Sociocultural settings influence the emergence of prelinguistic deictic gestures

Referential interactions of Turkish-learning children with their caregivers about non-absent objects: integration of non-verbal devices and prior discourse

This paper examines the way children younger than two use non-verbal devices (i.e., deictic gestures and communicative functional acts) and pay attention to discourse status (i.e., prior mention vs. newness) of referents in interactions with caregivers. Data based on semi-naturalistic interactions with caregivers of four children, at ages 1;00, 1;05, and 1;09, are analyzed. We report that children employ different types of non-verbal devices to supplement their inadequate referential forms before gaining mastery in language. By age 1;09, children show sensitivity to discourse status by using deictic gestures to accompany their non-lexical forms for new referents. A comparison of children's patterns with those in the input they receive reveals that caregivers choose their referential forms in accordance with discourse status information and tend to use different types of non-verbal devices to accompany their lexical and non-lexical referential forms. These results show that non-verbal devices play an important role in early referential discourse.

Cultural diversification of communicative gestures through early childhood: A comparison of children in English-, German-, and Chinese- speaking families

Previous literature has demonstrated cultural differences in young children's use of communicative gestures, but the results were mixed depending on which gestures were measured and what age of children were involved. This study included variety of different types of gestures and examined whether children's use of communicative gestures varies by their cultural backgrounds and ages. 714 parents of children (6-36 months old) from U.S.A. English-, German-, and Taiwan Chinese- speaking countries completed the questionnaire on their children's use of each gesture described in the survey. We used logistic regressions to examine the effect of children's culture and age, and the interaction effect (culture×age). Children were more likely to use all gestures except reaching, showing, and smacking lips for "yum, yum" as their age increases. In addition, there were gestures that showed significantly different probabilities across children's cultural backgrounds. A significant interaction effect was shown for five gestures: reaching, showing, pointing, arms up to be picked up, and "quiet" gesture. Results suggest that the influence of culture on young children's communication emerges from infancy.

Child-Directed Speech Is Infrequent in a Forager-Farmer Population: A Time Allocation Study

This article provides an estimation of how frequently, and from whom, children aged 0-11 years (Ns between 9 and 24) receive one-on-one verbal input among Tsimane forager-horticulturalists of lowland Bolivia. Analyses of systematic daytime behavioral observations reveal < 1 min per daylight hour is spent talking to children younger than 4 years of age, which is 4 times less than estimates for others present at the same time and place. Adults provide a majority of the input at 0-3 years of age but not afterward. When integrated with previous work, these results reveal large cross-cultural variation in the linguistic experiences provided to young children. Consideration of more diverse human populations is necessary to build generalizable theories of language acquisition.

The Role of Ontogeny in the Evolution of Human Cooperation

To explain the evolutionary emergence of uniquely human skills and motivations for cooperation, Tomasello et al. (2012, in Current Anthropology 53(6):673-92) proposed the interdependence hypothesis. The key adaptive context in this account was the obligate collaborative foraging of early human adults. Hawkes (2014, in Human Nature 25(1):28-48), following Hrdy (Mothers and Others, Harvard University Press, 2009), provided an alternative account for the emergence of uniquely human cooperative skills in which the key was early human infants' attempts to solicit care and attention from adults in a cooperative breeding context. Here we attempt to reconcile these two accounts. Our composite account accepts Hrdy's and Hawkes's contention that the extremely early emergence of human infants' cooperative skills suggests an important role for cooperative breeding as adaptive context, perhaps in early Homo. But our account also insists that human cooperation goes well beyond these nascent skills to include such things as the communicative and cultural conventions, norms, and institutions created by later Homo and early modern humans to deal with adult problems of social coordination. As part of this account we hypothesize how each of the main stages of human ontogeny (infancy, childhood, adolescence) was transformed during evolution both by infants' cooperative skills "migrating up" in age and by adults' cooperative skills "migrating down" in age.

