Development of Infant Pointing from 10 to 12 months: The Role of Relevant Caregiver Responsiveness

Infants’ pointing frequency is a predictor of their later language abilities. Yet, predictors of pointing frequency in the first year of life are not well understood. Study 1 explored what factors in infants and caregivers at 10 months would predict the pointing frequency of infants at 12 months (N = 35). Infant‐driven predictors were infants’ fine‐motor skills and point‐following abilities. Caregiver‐mediated predictors were caregivers’ pointing frequency and responsiveness toward infants’ pointing. Relevant caregiver responsiveness at 10 months predicted infants’ pointing frequency at 12 months, controlling for the other factors and infants’ prior pointing frequency. Study 2 explored whether child‐level factors influence caregivers’ responsiveness (N = 49). We examined the hand shape of infants’ pointing (whole‐hand versus index‐finger) and the presence of point‐accompanying vocalizations. Infants’ vocalization‐accompanied points were more likely to elicit relevant responses from caregivers, while hand shapes played a less pronounced role. Together, the findings reveal an early emerging mutual relationship between infant pointing and caregiver behavior such that certain characteristics of infant pointing predict caregivers’ responsiveness, and relevant responsiveness toward infants’ pointing predicts the increase in infants’ pointing frequencies.     

What's the point? Infants' and adults' perception of different pointing gestures

Adults and infants as young as 4 months old orient to pointing gestures. Although adults are shown to orient faster to index-finger pointing than other hand shapes, it is unknown whether hand shapes influence infants' perception of pointing. In this study, we used a spatial cueing paradigm on an eye tracker to investigate whether and to what extent adults and 12-month-old infants orient their attention in the direction of pointing gestures with different hand shapes: index finger, whole hand, and pinky finger. Furthermore, we assessed infants' and their parents' pointing production. Results revealed that adults showed a reliable cueing effect: shorter saccadic reaction times (SRTs) to congruent than incongruent targets, for all hand shapes. However, they did not show a larger cueing effect triggered by the index or any other finger. This contradicts previous findings and is discussed with respect to the differences in methodology. Infants showed a cueing effect only for the whole hand but not for the index or pinky fingers. The current results suggest that infants' orienting to pointing may be more robust for the whole hand shape in the first year, and tuning in to the social-communicative relevance of the canonical index finger shape may develop later or require additional social-communicative cues.     

Relation of infants' and mothers' pointing to infants' vocabulary measured directly and with parental reports

Infants' and parents' pointing gestures predict infants' concurrent and prospective language development. Most studies have measured vocabulary size using parental reports. However, parents tend to underestimate or overestimate infants' vocabulary necessitating the use of direct measures alongside parent reports. The present study examined whether mothers' index-finger pointing, and infants' whole-hand and index-finger pointing at 14 months associate with infants' receptive and expressive vocabulary based on parental reports and directly measured lexical processing efficiency (LPE) concurrently at 14 months and prospectively at 18 months. We used the decorated room paradigm to measure pointing frequency, the Turkish communicative development inventory I to measure infants' receptive vocabulary, Turkish communicative development inventory II to measure their expressive vocabulary, and the Looking-While-Listening (LWL) task to measure LPE. At 14 months, 34 mother-infant dyads, and at 18 months, 30 dyads were included in the analyses. We found that only infants' index-finger pointing frequency at 14 months predicted their LPE (both reaction time and accuracy) prospectively at 18 months but not concurrently at 14 months. Neither maternal pointing nor infants' pointing predicted their receptive and expressive vocabulary based on indirect measurement. The results extend the evidence on the relation between index-finger pointing and language development to a more direct measure of vocabulary.     

