Preverbal infants produce more protophones with artificial objects compared to natural objects.

Protophones are considered to be precursors of speech. These vocalizations have been notably discussed in relation to toys and their importance for developing language skills. However, little is known about how natural objects, compared to artificial objects, may affect protophone production, an approach that could additionally help reconstruct how language evolved. In the current study, we examined protophone production in 58 infants (4-18 months) while interacting with their caregivers when using natural objects, household items, and toys. The infants were recorded in their home environment, in a rural area in Zambia. The results showed that the infants produced significantly fewer protophones when using natural objects than when using household items or toys. Importantly, this pattern was found only for the younger preverbal infants, and there was no indication in the data that the level of caregiver responsiveness differed with regard to the object type. Furthermore, the infants of the present work selected primarily the household items when exposed to both natural objects and household items. These findings suggest that natural objects are less likely to promote protophone production and, consequently, language skill development than artificial objects in preverbal infants, who seem to favor the latter, perhaps due to their features designed for specific functional purposes. Furthermore, these findings provide empirical evidence that the use of complex tools in social interactions may have helped to promote the evolution of language among hominins.

Interactional preludes to infants' affective climax - Mother-infant interaction around infant smiling in two cultures.

Due to limited research on cross-cultural similarities and differences in the development of infant smiling, the main goals of this study were to analyze, first, the development of infants' bouts of intense smiling during their third month and, second, the interactional preludes to infants' affective climax in two cultural contexts, namely Kichwa families from the Ecuadorian Andes region and educated urban middle-class families from Münster, Germany, which differ concerning their cultural models on infant smiling. Based on a longitudinal, naturalistic study design, mother-infant interaction in Kichwa (n = 10) and Münster (n = 10) families was analyzed when infants were 9 and 13 weeks old. Following a mixed methods approach, a quantitative analysis of infant smiling based on a 1-second interval-coding approach showed that there was a significant increase in infants' high-intensity positive affect from 9 to 13 weeks in the Münster, but not the Kichwa sample, leading to significant cross-cultural differences at 13 weeks. Complementarily, the qualitative analysis of the interactional preludes to the 66 infants' affective climaxes at 13 weeks identified two main patterns that characterized the dynamic that resulted in high-intensity positive affect and that were similar across the two cultural contexts: the first was intense and multimodal stimulation with repetition and theme variation, and the second was positively tuned and mutually contingent responsiveness, often in the form of prolonged proto-conversations between mother and infant. Overall, this open approach converged on key mechanisms underlying infant smiling, namely infants' experience of mastery based on effortful assimilation or self-efficacy, which was embedded in episodes of intersubjective coordination. Overall, these results suggest universality without uniformity; that is, similar interactional mechanisms are associated with high-intense positivity in infants, while the episodes are co-constructed differently in different dyads and high-intense positivity varies in significance and frequency across cultures.

Improving the generalizability of infant psychological research: The ManyBabies model.

Yarkoni's analysis clearly articulates a number of concerns limiting the generalizability and explanatory power of psychological findings, many of which are compounded in infancy research. ManyBabies addresses these concerns via a radically collaborative, large-scale and open approach to research that is grounded in theory-building, committed to diversification, and focused on understanding sources of variation.

Taking Up an Active Role: Emerging Participation in Early Mother-Infant Interaction during Peekaboo Routines.

Dynamical systems approaches to social coordination underscore how participants' local actions give rise to and maintain global interactive patterns and how, in turn, they are also shaped by them. Developmental research can deliver important insights into both processes: (1) the stabilization of ways of interacting, and (2) the gradual shaping of the agentivity of the individuals. In this article we propose that infants' agentivity develops out of participation, i.e., acting a part in an interaction system. To investigate this development this article focuses on the ways in which participation in routinized episodes may shape infant's agentivity in social events. In contrast to existing research addressing more advanced forms of participating in social routines, our goal was to assess infants' early participation as evidence of infants' agentivity. In our study, 19 Polish mother-infant dyads were filmed playing peekaboo when the infants were 4 and 6 months of age. We operationalized infants' participation in the peekaboo in terms of their use of various behaviors across modalities during specific phases of the game: We included smiles, vocalizations, and attempts to cover and uncover themselves or their mothers. We hypothesized that infants and mothers would participate actively in the routine by regulating their behavior so as to adhere to the routine format. Furthermore, we hypothesized that infants who experienced more scaffolding would be able to adopt a more active role in the routine. We operationalized scaffolding as mothers' use of specific peekaboo structures that allowed infants to anticipate when it was their turn to act. Results suggested that infants as young as 4 months of age engaged in peekaboo and took up turns in the game, and that their participation increased at 6 months of age. Crucially, our results suggest that infants' behavior was organized by the global structure of the peekaboo game, because smiles, vocalizations, and attempts to uncover occurred significantly more often during specific phases rather than being evenly distributed across the whole interaction. Furthermore, the way mothers structured the game at 4 months predicted infant participation at both 4 and 6 months of age.

Verbs in Mothers' Input to Six-Month-Olds: Synchrony between Presentation, Meaning, and Actions Is Related to Later Verb Acquisition.

In embodied theories on language, it is widely accepted that experience in acting generates an expectation of this action when hearing the word for it. However, how this expectation emerges during language acquisition is still not well understood. Assuming that the intermodal presentation of information facilitates perception, prior research had suggested that early in infancy, mothers perform their actions in temporal synchrony with language. Further research revealed that this synchrony is a form of multimodal responsive behavior related to the child's later language development. Expanding on these findings, this article explores the relationship between action-language synchrony and the acquisition of verbs. Using qualitative and quantitative methods, we analyzed the coordination of verbs and action in mothers' input to six-month-old infants and related these maternal strategies to the infants' later production of verbs. We found that the verbs used by mothers in these early interactions were tightly coordinated with the ongoing action and very frequently responsive to infant actions. It is concluded that use of these multimodal strategies could significantly predict the number of spoken verbs in infants' vocabulary at 24 months.

Beyond mechanistic interaction: value-based constraints on meaning in language.

According to situated, embodied, and distributed approaches to cognition, language is a crucial means for structuring social interactions. Recent approaches that emphasize this coordinative function treat language as a system of replicable constraints on individual and interactive dynamics. In this paper, we argue that the integration of the replicable-constraints approach to language with the ecological view on values allows for a deeper insight into processes of meaning creation in interaction. Such a synthesis of these frameworks draws attention to important sources of structuring interactions beyond the sheer efficiency of a collective system in its current task situation. Most importantly, the workings of linguistic constraints will be shown as embedded in more general fields of values, which are realized on multiple timescales. Because the ontogenetic timescale offers a convenient window into the emergence of linguistic constraints, we present illustrations of concrete mechanisms through which values may become embodied in language use in development.