Dynamics of the dyad: How mothers and infants co-construct interaction spaces during object play.

Studies of dyadic interaction often examine infants' social exchanges with their caregivers in settings that constrain their physical properties (e.g., infant posture, fixed seating location for infants and adults). Methodological decisions about the physical arrangements of interaction, however, may limit our ability to understand how posture and position shape them. Here we focused on these embodied properties of dyadic interaction in the context of object play. We followed 30 mother-infant dyads across the first year of life (at 3, 6, 9, and 12 months) and observed them during 5 min of play with a standard set of toys. Using an interval-based coding system, we measured developmental change in infant posture, how mothers and infants positioned themselves relative to one another, and how they populated interaction spaces with objects. Results showed that mother-infant dyads co-constructed interaction spaces and that the contributions of each partner changed across development. Dyads progressively adopted a broader spatial co-orientation during play (e.g., positioned at right angles) across the first year. Moreover, advances in infants' postural skills, particularly increases in the use of independent sitting in real time, uniquely predicted change in dyadic co-orientation and infants' actions with objects, independent of age. Taken together, we show that the embodied properties of dyadic object play help determine how interactions are physically organized and unfold, both in real time and across the first year of life.

Maternal excess adiposity and serum 25-hydroxyvitamin D < 50 nmol/L are associated with elevated whole body fat mass in healthy breastfed neonates.

BACKGROUND: Vitamin D status of pregnant women is associated with body composition of the offspring. The objective of this study was to assess whether the association between maternal vitamin D status and neonatal adiposity is modified by maternal adiposity preconception. METHODS: Healthy mothers and their term appropriate weight for gestational age (AGA) infants (n = 142; 59% male, Greater Montreal, March 2016-2019) were studied at birth and 1 month postpartum (2-6 weeks). Newborn (24-36 h) serum was collected to measure total 25-hydroxyvitamin D [25(OH)D] (immunoassay); maternal pre-pregnancy BMI was obtained from the medical record. Anthropometry, body composition (dual-energy X-ray absorptiometry) and serum 25(OH)D were measured at 2-6 weeks postpartum in mothers and infants. Mothers were grouped into 4 categories based on their vitamin D status (sufficient 25(OH)D ≥ 50 nmol/L vs. at risk of being insufficient < 50 nmol/L) and pre-pregnancy BMI (< 25 vs. ≥25 kg/m2): insufficient-recommended weight (I-RW, n = 24); insufficient-overweight/obese (I-OW/O, n = 21); sufficient-recommended weight (S-RW, n = 69); and sufficient-overweight/obese (S-OW/O, n = 28). Partial correlation and linear fixed effects model were used while adjusting for covariates. RESULTS: At birth, infant serum 25(OH)D mean concentrations were below 50 nmol/L, the cut-point for sufficiency, for both maternal pre-pregnancy BMI categories; 47.8 [95%CI: 43.8, 51.9] nmol/L if BMI < 25 kg/m2 and 38.1 [95%CI: 33.5, 42.7] nmol/L if BMI ≥25 kg/m2. Infant serum 25(OH)D concentrations at birth (r = 0.77; P < 0.0001) and 1 month (r = 0.59, P < 0.0001) were positively correlated with maternal postpartum serum 25(OH)D concentrations. Maternal serum 25(OH)D concentration was weakly correlated with maternal percent whole body fat mass (r = - 0.26, P = 0.002). Infants of mothers in I-OW/O had higher fat mass versus those of mothers in S-OW/O (914.0 [95%CI: 766.4, 1061.6] vs. 780.7 [95%CI: 659.3, 902.0] g; effect size [Hedges' g: 0.42]; P = 0.04 adjusting for covariates) with magnitude of difference of 220.4 g or ~ 28% difference. CONCLUSIONS: Maternal and neonatal vitamin D status are positively correlated. In this study, maternal adiposity and serum 25(OH)D < 50 nmol/L are dual exposures for neonatal adiposity. These findings reinforce the importance of vitamin D supplementation early in infancy irrespective of vitamin D stores acquired in utero and maternal weight status.

Transacting brains: testing an actor-partner model of frontal EEG activity in mother-infant dyads.

