Cortisol Reactivity, Maternal Sensitivity, and Infant Preference for Mother's Familiar Face and Rhyme in 6-Month-Old Infants

Developmental cascades of vocal turn-taking connect prelinguistic vocalizing with early language

Conversational turn-taking is ubiquitously found in caregiver-infant interactions, and robustly predictive of infant communicative development. Over the first year, infants take quick adult-like vocal turns with caregivers. Many studies have documented the consistency of caregiver responsiveness and its influence on infant rapid language growth. However, few have examined how caregiver responsiveness facilitates extended vocal turn-taking in real-time with infants over the first year. The influence of prelinguistic vocal turn-taking on the emergence of language has also been under-investigated. We analyzed free-play sessions of 30 caregivers and their infants at both 5 and 10 months, and obtained infant language outcomes at 18 months. We examined the developmental consistency (group-level continuity and dyad-order stability) and change of infant volubility, caregiver responses to babbling in vocal, non-vocal and multimodal modalities, and the influence of modality on caregiver-infant vocal turn-taking. Caregiver contingent responsiveness to infant babbling at 5 months predicted vocal turn-taking at 10 months. Developmental increases in prelinguistic vocalizing and vocal turn-taking from 5 to 10 months predicted infant language outcomes at 18 months. At both 5 and 10 months, caregiver vocal responses were more effective in extending turn-taking than non-vocal or multimodal responses. In summary, prelinguistic vocal turn-taking, facilitated by caregiver vocal responsiveness, is positively related to the emergence of early language.

Infant visual preference for the mother's face and longitudinal associations with emotional reactivity in the first year of life

Past research has focused on infants' visual preference for the mother's face, however it is still unknown how these responses change over time and what factors associate with such changes. A longitudinal study (N ~ 60) was conducted to investigate the trajectories of infant visual preference for the mother's face and how these are related to the development of emotional reactivity in the first year of life. Two face stimuli (i.e., the infant's mother and a consistent stranger face) were used in a visual preference task at 2 weeks, 4, 6, and 9 months of age. At each time point, mothers were asked to complete a measure of infant temperament via standardised questionnaires. Our results show that while at 2 weeks, 4 months and 9 months of age infants looked equally at both faces, infants at 6 months looked significantly longer at their mother's face. We also observed prospective associations with emotional reactivity variables so that infants who looked longer at the mother's face at 6 months showed higher falling reactivity, i.e. a better ability to recover from distress, at 9 months. We discuss these findings in light of the roles that both infant development and the caregiver play in emerging emotion regulation capacities during the first year of life.

"Does your baby watch TV?": The associations between at-home TV watching and laboratory challenge cortisol are different for young infants and their mothers

This longitudinal study examined associations between at-home TV watching and the biological stress response (cortisol) during a laboratory infant cognitive challenge task in 240 3- and 5-month infants and their mothers. Cortisol levels were lower in mothers of 5-month-old infants whose infants were exposed to TV at home, compared to mothers of infants that were not TV-exposed. Cortisol patterns were different across three laboratory sampling intervals for 3-month-old infants as a function of TV watching, revealing a sharp increase in laboratory cortisol only for infants who were exposed to TV at home. In contrast, there was no effect of TV exposure in 5-month-old infants' cortisol. Infant temperament and demographic measures were included as control variables in regression models to predict maternal and infant cortisol. At 3 months, for the T3 cortisol sampling interval, and at 5 months across all three sampling intervals, maternal cortisol levels were significantly predicted by infant TV exposure after accounting for variance due to these control variables. Our findings show the strong influence of the infant TV-exposure factor in the biological stress response of mothers of young infants, and suggest that infant TV exposure may influence self-regulation in 3-month-old infants.

