neuromotor health, yet many are unable to receive treatment until a definitive diagnosis is made, sometimes several years later. In this integrative perspective, we describe an extensive team science effort to develop a transdiagnostic approach to neuromotor health interventions designed to leverage the heightened neuroplasticity of the first year of life. We undertook the following processes: (1) conducted a review of the literature to extract common principles and strategies underlying effective neuromotor health interventions; (2) hosted a series of expert scientific exchange panels to discuss common principles, as well as practical considerations and/or lessons learned from application in the field; and (3) gathered feedback and input from diverse stakeholders including infant caregivers and healthcare providers. The resultant framework was a pragmatic, evidence-based, transdiagnostic approach to optimize neuromotor health for high-risk infants based on four principles: (a) active learning, (b) environmental enrichment, (c) caregiver engagement, and (d) strength-based approaches. In this perspective paper, we delineate these principles and their potential applications. Innovations include: engagement of multiple caregivers as critical drivers of the intervention; promoting neuromotor health in the vulnerability phase, rather than waiting to treat neuromotor disease; integrating best practices from adjacent fields; and employing a strengths-based approach. This framework holds promise for implementation as it is scalable, pragmatic, and holistically addresses both the needs of the infant and their family.

Informing, Coordinating, and Performing: A Perspective on Functions of Sensorimotor Communication

Sensorimotor communication is a form of communication instantiated through body movements that are guided by both instrumental, goal-directed intentions and communicative, social intentions. Depending on the social interaction context, sensorimotor communication can serve different functions. This article aims to disentangle three of these functions: (a) an informing function of body movements, to highlight action intentions for an observer; (b) a coordinating function of body movements, to facilitate real-time action prediction in joint action; and (c) a performing function of body movements, to elicit emotional or aesthetic experiences in an audience. We provide examples of research addressing these different functions as well as some influencing factors, relating to individual differences, task characteristics, and situational demands. The article concludes by discussing the benefits of a closer dialog between separate lines of research on sensorimotor communication across different social contexts.

Motion tracking of parents' infant- versus adult-directed actions reveals general and action-specific modulations

Parents tend to modulate their movements when demonstrating actions to their infants. Thus far, these modulations have primarily been quantified by human raters and for entire interactions, thereby possibly overlooking the intricacy of such demonstrations. Using optical motion tracking, the precise modulations of parents' infant-directed actions were quantified and compared to adult-directed actions and between action types. Parents demonstrated four novel objects to their 14-month-old infants and adult confederates. Each object required a specific action to produce a unique effect (e.g. rattling). Parents were asked to demonstrate an object at least once before passing it to their demonstration partner, and they were subsequently free to exchange the object as often as desired. Infants' success at producing the objects' action-effects was coded during the demonstration session and their memory of the action-effects was tested after a several-minute delay. Indicating general modulations across actions, parents repeated demonstrations more often, performed the actions in closer proximity and demonstrated action-effects for longer when interacting with their infant compared to the adults. Meanwhile, modulations of movement size and velocity were specific to certain action-effect pairs. Furthermore, a 'just right' modulation of proximity was detected, since infants' learning, memory, and parents' prior evaluations of their infants' motor abilities, were related to demonstrations that were performed neither too far from nor too close to the infants. Together, these findings indicate that infant-directed action modulations are not solely overall exaggerations but are dependent upon the characteristics of the to-be learned actions, their effects, and the infant learners.

