The context of infants' giving gestures in mother-infant dyads: Typical giving gestures and those contingent on exploration and play

This study aimed to focus on a niche that has not yet been investigated in infants' gesture studies that is the effect of the prior context of one specific gestural behavior (gives) on maternal behavior. For this purpose, we recruited 23 infants at 11 and 13 months of age yielded 246 giving gesture bouts that were performed in three contexts: typical when the object was offered immediately, contingent on exploration, and contingent on play. The analysis revealed that maternal responses to infants' giving gestures varied and were affected by their age and gesture context. Hence, mothers amended their responses according to the background that generated each gesture. The number of verbal responses to infants' giving gestures decreased as the infants aged, whereas the number of pretense responses increased. For infants aged 11 months, mothers generally provided motor responses to typical gestures. However, for infants aged 13 months, this trend declined and was replaced by a strong positive correlation between giving gestures contingent on play and verbal responses. We concluded that the type of activity with objects prior to employing giving gestures could enhance infants' symbolic skills because caregivers monitor the contingent act that yields the gesture that shapes their response.     

Becoming a Communicative Partner: Infant Contingent Responsiveness to Maternal Language and Gestures

Infant contingent responsiveness to maternal language and gestures was examined in 190 Mexican American, Dominican American, and African American infant–mother dyads when infants were 14 and 24 months. Dyads were video‐recorded during book‐sharing and play. Videos were coded for the timing of infants’ vocalizations and gestures and mothers’ referential language (i.e., statements that inform infants about objects and events in the world; e.g., “That's a big doggy!”), regulatory language (i.e., statements that regulate infants’ attention or actions; e.g., “Look at that”, “Put it down!”), and gestures. Infants of all three ethnicities responded within 3 sec of mothers’ language and gestures, increased their responsiveness over development, and displayed specificity in their responses: They vocalized and gestured following mothers’ referential language and gestures, but were less likely than chance to communicate following mothers’ regulatory language. At an individual level, responsive infants had responsive mothers.     

What's in a Name When It Isn't a Word? 17‐Month‐Olds' Mapping of Nonverbal Symbols to Object Categories

Infants begin acquiring object labels as early as 12 months of age. Recent research has indicated that the ability to acquire object names extends beyond verbal labels to other symbolic forms, such as gestures. This experiment examines the latitude of infants' early naming abilities. We tested 17‐month‐olds' ability to map gestures, nonverbal sounds, and pictograms to object categories using a forced‐choice triad task. Results indicated that infants accept a wide range of symbolic forms as object names when they are embedded in familiar referential naming routines. These data suggest that infants may initially have no priority for words over other symbolic forms as object names, although the relative status of words appears to change with development. The implications of these findings for the development of criteria for determining whether a symbol constitutes an object name early in development are considered.     

Mothers' Verbal and Nonverbal Strategies in Relation to Infants' Object‐Directed Actions in Real Time and Across the First Three Years in Ethnically Diverse Families

We examined maternal behavioral strategies in relation to infants' object‐directed actions in real time and over developmental time in 206 mother–infant dyads from African American, Dominican immigrant, and Mexican immigrant backgrounds. Mothers were asked to share a set of beads and strings with their infants when children were 14, 24, and 36 months. We coded three types of maternal strategies—eliciting attention, instructive assistance, and encouragement—which could be expressed verbally (e.g., “look”, “turn it”, “good job!”) or physically (i.e., through gestures, hands‐on guidance, or transfer of objects). We also coded infants' unassisted bead‐stringing. Across ethnic groups and ages, mothers' hands‐on guidance and object transfer increased the likelihood that infants would follow with unassisted bead‐stringing during real‐time interaction. Over developmental time, mothers modified their strategies: They displayed fewer attention‐getting strategies and more encouragement across infant ages, and peaked in their provision of instructive assistance when infants were 24 months. Additionally, Mexican mothers displayed more nonverbal strategies (e.g., gestures, hands‐on guidance) than did African American and/or Dominican mothers, who displayed more verbal strategies (e.g., attention‐getting and encouraging language). Developmental and real‐time patterns in mother–infant object‐related interactions generalize across ethnicities, although mothers' emphases on specific strategies are culture specific.     