Caregiver and Young Child Biological Attunement In Distress Contexts: A Systematic Review and Narrative Synthesis

The objective of the current study was to systematically review the literature on caregiver-child biological attunement within distress contexts during the first three years of life. A total of 9932 unique abstracts were identified through Medline, Embase, PsycINFO, CINAHL, and Scopus databases. Thirty-six studies provided data from caregivers and their infants or toddlers within a distress paradigm, used biological indicators of distress, and assessed the relations between caregiver and child biological indicators. Findings were synthesized based on biological indicators, type of analysis, and measurement epochs pre- and post-distress. Most articles examined cortisol. Associations between caregiver and child cortisol indicators were moderate to large, though findings varied depending on the analysis used and measurement epochs examined. Many of the findings examining relations between mother and child cardiac, sAA, and EEG indicators were weak or inconsistent, likely due to the limitations of methodological approaches used to capture the complexity of the caregiver-child attunement process. Gaps in the literature and suggestions for future research are discussed.

Social Network and Behavioral Synchrony Influences On Maternal and Infant Cortisol Response

This study examined the contributions of mothers' social network stability and mother-infant behavioral synchrony on cortisol response in infants and their mothers during separation. The quality and stability of mothers' social network system and mother-infant bond have both been shown to affect infant neuroendocrine response. Yet, no studies have directly addressed how these two forms of social relationships might differentially affect infants' and mothers' neuroendocrine responses during separation. First-time mothers (N = 133) and their 3-month-old infants participated in the study. Maternal social network stability, mother-infant behavioral synchrony, and mother and infant cortisol response during an infant challenge task were assessed. Behavioral synchrony accounted for significant variance in infants' cortisol response, and after adjusting for synchrony, mothers' network stability measures did not explain variance in infant cortisol. Social network stability, but not synchrony, accounted for significant variance in mothers' cortisol response. These results demonstrate that, when mothers and infants experience brief separation, the quality of their bond is associated with a lower stress response for infants; but for mothers, it is the longevity of her social relationships outside of the mother-infant relationship context that is associated with her lower stress response.

A systematic review of caregiver-child physiological synchrony across systems: Associations with behavior and child functioning

Extensive research has established a positive association between caregiver-child behavioral synchrony and child developmental functioning. Burgeoning research examining physiological synchrony has yet to elucidate its impact for children's developing self-regulation. The objectives of this systematic review were to: 1) determine whether there is evidence that caregiver-child physiological synchrony promotes positive child development, 2) examine developmental differences in physiological synchrony and its correlates, and 3) explore whether context, risk, and/or stress influence patterns of synchrony. Sixty-nine studies met the following criteria on PubMed and PsycINFO: 1) peer-reviewed empirical articles in English that 2) examine autonomic, hypothalamic-pituitary-adrenocortical, and/or central nervous system activity 3) for caregivers and children 4) in response to a task and 5) directly examine the association between caregiver and child physiology. Findings varied based on developmental period and current behavioral context. Functional differences may exist across physiological systems and contexts. Synchrony may have different developmental consequences for dyads with and without certain risk factors. Few studies examine physiological synchrony across multiple systems or contexts, nor do they measure child characteristics associated with synchrony. Statistical and methodological challenges impede interpretation. Findings generally support the idea that physiological synchrony may support children's developing self-regulation. Longitudinal research is needed to examine child developmental outcomes over time.

Mothering revisited: A role for cortisol?

This selective review first describes the involvement of the maternal hypothalamic-pituitary-adrenal (HPA) axis during pregnancy and the postpartum period, and the relation between peripartum HPA axis function and maternal behavior, stress reactivity and emotional dysregulation in human mothers. To provide experimental background to this correlational work, where helpful, animal studies are also described. It then explores the association between HPA axis function in mothers and their infants, under ongoing non-stressful conditions and during stressful challenges, the moderating role of mothers' sensitivity and behavior in the mother-child co-regulation and the effects of more traumatic risk factors on these relations. The overarching theme being explored is that the HPA axis - albeit a system designed to function during periods of high stress and challenge - also functions to promote adaptation to more normative processes, shown in the new mother who experiences both high cortisol and enhanced attraction and attention to and recognition of, their infants and their cues. Hence the same HPA system shows positive relations with behavior at some time points and inverse ones at others. However, the literature is not uniform and results vary widely depending on the number, timing, place, and type of samplings and assessments, and, of course, the population being studied and, in the present context, the state, the stage, and the stress levels of mother and infant.