The Pointing–Vocal Coupling Progression in the First Half of the Second Year of Life

This study investigated the development of the pointing–vocal coupling system. We were interested in the infants’ behavior to attune prosody with pointing intentions. Twenty‐five children were involved at 12, 15, and 18 months of age in an experimental procedure devised to elicit imperative and declarative pointing. Pointing, vocality associated with pointing, and the prosody of that vocality were analyzed. A significant increase in the coupling of pointing and vocality was observed from 12 to 15 months, and in the ability to differentiate prosody with respect to the intention of the gesture from 15 to 18 months. Also, the infants who pointed declaratively at 12 months were likely to couple declarative pointing with vocality at 15 months, and the infants who coupled at 15 months were likely to differentiate prosody by the pointing intention at 18 months. Results suggest that the match between prosody and pointing intentions emerges gradually during the first half of the second year of life. They also show a relationship between earlier and later pointing–vocal coupling, and a role for declarative communication in promoting that progression. Overall, our study supports the view of intentional communication as a time‐based and context‐based developmental process.     

Correlates of infant pointing frequency in the first year

This study examines the emergence of concurrent correlates of infant pointing frequency with the aim of contributing to its ontogenetic theories. We measured monthly from 8 to 12 months infants' (N = 56) index-finger pointing frequency along with several candidate correlates: (1) family socioeconomic status (SES), (2) mothers' pointing production, and (3) infants' point following to targets in front of and behind them. Results revealed that (1) infants increased their pointing frequency across age, but high-SES infants had a steeper increase, and a higher pointing frequency than low-SES infants from 10 months onward, (2) maternal pointing frequency was not associated with infant pointing frequency at any age, (3) infants' point following abilities to targets behind their visual fields was positively associated with their pointing frequency at 12 months, after pointing had already emerged around 10 months. Findings suggest that family SES impacts infants' pointing development more generally, not just through maternal pointing. The association between pointing and following points to targets behind, but not in front, suggests that a higher level of referential understanding emerges after, and perhaps through the production of pointing.     

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.     

Pointing to Visible and Invisible Targets

We investigated how the visibility of targets influenced the type of point used to provide directions. In Study 1, we asked 605 passersby in three localities for directions to well-known local landmarks. When that landmark was in plain view behind the requester, most respondents pointed with their index fingers, and few respondents pointed more than once. In contrast, when the landmark was not in view, respondents pointed initially with their index fingers, but often elaborated with a whole-hand point. In Study 2, we covertly filmed the responses from 157 passersby we approached for directions, capturing both verbal and gestural responses. As in Study 1, few respondents produced more than one gesture when the target was in plain view and initial points were most likely to be index finger points. Thus, in a Western geographical context in which pointing with the index finger is the dominant form of pointing, a slight change in circumstances elicited a preference for pointing with the whole hand when it was the second or third manual gesture in a sequence.     

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.     

Social motivation predicts gaze following between 6 and 14 months

Infants vary in their ability to follow others’ gazes, but it is unclear how these individual differences emerge. We tested whether social motivation levels in early infancy predict later gaze following skills. We longitudinally tracked infants’ (N = 82) gazes and pupil dilation while they observed videos of a woman looking into the camera simulating eye contact (i.e., mutual gaze) and then gazing toward one of two objects, at 2, 4, 6, 8, and 14 months of age. To improve measurement validity, we used confirmatory factor analysis to combine multiple observed measures to index the underlying constructs of social motivation and gaze following. Infants’ social motivation—indexed by their speed of social orienting, duration of mutual gaze, and degree of pupil dilation during mutual gaze—was developmentally stable and positively predicted the development of gaze following—indexed by their proportion of time looking to the target object, first object look difference scores, and first face-to-object saccade difference scores—from 6 to 14 months of age. These findings suggest that infants’ social motivation likely plays a role in the development of gaze following and highlight the use of a multi-measure approach to improve measurement sensitivity and validity in infancy research.     

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.     

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.     