Teacher-learner interaction quantifies scaffolding behaviour in imitation learning

Teachers often believe that they take into account learners’ ongoing learning progress in their teaching. Can behavioural data support this belief? To address this question, we investigated the interactive behavioural coordination between teachers and learners during imitation learning to solve a puzzle. The teacher manually demonstrated the puzzle solution to a learner who immediately imitated and learned it. Manual movements of teachers and learners were analysed using a bivariate autoregressive model. To identify bidirectional information exchange and information shared between the two agents, we calculated causality and noise covariance from the model. Information transfer observed from teacher to learner in the lateral component of their motion indicated imitation of the spatial information of the puzzle solution. Information transfer from learner to teacher in the vertical component of their motion indicated the monitoring process through which teachers adjust their timing of demonstration to the learner’s progress. The shared information in the lateral component increased as learning progressed, indicating the knowledge was shared between the two agents. Our findings demonstrated that the teacher interactively engaged in and contingently supported (i.e. scaffolded) imitation. We thus provide a behavioural signature of the teacher’s intention to promote learning indispensable for understanding the nature of teaching.

Effects of a brain tumor in a dispersive human head on SAR and temperature rise distributions due to RF sources at 4G and 5G frequencies

In this paper, effects of a brain tumor located in a dispersive human head model on specific absorption rate (SAR) and temperature rise distributions due to different types of RF sources at 4G and 5G cellular frequencies are investigated with the use of a multiphysics model. This multiphysics model analyzes the dispersive human head with the brain tumor and provides the SAR and temperature rise distributions in the head due to the RF source operated at 4G and 5G cellular frequencies in a single finite-difference time-domain simulation. An adjacent antenna operated at 4G and 5G cellular frequencies to the human head is considered as the RF source for near-field exposure, while a plane wave field radiated by base stations operated at 4G and 5G cellular frequencies is considered as the RF source for far-field exposure. Numerical results show that the brain tumor in the head slightly affects the SAR and temperature rise distributions due to different RF sources at 4G and 5G cellular frequencies.

Subtle temporal delays of mothers' responses affect imitation learning in children: Mother-child interaction study

The relationship between temporal contiguity of mothers' teaching behaviors and children's imitation learning was investigated. Participants (2-year-old children) observed their mothers' demonstration of using novel toys over a double television system under live and delayed conditions. The dyads normally interacted in the live condition, whereas they interacted with a 1-s time delay inserted between the children's actions and mothers' responses in the delayed condition. Then, the children were tested with identical toys. Results indicated that children's smiling responses and imitation performances were significantly decreased in the delayed condition compared with the live condition, although mothers' teaching approach did not differ between conditions. These results suggest that a subtle temporal delay in mothers' responses could affect young children's imitation learning.

Communicative intent modulates production and comprehension of actions and gestures: A Kinect study

Actions may be used to directly act on the world around us, or as a means of communication. Effective communication requires the addressee to recognize the act as being communicative. Humans are sensitive to ostensive communicative cues, such as direct eye gaze (Csibra & Gergely, 2009). However, there may be additional cues present in the action or gesture itself. Here we investigate features that characterize the initiation of a communicative interaction in both production and comprehension. We asked 40 participants to perform 31 pairs of object-directed actions and representational gestures in more- or less- communicative contexts. Data were collected using motion capture technology for kinematics and video recording for eye-gaze. With these data, we focused on two issues. First, if and how actions and gestures are systematically modulated when performed in a communicative context. Second, if observers exploit such kinematic information to classify an act as communicative. Our study showed that during production the communicative context modulates space-time dimensions of kinematics and elicits an increase in addressee-directed eye-gaze. Naïve participants detected communicative intent in actions and gestures preferentially using eye-gaze information, only utilizing kinematic information when eye-gaze was unavailable. Our study highlights the general communicative modulation of action and gesture kinematics during production but also shows that addressees only exploit this modulation to recognize communicative intention in the absence of eye-gaze. We discuss these findings in terms of distinctive but potentially overlapping functions of addressee directed eye-gaze and kinematic modulations within the wider context of human communication and learning.

Verbal labels increase the salience of novel objects for preschoolers with typical development and Williams syndrome, but not in autism

BACKGROUND

Early research has documented that young children show an increased interest toward objects that are verbally labeled by an adult, compared to objects that are presented without a label. It is unclear whether the same phenomenon occurs in neurodevelopmental disorders affecting social development, such as autism spectrum disorder (ASD) and Williams syndrome (WS).