Mechanisms of Timing, Timbre, Repertoire, and Entrainment in Neuroplasticity: Mutual Interplay in Neonatal Development

Neonatal brain development relies on a combination of critical factors inclusive of genetic predisposition, attachment, and the conditions of the pre and postneonatal environment. The status of the infant’s developing brain in its most vulnerable state and the impact that physiological elements of music, silences and sounds may make in the earliest stages of brain development can enhance vitality. However, little attention has been focused on the integral aspects of the music itself. This article will support research that has hypothesized conditions of music therapeutic applications in an effort to further validate models of neurobehavioral care that have optimized conditions for growth, inclusive of recommendations leading toward the enhancement of self-regulatory behaviors.

Non-native language proficiency may influence the responsiveness of bilingual parents towards young children with autism: A short report

BACKGROUND AND AIMS

Although bilingualism is a common worldwide phenomenon, limited research has considered the experiences of children with autism growing up in bilingual environments. Here, we investigated the potential influence of parental bilingualism, and native vs. non-native language use, on responsiveness to children's communication attempts during parent-child interactions where the child had autism. Specifically, we investigated the amount of parent responses to child verbal communication (frequency) and the promptness of these responses (temporal synchrony).

METHODS

Participants were 22 monolingual and 20 bilingual parents and their children with autism aged 2-6 years, recruited from a multicultural, metropolitan city where English is the dominant language. Extending from our previous report on this sample, we identified the frequency and temporal synchrony of parent responses from filmed 10-minute free-play sessions. Monolingual parents were videoed during one free-play session in English. Bilingual parents were videoed during two free-play sessions; one in their native language and one in English. We compared the frequency and temporal synchrony of parental responses across monolingual and bilingual parent groups and, for bilingual parents, across native vs. non-native (English) language interaction samples. Finally, we examined how other measures of bilingual parents' non-native language proficiency were associated with interaction responsiveness measures.

RESULTS

When using their native language, bilingual parents demonstrated reduced frequency of responsiveness (even when controlling for opportunities provided by the child) and less temporal synchrony to child communication compared to English-speaking monolingual parents. Bilingual parents were also less frequently responsive (but not less temporally synchronous) during their native- compared to during their non-native (English) language interactions. Moreover, for bilingual parents, more frequent responsiveness to child communication bids when interacting in non-native English was associated with greater assessed English vocabulary knowledge.

CONCLUSIONS

In this sample, use of non-native English did not appear to adversely affect how often, or how quickly, bilingual parents responded to their children's verbal communication bids. However, nor did we find evidence of a native-language advantage. Rather, during English-language interactions, when these bilingual parents were responsive towards their children, this was on par with rates and timing of responsiveness shown by English-speaking monolinguals. This may partly be explained by bilinguals' non-native language proficiency, and habitual use/personal dominance patterns.

IMPLICATIONS

These data suggest no definitive drawback of non-native language use for synchronous responsiveness by bilingual parents interacting with young children with autism. However, our data also serve to highlight the complex, multifaceted nature of adult bilingualism, and indicate the need for more research - with large, well-characterised samples - to permit strong conclusions concerning how parental language-use choices may influence children's natural learning environments, including in the context of autism and developmental language impairments.

The dual nature of hypothalamic-pituitary-adrenal axis regulation in dyads of very preterm infants and their mothers

The co-regulation of the hypothalamic-pituitary-adrenal (HPA) axis in mother-infant dyads is thought to be key for infant and child development. Nonetheless, previous literature presents some inconsistencies that might at least partially be due to the presence of risk conditions and the use of different statistical approaches to measure HPA axis co-regulation. Very preterm (VPT) birth represents one of these risk conditions as the early foundation of mother-infant interaction is disrupted. Both VPT infants and their mothers present evidence of altered HPA axis regulation. Nonetheless, the comparison of mother-infant HPA axis co-regulation in VPT infants compared to full-term (FT) ones has not been previously investigated. In this study, 3-month-old (corrected age) VPT infants and FT counterparts with their mothers took part in a well-validated stress-inducing laboratory task (i.e., double Face-to-Face Still-Face, FFSF paradigm). Salivary cortisol samples were obtained before (Baseline) and after (Early reactivity, Late reactivity and Recovery) the FFSF procedure. Dyadic HPA axis co-regulation was assessed at each sample time-point (i.e., in-moment coupling) as well as across samples (i.e., in-time synchrony). Significant in-moment coupling emerged at Baseline, Late reactivity and Recovery for FT infants' dyads only. An overlying pattern of salivary cortisol trajectories emerged between mothers and infants in the VPT group, whereas a more complex pattern of reciprocal and complementary co-regulation was found for FT infants' dyads. Although both groups gave evidence of HPA axis co-regulation, dyads of VPT infants appear to be less able to adapt reciprocally and dynamically to stressful conditions. These findings suggest that multiple approaches to account for dyadic HPA axis co-regulation should be used in order to depict the complex pattern of biological rhythms coordination in mother-infant dyads.