Early social referencing predicts object mastery motivation in infancy: Social antecedents of object mastery motivation

The researchers sought to understand the typical development of social referencing and object mastery motivation in infancy and to determine the relationship between social referencing and object mastery behaviors in infants from 7 to 22 months of age. The study included 36 infants who were followed as part of a longitudinal study of at-risk infants but were not determined to need care in the neonatal intesive care unit at birth. Both mastery behaviors of persistence and success showed a statistically significant effect of age, while social behaviors remained stable from 7 to 22 months. Social behaviors at 7 and 10 months were correlated with persistence at 22 months and success at 16 to 22 months demonstrating that early social referencing predicts object mastery behaviors in later infancy. Further research should determine if this trend extends to early childhood.     

Parental Speech at 6 Months Predicts Joint Attention at 12 Months

In a prospective longitudinal study of a representative community sample (N = 264), mothers' references to infants' mental states were coded during a topic‐sharing task in the home at 6 months. Joint attention behaviour was assessed in the laboratory at 12 months. Individual joint attention skills (gaze following, gaze alternating, and declarative pointing) were significantly inter‐correlated, with a single factor accounting for 68% of the variance. Mothers' references to infants' mental states at 6 months predicted infants' joint attention at 12 months. The association was not explained by sociodemographic characteristics of the family, the mother's mental state, or by the quantity or acoustic properties of her speech. However, variability in pitch of maternal speech was an independent predictor of the infants' later joint attention skills. Taken together, these findings suggest that mothers' infant‐directed speech fosters infants' attentive participation in topic‐sharing interactions, which in turn provide an important arena in which joint attention skills develop over the first year of life.     

Intention or Attention Before Pointing: Do Infants’ Early Holdout Gestures Reflect Evidence of a Declarative Motive?

Gestures are the first signs of intentional communication within prelinguistic infants and can reflect various motives, including a declarative motive to share attention and interest. The ability to use gestures declaratively has been linked to later language development; therefore, it is important to understand the origins of this motive. Previous research has focused on the use of declarative pointing at around 12 months; however, other potential forms of declarative communication, such as holdout gestures, are yet to be studied in detail. The purpose of this study was to examine whether from 10 months, infants use holdouts declaratively. We elicited holdouts from 36 infants and then reacted to these gestures in four different conditions: (1) joint attention: shared interest; (2) infant attention: attended to infant; (3) toy attention: attended to toy; (4) ignore: gesture was not attended to. Infants’ behavioral responses were recorded. When the experimenter engaged in joint attention, infants were significantly more likely to display a positive attitude and produced fewer re‐engagement attempts. In contrast, the three non‐joint attention conditions displayed significantly higher negative attitudes and attempts to re‐engage the experimenter. We conclude that infants display declarative communication prior to 12 months, resetting the age at which these more complex skills emerge.     

Exploring the relation between maternal mind‐mindedness and children’s symbolic play: A longitudinal study from 6 to 18 months

Relations between mothers’ mind‐mindedness (appropriate attunement to their infants’ internal states) at 6 and 12 months and infants’ early symbolic play during infant–mother pretense at 12 and 18 months were investigated in a sample of 43 mothers and infants. Mothers’ appropriate mind‐related comments were associated with average level, length, complexity, and maturity level of symbolic play. Specific sub‐categories of appropriate mind‐related comments were identified as independent predictors of children's symbolic play. Appropriate comments about desires and cognitions at 6 months were associated with average level and length of episodes, as well as with maturity level of symbolic play at 12 months. Longitudinal stability in the appropriateness and content of mothers’ mind‐related comments was also investigated. The results are discussed in terms of the proposal that attunement to specific types of internal state should vary as a function of infant age in order to index mind‐mindedness.     