METHODS

The present study used a novel eye-tracking paradigm to determine whether hearing a verbal label increases the salience of novel objects in 35 preschoolers with ASD, 18 preschoolers with WS, and 20 typically developing peers.

RESULTS

We found that typically developing children and those with WS, but not those with ASD, spent significantly more time looking at objects that are verbally labeled by an adult, compared to objects that are presented without a label.

CONCLUSIONS

In children without ASD, information accompanied by the speaker's verbal label is accorded a "special status," and it is more likely to be attended to. In contrast, children with ASD do not appear to attribute a special salience to labeled objects compared to non-labeled objects. This result is consistent with the notion that reduced responsivity to pedagogical cues hinders social learning in young children with ASD.

Clarifying the range of social-cognitive processes subserving human teaching

An evolutionary framework on human teaching is not well equipped to explain the nature of human teaching unless it specifies the subserving cognitive and motivational mechanisms. Only a theory that speculates on the psychological processes provides testable predictions and stimulates further empirical research.

Infant's action skill dynamically modulates parental action demonstration in the dyadic interaction

When interacting with infants, human adults modify their behaviours in an exaggerated manner. Previous studies have demonstrated that infant-directed modification affects the infant's behaviour. However, little is known about how infant-directed modification is elicited during infant-parent interaction. We investigated whether and how the infant's behaviour affects the mother's action during an interaction. We recorded three-dimensional information of cup movements while mothers demonstrated a cup-nesting task during interaction with their infants aged 11 to 13 months. Analyses revealed that spatial characteristics of the mother's task demonstration clearly changed depending on the infant's object manipulation. In particular, the variance in the distance that the cup was moved decreased after the infant's cup nesting and increased after the infant's task-irrelevant manipulation (e.g. cup banging). This pattern was not observed for mothers with 6- to 8-month-olds, who do not have the fine motor skill to perform the action. These results indicate that the infant's action skill dynamically affects the infant-directed action and suggest that the mother is sensitive to the infant's potential to learn a novel action. A video abstract of this article can be viewed at: https://www.youtube.com/watch?v=VNS2IHwLIhg&feature=youtu.be.

Imitation (rather than core language) predicts pragmatic development in young children with ASD: a preliminary longitudinal study using CDI parental reports

BACKGROUND

Research in the last decades has clearly pointed to the important role of language and communicative level when trying to understand developmental trajectories in children with autism spectrum disorders (ASD).

AIMS

The purpose of this longitudinal study was to investigate whether (1) core language skills, measured as expressive vocabulary and grammar, and/or (2) pre-linguistic social-communicative skills, including gestures and imitation abilities, drive pragmatic language development in young children with ASD.

METHODS & PROCEDURES

We examined correlates and longitudinal predictors of pragmatic growth in a sample of 34 children with Autism spectrum disorder (ASD), whose parents were given parts of two MacArthur Communicative Developmental Inventories (CDI: Words & Gestures and CDI: Words & Sentences) for completion at two time points (at time 1 the mean child age was 41 months, and at time 2 it was 54 months). A novel feature in this study is that the relevant parts from both CDI forms were included at both time points, allowing us to examine whether pre-linguistic social-communication skills (e.g. imitation and gesturing) and/or core language skills (i.e. grammar and vocabulary) predict pragmatic language growth.

OUTCOMES & RESULTS

The results show that basically all pre-linguistic, linguistic and pragmatic skills were associated concurrently. When controlling for possible confounders and for the autoregressive effect, imitation skills predicted pragmatic growth over time, whereas core language did not. This could only have been shown by the use of both CDI forms.

CONCLUSIONS & IMPLICATIONS

This preliminary study may be of both conceptual and methodological importance for research in the field of language and communication development in ASD. Imitation may play a pivotal role in the development of subsequent conversational pragmatic abilities in young children with ASD. Future research should be directed at unravelling the mechanisms underlying this association.