Verbal Labels and Gestural Routines in Parental Communication with Young Children

Infants initially use words and symbolic gestures in markedly similar ways, to name and refer to objects. The goal of these studies is to examine how parental verbal and gestural input shapes infants' expectations about the communicative functions of words and gestures. The studies reported here suggest that infants may initially accept both words and gestures as symbols because parents often produce both verbal labels and gestural routines within the same joint-attention contexts. In two studies, we examined the production of verbal and gestural labels in parental input during joint-attention episodes. In Study 1, parent-infant dyads engaged in a picture-book reading task in which parents introduced their infants to drawings of unfamiliar objects (e.g., accordion). Parents' verbal labeling far outstripped their gestural communication, but the number of gestures produced was non-trivial and was highly predictive of infant gestural production. In Study 2, parent-infant dyads engaged in a free-play session with familiar objects. In this context, parents produced both verbal and gestural symbolic acts frequently with reference to objects. Overall, these studies support an input-driven explanation for why infants acquire both words and gestures as object names, early in development.     

5‐Month‐Olds’ Categorization of Novel Objects: Task and Measure Dependence

To examine key parameters of the initial conditions in early category learning, two studies compared 5‐month‐olds’ object categorization between tasks involving previously unseen novel objects, and between measures within tasks. Infants in Experiment 1 participated in a visual familiarization–novelty preference (VFNP) task with two‐dimensional (2D) stimulus images. Infants provided no evidence of categorization by either their looking or their examining even though infants in previous research systematically categorized the same objects by examining when they could handle them directly. Infants in Experiment 2 participated in a VFNP task with 3D stimulus objects that allowed visual examination of objects’ 3D instantiation while denying manual contact with the objects. Under these conditions, infants demonstrated categorization by examining but not by looking. Focused examination appears to be a key component of young infants’ ability to form category representations of novel objects, and 3D instantiation appears to better engage such examining.     

Impact of Symbolic Gesturing on Early Language Development

The purpose of the present study was to evaluate the effect on verbal language development of purposefully encouraging hearing infants to use simple gestures as symbols for objects, requests, and conditions. To this end, 103, 11-month-old infants were divided into three groups, all of whom were seen in the laboratory for a variety of assessments, including standardized language tests at 15, 19, 24, 30, and 36 months. Parents of those in the Sign Training group modeled symbolic gestures and encouraged their infants to use them. Parents of infants in the Non-intervention Control group knew nothing about symbolic gestures or our special interest in language development. As a control for training effects (i.e., effects attributable to families being engaged in a language intervention program), parents of a second control group of infants (the Verbal Training group) were asked to make special efforts to model verbal labels. After comparisons of the two control groups minimized concerns about training effects, comparisons between the Sign Training and the Non-intervention Control group indicated an advantage for the Sign Training group on the vast majority of language acquisition measures. These results provide strong evidence that symbolic gesturing does not hamper verbal development and may even facilitate it. A variety of possible explanations for such an effect are discussed.     

Preference for Dynamic Human Images and Gaze‐Following Abilities in Preterm Infants at 6 and 12 Months of Age: An Eye‐Tracking Study

Preterm children are reported to be at higher risk of social communication problems such as autism spectrum disorder compared with full‐term infants. Although previous studies have suggested that preference for social stimuli in infancy is a possible indicator of later social communication development, little is known about this relation in preterm infants. We examined the gaze behavior of low‐risk preterm and full‐term infants at 6 and 12 months' corrected ages using two types of eye‐tracking tasks, which measured 1) preference for social stimuli by biological motion and human geometric preference and 2) ability to follow another's gaze direction. We found that preterm (compared with full‐term) infants at both 6 and 12 months of age spent less time looking toward dynamic human images, followed another's gaze less frequently, and looked for a shorter time at an object cued by another. Moreover, we found a positive correlation between looking time toward dynamic human images and frequency of gaze following at 12 months of age in full‐term, but not preterm, infants. We discuss the relation between the atypical patterns of gaze behavior in preterm infants and their higher risk of later social communication problems.     