Stress Physiology in Infancy and Early Childhood: Cortisol Flexibility, Attunement and Coordination

Research on stress physiology in infancy has assumed increasing importance due to its lifelong implications. In this review, we focus on measurement of hypothalamic-pituitary-adrenal (HPA) function, in particular, and on complementary autonomic processes. We suggest that the measure of HPA function has been overly exclusive, focusing on individual reactivity to single, pragmatically selected laboratory challenges. We advocate use of multiple, strategically chosen challenges and within-subject designs. By administering one challenge that typically does not provoke reactivity and another that does, it is possible to represent allostatic load in terms of "flexibility," the capacity to titrate response to challenge. We also recommend assessing infant reactivity in the context of the primary caregiver's physiological function. Infant-mother "attunement" is central to developmental psychology, permeating diverse developmental domains with varied consequences. A review of adrenocortical attunement suggests that attunement is a reliable process, manifest across varied populations. However, attunement appears stronger in the context of more highly stressful circumstances, such that administration of multiple, selected challenges may help evaluate the degree to which individuals titrate attunement to challenge and determine the correlates of this differential attunement. Finally, we advocate studying the "coordination" of HPA function with other aspects of stress physiology and variation in the degree of this coordination. The use of multiple stressors is important here because each stress system is differentially sensitive to different types of challenge. Therefore, use of single stressors in between-subject designs impedes full recognition of the role played by each system. Overall, we recommend measure of flexibility, attunement, and coordination in the context of multiple challenges to capture allostasis in environmental and physiological context. The simultaneous use of such inclusive and integrative metrics may yield more reliable findings than has hitherto been the case. The interrelation of these metrics can be understood in the context of the adaptive calibration model..

Why synchrony matters during mother-child interactions: a systematic review

BACKGROUND

Assessment of mother-child interactions is a core issue of early child development and psychopathology. This paper focuses on the concept of "synchrony" and examines (1) how synchrony in mother-child interaction is defined and operationalized; (2) the contribution that the concept of synchrony has brought to understanding the nature of mother-child interactions.

METHOD

Between 1977 and 2013, we searched several databases using the following key-words: "synchrony" "interaction" and "mother-child". We focused on studies examining parent-child interactions among children aged 2 months to 5 years. From the 63 relevant studies, we extracted study description variables (authors, year, design, number of subjects, age); assessment conditions and modalities; and main findings.

RESULTS

The most common terms referring to synchrony were mutuality, reciprocity, rhythmicity, harmonious interaction, turn-taking and shared affect; all terms were used to characterize the mother-child dyad. As a consequence, we propose defining synchrony as a dynamic and reciprocal adaptation of the temporal structure of behaviors and shared affect between interactive partners. Three main types of assessment methods for studying synchrony emerged: (1) global interaction scales with dyadic items; (2) specific synchrony scales; and (3) micro-coded time-series analyses. It appears that synchrony should be regarded as a social signal per se as it has been shown to be valid in both normal and pathological populations. Better mother-child synchrony is associated with familiarity (vs. unknown partner), a healthy mother (vs. pathological mother), typical development (vs. psychopathological development), and a more positive child outcomes.

DISCUSSION

Synchrony is a key feature of mother-infant interactions. Adopting an objective approach in studying synchrony is not a simple task given available assessment tools and due to its temporality and multimodal expression. We propose an integrative approach combining clinical observation and engineering techniques to improve the quality of synchrony analysis.