Studies have long observed the bidirectional nature of mother-infant relationships. While behavioral studies have shown that mothers high in social avoidance tendencies can influence the development of these traits in their offspring, the neurophysiological mechanisms underlying this phenomenon, and the role that the infants play, are not well understood. Here we acquired frontal electroencephalogram asymmetry (FA) data simultaneously in 40 mother-infant dyads (Mage mother = 31.6 years; Mage infant = 9 months). Using an actor-partner interdependence model, we examined whether mother (or infant) resting-state FA predicted infant (or mother) FA during two subsequent emotion-eliciting conditions (happy and fear). Maternal social approach versus avoidance traits were assessed as moderators to examine the impact of maternal characteristics on these mother-infant FA relations. In dyads led by mothers with high social avoidance/low social approach characteristics, maternal resting-state FA predicted infant FA during both emotion-eliciting conditions. We did not observe any effects of infant FA on mothers. Therefore, we speculate that individual differences in FA patterns might be a putative brain mechanism through which socially avoidant mothers transfer affective/behavioral information to their infants.

Sensitivity to the communicative partner's attentional state: A developmental study on mother-infant dyads in wild chimpanzees (Pan troglodytes schweinfurthii).

Gestural communication permeates all domains of chimpanzees' social life and is intentional in use. However, we still have only limited information on how young apes develop the sociocognitive skills needed for intentional communication. In this cross-sectional study, we document the development of behavioral adjustment to the recipient's visual attention-considered a hallmark of intentional communication-in wild immature chimpanzees' gestural communication. We studied 11 immature chimpanzees (Pan troglodytes schweinfurthii): three infants, four juveniles, and four adolescents gesturing towards their mother. We quantified silent-visual, audible, and contact gestures indexed to maternal visual attention and inattention. We investigated unimodal adjustment, defined by the capacity of young chimpanzees to deploy fewer silent-visual signals when their mothers did not show full visual attention towards them as compared with when they did. We then examined cross-modal adjustment, defined as the capacity of chimpanzees to deploy more audible-or-contact gestures than silent-visual gestures in the condition where their mothers did not show full visual attention as compared to when they did. Our results show a gradual decline in the use of silent-visual gestures when the mother is not visually attentive with increasing age. The absence of silent-visual gesture production toward a visually inattentive recipient (complete unimodal adjustment) was not fully in place until adolescence. Immature chimpanzees used more audible-or-contact gestures than silent-visual ones when their mothers did not show visual attention and vice-versa when they did. This cross-modal adjustment was expressed in juveniles and adolescents but not in infants. Overall, this study shows that infant chimpanzees were limited in their sensitivity to maternal attention when gesturing, whereas adolescent chimpanzees adjusted their communication appropriately. Juveniles present an intermediate pattern with cross-modal adjustment preceding unimodal adjustment and with variability in the age of onset.

Attention-sensitive signalling by 7- to 20-month-old infants in a comparative perspective.

Attention-sensitive signalling is the pragmatic skill of signallers who adjust the modality of their communicative signals to their recipient's attention state. This study provides the first comprehensive evidence for its onset and development in 7-to 20-month-olds human infants, and underlines its significance for language acquisition and evolutionary history. Mother-infant dyads (N = 30) were studied in naturalistic settings, sampled according to three developmental periods (in months); [7-10], [11-14], and [15-20]. Infant's signals were classified by dominant perceptible sensory modality and proportions compared according to their mother's visual attention, infant-directed speech and tactile contact. Maternal visual attention and infant-directed speech were influential on the onset and steepness of infants' communicative adjustments. The ability to inhibit silent-visual signals towards visually inattentive mothers (unimodal adjustment) predated the ability to deploy audible-or-contact signals in this case (cross-modal adjustment). Maternal scaffolding of infant's early pragmatic skills through her infant-directed speech operates on the facilitation of infant's unimodal adjustment, the preference for oral over gestural signals, and the audio-visual combinations of signals. Additionally, breakdowns in maternal visual attention are associated with increased use of the audible-oral modality/channel. The evolutionary role of the sharing of attentional resources between parents and infants into the emergence of modern language is discussed.

Investigation of Human Milk as a Biological System in a Multicenter Mother-Infant Cohort: Protocol Design and Cohort Profile of the Phoenix Study.