Infants' Evolving Representations of Object Motion During Occlusion: A Longitudinal Study of 6‐ to 12‐Month‐Old Infants

Infants' ability to track temporarily occluded objects that moved on circular trajectories was investigated in 20 infants using a longitudinal design. They were first seen at 6 months and then every 2nd month until the end of their 1st year. Infants were presented with occlusion events covering 20% of the target's trajectory (effective occlusion interval ranged from 500–4,000 msec). Gaze was measured using an ASL 504 infrared eye‐tracking system. Results effectively demonstrate that infants from 6 months of age can represent the spatiotemporal dynamics of occluded objects. Infants at all ages tested were able to predict, under certain conditions, when and where the object would reappear after occlusion. They moved gaze accurately to the position where the object was going to reappear and scaled their timing to the current occlusion duration. The average rate of predictive gaze crossings increased with occlusion duration. These results are discussed as a 2‐factor process. Successful predictions are dependent on strong representations, themselves dependent on the richness of information available during encoding and graded representations.     

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.     

Disappearing Décalage: Object Search in Light and Dark at 6 Months

Infants search for an object hidden by an occluder in the light months later than one hidden by darkness. One explanation attributes this décalage to easier action demands in darkness versus occlusion, whereas another attributes it to easier representation demands in darkness versus occlusion. However, search tasks typically confound these two types of demands. This article presents a search task that unconfounds them to better address these two explanations of the “dark advantage.” Objects were hidden by submersion in liquid instead of occlusion with a screen, allowing infants to search with equally simple actions in light versus dark. In Experiment 1, 6‐month‐olds unexpectedly showed a dark disadvantage by discriminating when an object was hidden in the light but not the dark. Experiment 2 addressed the possibility that representation demands were higher in the dark than the light and showed that infants’ search in the dark increased to match that in the light, but not exceed it. Six‐month‐olds can thus search for a hidden object both when action demands are simplified and when a noncohesive substance rather than a cohesive occluder hides the object, supporting aspects of both action‐demand and representation‐demand explanations of décalage in search behavior.     

Longitudinal assessment of social attention in preterm and term infants: Its relation to social communication and language outcome

Preterm birth has been reported to be associated with an increased risk of social communication and language problems. Recently, we found that preterm infants showed atypical patterns of social attention compared with term infants. However, it is still unknown how social attention develops and whether the individual differences are associated with developmental outcomes for social communication and language in preterm infants. The social attention of preterm and term infants at 6, 12, and 18 months was investigated using two types of social attention tasks (human-geometric preference task and gaze-following task). The Modified Checklist for Autism in Toddlers (M-CHAT) and the MacArthur Communicative Development Inventory adapted for Japanese were measured at 18 months. We found that compared with term infants, preterm infants spent less time looking toward dynamic human images and followed another's gaze directions less frequently through 6, 12, and 18 months. Moreover, hierarchical multiple regression analysis revealed that less preference for dynamic human images and gaze-following abilities was associated with high M-CHAT and low language scores in preterm and term infants, respectively. These findings suggest that birth status affects development of social attention through 18 months and individual differences in social attention reflect differences in social communication and language outcomes.     

How What We See and What We Know Influence Iconic Gesture Production

In face-to-face communication, speakers typically integrate information acquired through different sources, including what they see and what they know, into their communicative messages. In this study, we asked how these different input sources influence the frequency and type of iconic gestures produced by speakers during a communication task, under two degrees of task complexity. Specifically, we investigated whether speakers gestured differently when they had to describe an object presented to them as an image or as a written word (input modality) and, additionally, when they were allowed to explicitly name the object or not (task complexity). Our results show that speakers produced more gestures when they attended to a picture. Further, speakers more often gesturally depicted shape information when attended to an image, and they demonstrated the function of an object more often when they attended to a word. However, when we increased the complexity of the task by forbidding speakers to name the target objects, these patterns disappeared, suggesting that speakers may have strategically adapted their use of iconic strategies to better meet the task’s goals. Our study also revealed (independent) effects of object manipulability on the type of gestures produced by speakers and, in general, it highlighted a predominance of molding and handling gestures. These gestures may reflect stronger motoric and haptic simulations, lending support to activation-based gesture production accounts.     