The Other‐Race Effect in a Longitudinal Sample of 3‐, 6‐ and 9‐Month‐Old Infants: Evidence of a Training Effect

We investigated the development of the other‐race effect “ORE” in a longitudinal sample of 3‐, 6‐, and 9‐month‐old Caucasian infants. Previous research using cross‐sectional samples has shown an unstable ORE at 3 months, an increase at 6 months and full development at 9 months. In Experiment 1, we tested whether 9‐month‐olds showed the ORE with Caucasian and African faces. As expected, the 9‐month‐olds discriminated faces within their own ethnicity (Caucasian) but not within the unfamiliar ethnicity (African). In months. In Experiment 2, we longitudinally tested infants at 3, 6, and 9 months by presenting either the Caucasian or the African faces used in Experiment 1. In contrast to previous cross‐sectional studies and Experiment 1, we found that infants discriminated between all stimuli. Hence, we did not find the ORE in this longitudinal study even at 9 months. We assume that the infants in our longitudinal study showed no ORE because of previous repetitive exposure to African faces at 3 and 6 months. We argue that only a few presentations of faces from other ethnic categories sufficiently slow the development of the ORE.     

Effects of Maternal Responsiveness on Infant Responsiveness and Behavior in the Still‐Face Task

The effects of maternal responsiveness on infant responsiveness and behavior in the Still‐Face Task were longitudinally examined through infants' first 3 months. Maternal vocal responsiveness and infant vocal and smiling responsiveness significantly increased when infants were 2 months of age. Mothers showed continuity of individual differences in vocal responsiveness from the infants' newborn period. Maternal responsiveness predicted infant responsiveness within and across sessions. Compared with infants with low‐responsive mothers, infants with high‐responsive mothers were more attentive and affectively engaged during the Still‐Face Task from 1 month of age. Infants with high‐responsive mothers discriminated between the task phases with their smiling at 1 month, a month before infants with low‐responsive mothers did so. Infants in both groups discriminated between the phases with their attention and nondistress vocalizations throughout their first 3 months. Results suggest that maternal responsiveness influences infant responsiveness and facilitates infants' engagement and expectations for social interaction.     

Individual Differences in Infants’ Joint Attention Behaviors With Mother and a New Social Partner

Relations between infant–mother attachment security at 15 months and infants’ (N = 206) joint attention behaviors (a) with an experimenter at 8 and 15 months, and (b) with their mothers at 15 months were investigated. No concurrent or longitudinal relations were observed between attachment security and infants’ tendency to respond to an experimenter’s bids for joint attention. Higher levels of initiating joint attention with an experimenter at 15 months were associated with insecure‐avoidant attachment. Insecure‐avoidant attachment was also associated with lower scores for initiating high‐level joint attention behaviors (pointing, showing, and giving) with the mother at age 15 months. The fact that security‐related differences in initiating joint attention with an experimenter were observed only once the attachment relationship was consolidated suggests that (a) attachment security may influence infants’ active engagement with new social partners, and (b) insecure‐avoidant infants may compensate for reduced social contact with the caregiver by initiating more interaction with other social partners.     

The early development of tempo adjustment and synchronization during joint drumming: A study of 18- to 42-month-old children

Humans have a unique ability to coordinate their rhythmic behaviors with those of others. Previous studies have demonstrated the early development of spontaneous responses to external rhythmic stimuli; however, there is little evidence regarding when and how infants begin to adjust their movement tempo and synchronize it with that of others, due to the difficulty of detecting continuous rhythmic movements of infants in a laboratory setting. In the current study, we analyzed children in age-groups of 18, 30, and 42 months and adapted a joint-drumming task used by Kirschner and Tomasello (Journal of Experimental Child Psychology, 2009, 102, 299–314). The children were enticed to play the drum under four conditions (Speed: 400 or 600 ms ISI; Partner: mother or robot). The results demonstrated that children's ability to adjust their tempo and synchronize with that of 600 ms ISI, which is slower than the spontaneous motor tempo of children at these ages, starts to develop at around 30-month-olds. We also found early evidence of this ability in 18-month-old infants who drummed with their mother. These findings indicate that children's ability for rhythmic coordination develops dynamically between 18 and 30 months of age, and a child's social partner plays an important role in facilitating this development.