Young children communicate their ignorance and ask questions

Children acquire information, especially about the culture in which they are being raised, by listening to other people. Recent evidence has shown that young children are selective learners who preferentially accept information, especially from informants who are likely to be representative of the surrounding culture. However, the extent to which children understand this process of information transmission and actively exploit it to fill gaps in their knowledge has not been systematically investigated. We review evidence that toddlers exhibit various expressive behaviors when faced with knowledge gaps. They look toward an available adult, convey ignorance via nonverbal gestures (flips/shrugs), and increasingly produce verbal acknowledgments of ignorance ("I don't know"). They also produce comments and questions about what their interlocutors might know and adopt an interrogative stance toward them. Thus, in the second and third years, children actively seek information from interlocutors via nonverbal gestures or verbal questions and display a heightened tendency to encode and retain such sought-after information.

Cultural transmission through infant signs: Objects and actions in U.S. and Taiwan

Infant signs are intentionally taught/learned symbolic gestures which can be used to represent objects, actions, requests, and mental state. Through infant signs, parents and infants begin to communicate specific concepts earlier than children's first spoken language. This study examines whether cultural differences in language are reflected in children's and parents' use of infant signs. Parents speaking East Asian languages with their children utilize verbs more often than do English-speaking mothers; and compared to their English-learning peers, Chinese children are more likely to learn verbs as they first acquire spoken words. By comparing parents' and infants' use of infant signs in the U.S. and Taiwan, we investigate cultural differences of noun/object versus verb/action bias before children's first language. Parents reported their own and their children's use of first infant signs retrospectively. Results show that cultural differences in parents' and children's infant sign use were consistent with research on early words, reflecting cultural differences in communication functions (referential versus regulatory) and child-rearing goals (independent versus interdependent). The current study provides evidence that intergenerational transmission of culture through symbols begins prior to oral language.

Infant engagement and early vocabulary development: a naturalistic observation study of Mozambican infants from 1;1 to 2;1

This study analyzes how others engage rural and urban Mozambican infants during naturalistic observations, and how the proportion of time spent in different engagements relates to infants' language development over the second year of life. Using an extended version of Bakeman and Adamson's (1984) categorization of infant engagement, we investigated to what extent a detailed analysis of infant engagement can contribute to our understanding of vocabulary development in natural settings. In addition, we explored how the different infant engagements relate to vocabulary size, and how these differ between the two communities. Results show that rural infants spend significantly more time in forms of solitary engagement, whereas urban infants spend more time in forms of triadic joint engagement. In regard to correlations with reported productive vocabulary, we find that dyadic persons engagement (i.e. interactions not about concrete objects) has positive correlations with vocabulary measures in both rural and urban communities. In addition, we find that triadic coordinated joint attention has a positive relationship with vocabulary in the urban community, but a contrasting negative correlation with vocabulary in the rural community. These similarities and differences are explained, based upon the parenting beliefs and socialization practices of different prototypical learning environments. Overall, this study concludes that the extended categorization provides a valuable contribution to the analysis of infant engagement and their relation to language acquisition, especially for analyzing naturalistic observations as compared to semi-structured studies. Moreover, with respect to vocabulary development, Mozambican infants appear to benefit strongest from dyadic Persons engagement, while they do not necessarily benefit from joint attention, as tends to be the case for children from industrial, developed communities.

Infants' behavioral styles in joint attention situations and parents' socio-economic status

In this study the eco-cultural model of parenting (Keller, H. (2007). Cultures of infancy. Mahwah, NJ: Erlbaum) was applied to the study of joint attention behavior of children from families with different socio-economic status (SES). It was hypothesized that infants' early communication styles would differ with SES reflecting more independent or interdependent interactions with their caregivers. It was also hypothesized that infants would use the same types of behaviors whether they have declarative or imperative communication goals. The Early Social Communication Scales (ESCS, Mundy et al., 2003) was administered to 103 typically developing infants of 12 months (approximately half of them siblings of children with autism). A factor analysis, yielding four behavioral factors, namely pointing, eye contact, actions and following points, confirmed the hypothesis that infants use behaviors consistently across situations independent of their communicative intent. MANOVAs (comprising parental education and income) revealed that higher SES infants showed actions more frequently in the ESCS whereas lower SES infants followed experimenter's points more frequently. The results are discussed in the context of presumably differing socialization goals for infants and the divergent contribution of parental education and income that seem to have additive contribution to some factors (actions, following points) but divergent contributions to others (pointing, eye contact).