The Development of Anticipatory Smiling

When do infants begin to communicate positive affect about physical objects to their social partners? We examined developmental changes in the timing of smiles during episodes of initiating joint attention that involved an infant gazing between an object and a social partner. Twenty‐six typically developing infants were observed at 8, 10, and 12 months during the Early Social‐Communication Scales, a semistructured assessment for eliciting initiating joint attention and related behaviors. The proportion of infant smiling during initiating joint attention episodes did not change with age, but there was a change in the timing of the smiles. The likelihood of infants smiling at an object and then gazing at the experimenter while smiling (anticipatory smiling) increased between 8 and 10 months and remained stable between 10 and 12 months. The increase in the number of infants who smiled at an object and then made eye contact suggests a developing ability to communicate positive affect about an object.     

A parent gesture intervention as a means to increase parent declarative pointing and child vocabulary

This study examined whether a brief parent gesture training resulted in a change in the communicative intent of pointing gestures used by parents of infants from age 10–12 months and whether specific types of points (declarative vs. imperative) were more or less likely to predict later child language skill at 18 months. Compared to parents who were randomized to the control group, parents in the intervention group produced significantly more declarative pointing gestures as a result of the intervention. Moreover, parents’ use of declarative points at 12 months was predictive of later child vocabulary comprehension at 18 months. These findings suggest that a short-term parent training can have important effects on the communicative intentions conveyed through gesture which predict vocabulary development.     

Quantity and Quality of Gestural Input: Caregivers’ Sensitivity Predicts Caregiver–Infant Bidirectional Communication Through Gestures

Children's use of pointing and symbolic gestures—early communication skills which predict later language—is influenced by frequency of adults’ gestures. However, we wonder whether, like language, the sensitivity of adult–child interactions is also important for encouraging child gesturing, rather than simply quantity of adult gestural input. Furthermore, children's use of gestures influences qualities of adult–child interaction, eliciting greater responsiveness and richer communication. Thus, we investigated the moderating role of nonparental caregiver sensitivity on the relationship between caregivers’ and infants’ use of pointing and symbolic gestures. We observed 10 infants (ages 6–19 months) over 8 months with a total of 24 student caregivers completing short‐term internships, recording adult and child use of pointing and symbolic gestures. We used longitudinal growth models to examine change in gesturing and moderating roles of caregiver sensitivity in the relations between caregiver and child gesturing behavior. Caregivers’ sensitivity moderated effects of caregivers’ symbolic gestures on infants’ pointing and symbolic gestures, and the effects of infants’ pointing and symbolic gesture frequency on caregivers’ gesture use. Thus, caregivers’ gestures are most effective in supporting child gestures when in the context of sensitive interactions. Sensitivity is central to supporting children's early communicative behaviors, including pointing and symbolic gestures.     

Young Infants' Perception of Object Unity in Rotation Displays

Much research has been devoted to questions regarding how infants begin to perceive the unity of partly occluded objects, and it is clear that object motion plays a central role. Little is known, however, about how infants' motion processing skills are used in such tasks. One important kinetic cue for object shape is structure from motion, but its role in unity perception remains unknown. To address this issue, we presented 2‐ and 4‐month‐old infants with displays in which object unity was specified by vertical rotation. After habituation to this display, infants viewed broken and complete versions of the object to test their preference for the broken object, an indication of perception of unity in the occlusion display. Positive evidence for the perception of unity was provided by both age groups. Concomitant edge translation available in 1 condition did not appear to contribute above and beyond simple rotation. These results suggest that structure from motion, and perhaps contour deformation and shading cues, can contribute important information for veridical object percepts in very young infants.     

Pointing as Epistemic Request: 12‐month‐olds Point to Receive New Information

Infants start pointing systematically to objects or events around their first birthday. It has been proposed that infants point to an event to share their appreciation of it with others. In this study, we tested another hypothesis, according to which infants’ pointing could also serve as an epistemic request directed to the adult. Thus, infants’ motivation for pointing could include the expectation that adults would provide new information about the referent. In two experiments, an adult reacted to 12‐month‐olds’ pointing gestures by exhibiting “Informing” or “Sharing” behavior. In response, infants pointed more frequently across trials in the Informing than in the Sharing condition. This suggests that the feedback that contained new information matched infants’ expectations more than mere attention sharing. Such a result is consistent with the idea that not just the comprehension but also the production of early communicative signals is tuned to assist infants’ learning from others.