The temporal structure of parent talk to toddlers about objects

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.

Annual Research Review: 'There, the dance is - at the still point of the turning world' - dynamic systems perspectives on coregulation and dysregulation during early development

During development we transition from coregulation (where regulatory processes are shared between child and caregiver) to self-regulation. Most early coregulatory interactions aim to manage fluctuations in the infant's arousal and alertness; but over time, coregulatory processes become progressively elaborated to encompass other functions such as sociocommunicative development, attention and executive control. The fundamental aim of coregulation is to help maintain an optimal 'critical state' between hypo- and hyperactivity. Here, we present a dynamic framework for understanding child-caregiver coregulatory interactions in the context of psychopathology. Early coregulatory processes involve both passive entrainment, through which a child's state entrains to the caregiver's, and active contingent responsiveness, through which the caregiver changes their behaviour in response to behaviours from the child. Similar principles, of interactive but asymmetric contingency, drive joint attention and the maintenance of epistemic states as well as arousal/alertness, emotion regulation and sociocommunicative development. We describe three ways in which active child-caregiver regulation can develop atypically, in conditions such as Autism, ADHD, anxiety and depression. The most well-known of these is insufficient contingent responsiveness, leading to reduced synchrony, which has been shown across a range of modalities in different disorders, and which is the target of most current interventions. We also present evidence that excessive contingent responsiveness and excessive synchrony can develop in some circumstances. And we show that positive feedback interactions can develop, which are contingent but mutually amplificatory child-caregiver interactions that drive the child further from their critical state. We discuss implications of these findings for future intervention research, and directions for future work.

Can Infants Retain Statistically Segmented Words and Mappings Across a Delay?

Infants are sensitive to statistics in spoken language that aid word-form segmentation and immediate mapping to referents. However, it is not clear whether this sensitivity influences the formation and retention of word-referent mappings across a delay, two real-world challenges that learners must overcome. We tested how the timing of referent training, relative to familiarization with transitional probabilities (TPs) in speech, impacts English-learning 23-month-olds' ability to form and retain word-referent mappings. In Experiment 1, we tested infants' ability to retain TP information across a 10-min delay and use it in the service of word learning. Infants successfully mapped high-TP but not low-TP words to referents. In Experiment 2, infants readily mapped the same words even when they were unfamiliar. In Experiment 3, high- and low-TP word-referent mappings were trained immediately after familiarization, and infants readily remembered these associations 10 min later. In sum, although 23-month-old infants do not need strong statistics to map word forms to referents immediately, or to remember those mappings across a delay, infants are nevertheless sensitive to these statistics in the speech stream, and they influence mapping after a delay. These findings suggest that, by 23 months of age, sensitivity to statistics in speech may impact infants' language development by leading word forms with low coherence to be poorly mapped following even a short period of consolidation.

Within arms reach: Physical proximity shapes mother-infant language exchanges in real-time

During everyday interactions, mothers and infants achieve behavioral synchrony at multiple levels. The ebb-and-flow of mother-infant physical proximity may be a central type of synchrony that establishes a common ground for infant-mother interaction. However, the role of proximity in language exchanges is relatively unstudied, perhaps because structured tasks-the common setup for observing infant-caregiver interactions-establish proximity by design. We videorecorded 100 mothers (U.S. Hispanic N = 50, U.S. Non-Hispanic N = 50) and their 13- to 23-month-old infants during natural activity at home (1-to-2 h per dyad), transcribed mother and infant speech, and coded proximity continuously (i.e., infants and mother within arms reach). In both samples, dyads entered proximity in a bursty temporal pattern, with bouts of proximity interspersed with bouts of physical distance. As hypothesized, Non-Hispanic and Hispanic mothers produced more words and a greater variety of words when within arms reach than out of arms reach. Similarly, infants produced more utterances that contained words when close to mother than when not. However, infants babbled equally often regardless of proximity, generating abundant opportunities to play with sounds. Physical proximity expands opportunities for language exchanges and infants' communicative word use, although babies accumulate massive practice babbling even when caregivers are not proximal.

Does the public know what researchers know? Perceived task difficulty impacts adults' intuitions about children's early word learning

The present study examined adults' understanding of children's early word learning. Undergraduates, non-parents, parents, and Speech-Language Pathologists (N = 535, 74% female, 56% White) completed a survey with 11 word learning principles from the perspective of a preschooler. Questions tested key principles from early word learning research. For each question, participants were prompted to select an answer based on the perspective of a preschooler. Adults demonstrated aligned intuitions for all principles except those derived from domain-general theories, regardless of experience with language development (Experiment 1). Experiment 2 revealed that perceived difficulty of a task for a preschooler impacted adults' reasoning about word learning processes. Experiment 3 ruled out level of confidence and interest as mechanisms to explain the results. These results highlight disconnects in knowledge between the cognitive development research community and the general public. Therefore, efforts must be made to communicate scientific findings to the broader non-academic community, emphasizing children's ability to excel at word learning in the face of task difficulty.

Sampling statistics are like story creation: a network analysis of parent-toddler exploratory play

Actions in the world elicit data for learning and do so in a stream of interconnected events. Here, we provide evidence on how toddlers with their parent sample information by acting on toys during exploratory play. We observed 10 min of free-flowing and unconstrained object exploration of by toddlers (mean age 21 months) and parents in a room with many available objects (n = 32). Borrowing concepts and measures from the study of narratives, we found that the toy selections are not a string of unrelated events but exhibit a suite of what we call coherence statistics: Zipfian distributions, burstiness and a network structure. We discuss the transient memory processes that underlie the moment-to-moment toy selections that create this coherence and the role of these statistics in the development of abstract and generalizable systems of knowledge. This article is part of the theme issue 'Concepts in interaction: social engagement and inner experiences'.

Vocal communication is tied to interpersonal arousal coupling in caregiver-infant dyads

It has been argued that a necessary condition for the emergence of speech in humans is the ability to vocalise irrespective of underlying affective states, but when and how this happens during development remains unclear. To examine this, we used wearable microphones and autonomic sensors to collect multimodal naturalistic datasets from 12-month-olds and their caregivers. We observed that, across the day, clusters of vocalisations occur during elevated infant and caregiver arousal. This relationship is stronger in infants than caregivers: caregivers vocalisations show greater decoupling with their own states of arousal, and their vocal production is more influenced by the infant's arousal than their own. Different types of vocalisation elicit different patterns of change across the dyad. Cries occur following reduced infant arousal stability and lead to increased child-caregiver arousal coupling, and decreased infant arousal. Speech-like vocalisations also occur at elevated arousal, but lead to longer-lasting increases in arousal, and elicit more parental verbal responses. Our results suggest that: 12-month-old infants' vocalisations are strongly contingent on their arousal state (for both cries and speech-like vocalisations), whereas adults' vocalisations are more flexibly tied to their own arousal; that cries and speech-like vocalisations alter the intra-dyadic dynamics of arousal in different ways, which may be an important factor driving speech development; and that this selection mechanism which drives vocal development is anchored in our stress physiology.