The Importance of Development for Comparative Primatology

It is a truism to say that primates develop, but it is also important to acknowledge that development occurs across many domains, including motor behavior, socioemotional behavior, communication, and cognition. In this review, we focus on those aspects of development that impact social cognition outcomes in infancy. Triadic engagements, such as those of joint attention, cooperation, and intentional communication, develop in the first year of life in chimpanzees and humans. Joint attention, for example, occurs when infants coordinate their attention to a social partner while also attending to an object or event. Hominoids are strongly influenced by experiences during early development, especially experiences that are foundational for these coordinated triadic engagements. Purported species differences in triadic engagements are highlighted in current evolutionary theories of primate social cognition, but conclusions about species differences are unfounded when development is ignored. Developmental experiences must be matched, controlled, or systematically varied in experimental designs that make cross-species comparisons. Considerations of development, across species and across rearing experiences, would contribute to more accurate evolutionary theories of primate social cognition.

Infants Understand How Testimony Works

Children learn about the world from the testimony of other people, often coming to accept what they are told about a variety of unobservable and indeed counterintuitive phenomena. However, research on children's learning from testimony has paid limited attention to the foundations of that capacity. We ask whether those foundations can be observed in infancy. We review evidence from two areas of research: infants' sensitivity to the emotional expressions of other people; and their capacity to understand the exchange of information through non-verbal gestures and vocalization. We conclude that a grasp of the bi-directional exchange of information is present early in the second year. We discuss the implications for future research, especially across different cultural settings.

Two sources of meaning in infant communication: preceding action contexts and act-accompanying characteristics

How do infants communicate before they have acquired a language? This paper supports the hypothesis that infants possess social-cognitive skills that run deeper than language alone, enabling them to understand others and make themselves understood. I suggested that infants, like adults, use two sources of extralinguistic information to communicate meaningfully and react to and express communicative intentions appropriately. In support, a review of relevant experiments demonstrates, first, that infants use information from preceding shared activities to tailor their comprehension and production of communication. Second, a series of novel findings from our laboratory shows that in the absence of distinguishing information from preceding routines or activities, infants use accompanying characteristics (such as prosody and posture) that mark communicative intentions to extract and transmit meaning. Findings reveal that before infants begin to speak they communicate in meaningful ways by binding preceding and simultaneous multisensory information to a communicative act. These skills are not only a precursor to language, but also an outcome of social-cognitive development and social experience in the first year of life.

Putting the "Joy" in joint attention: affective-gestural synchrony by parents who point for their babies

Despite a growing body of work examining the expression of infants' positive emotion in joint attention contexts, few studies have examined the moment-by-moment dynamics of emotional signaling by adults interacting with babies in these contexts. We invited 73 parents of infants (three fathers) to our laboratory, comprising parent-infant dyads with babies at 6 (n = 15), 9 (n = 15), 12 (n = 15), 15 (n = 14), and 18 (n = 14) months of age. Parents were asked to sit in a chair centered on the long axis of a room and to point to distant dolls (2.5 m) when the dolls were animated, while holding their children in their laps. We found that parents displayed the highest levels of smiling at the same time that they pointed, thus demonstrating affective/referential synchrony in their infant-directed communication. There were no discernable differences in this pattern among parents with children of different ages. Thus, parents spontaneously encapsulated episodes of joint attention with positive emotion.

Differences in the nonverbal requests of great apes and human infants

This study investigated how great apes and human infants use imperative pointing to request objects. In a series of three experiments (infants, N = 44; apes, N = 12), subjects were given the opportunity to either point to a desired object from a distance or else to approach closer and request it proximally. The apes always approached close to the object, signaling their request through instrumental actions. In contrast, the infants quite often stayed at a distance, directing the experimenters' attention to the desired object through index-finger pointing, even when the object was in the open and they could obtain it by themselves. Findings distinguish 12-month-olds' imperative pointing from ontogenetic and phylogenetic earlier forms of ritualized reaching.