Breastfeeding and human milk are the gold standard for infant feeding. Studying human milk with a systems biology approach in a large longitudinal cohort is needed to understand its complexity and health implications. The Phoenix study is a multicenter cohort study focusing on the interactions of maternal characteristics, human milk composition, infant feeding practices, and health outcomes of Chinese mothers and infants. A total of 779 mother-infant dyads were recruited from November 2021 to September 2022, and 769 mother-infant dyads were enrolled in the study. Scheduled home visits took place at 1, 4, 6, and 12 months postpartum, and 696 dyads (90.5% participants) completed the 12-month visit. At each visit, maternal and infant anthropometry was assessed. Questionnaires were administered to collect longitudinal information on maternal characteristics and lifestyle, infant feeding, and health. Digital diaries were used to record maternal dietary intake, infant feeding, and stool character. Human milk, maternal feces, infant feces, and infant saliva were collected. An external pharmaceutical-level quality assurance approach was implied to ensure the trial quality. Multi-omics techniques (including glycomics, lipidomics, proteomics, and microbiomics) and machine learning algorithms were integrated into the sample and data analysis. The protocol design of the Phoenix study provides a framework for prospective cohort studies of mother-infant dyads and will provide insights into the complex dynamics of human milk and its interplay with maternal and infant health outcomes in the Chinese population.

Face to face interactions in chimpanzee (Pan troglodytes) and human (Homo sapiens) mother-infant dyads.

Human mothers interact with their infants in different ways. In Western, educated, industrialized, rich and democratic (WEIRD) societies, face-to-face interactions and mutual gazes are especially frequent, yet little is known about their developmental trajectories and if they differ from those of other primates. Using a cross-species developmental approach, we compared mother-infant interactions in 10 dyads of urban humans from a WEIRD society (Homo sapiens) and 10 dyads of captive zoo-based chimpanzees (Pan troglodytes), when infants were one, six and 12 months old. Results showed that face-to-face interactions with mutual gaze events were common in both groups throughout the infant's first year of life. The developmental trajectories of maternal and infants' looks partially differed between species, but mutual gaze events were overall longer in humans than in chimpanzees. Mutual gazes were also more frequent in humans, peaking at six months in humans, while increasing with age in chimpanzees. The duration and frequency of mutual gazes varied across contexts in both groups, with mutual gazes being longer during caring/grooming and feeding contexts. These findings confirm that some aspects of early socio-cognitive development are shared by humans and other primates, and highlight the importance of combining developmental and cross-species approaches to better understand the evolutionary roots of parenting behaviour. This article is part of a discussion meeting issue 'Face2face: advancing the science of social interaction'.

Relationships reduce risks for child maltreatment: Results of an experimental trial of Infant Mental Health Home Visiting.

Background: Research examining the effectiveness of home visiting programs that reduce child maltreatment or associated risks yield mixed findings; some find positive significant impacts on maltreatment, whereas others find small to no effects. The Michigan Model of Infant Mental Health Home Visiting (IMH-HV) is a manualized, needs-driven, relationship-focused, home-based intervention service that significantly impacts maternal and child outcomes; the effect of this intervention on child maltreatment has not been sufficiently evaluated. Objective: The current study examined associations between treatment and dosage of IMH-HV and child abuse potential in a longitudinal, randomized controlled trial (RCT). Participants and setting: Participants included 66 mother-infant dyads (Mother M age = 31.93 years at baseline; child M age = 11.22 months at baseline) who received up to 1 year of IMH-HV treatment (Mdn = 32 visits) or no IMH-HV treatment during the study period. Methods: Mothers completed a battery of assessments including the Brief Child Abuse Potential Inventory (BCAP) at baseline and at the 12-month follow-up assessment. Results: Regression analyses indicated that after controlling for baseline BCAP scores, those who received any IMH-HV treatment had lower 12-month BCAP scores compared to those who received no treatment. Additionally, participation in more visits was associated with lower child abuse potential at 12 months, and a reduced likelihood of scoring in the risk range. Conclusion: Findings suggest that greater participation in IMH-HV is associated with decreased risk for child maltreatment 1 year after initiating treatment. IMH-HV promotes parent-clinician therapeutic alliance and provides infant-parent psychotherapy which differentiate it from traditional home visiting programs.

The role of mother-infant emotional synchrony in speech processing in 9-month-old infants.

Rhythmicity characterizes both interpersonal synchrony and spoken language. Emotions and language are forms of interpersonal communication, which interact with each other throughout development. We investigated whether and how emotional synchrony between mothers and their 9-month-old infants relates to infants' word segmentation as an early marker of language development. Twenty-six 9-month-old infants and their German-speaking mothers took part in the study. To measure emotional synchrony, we coded positive, neutral and negative emotional expressions of the mothers and their infants during a free play session. We then calculated the degree to which the mothers' and their infants' matching emotional expressions followed a predictable pattern. To measure word segmentation, we familiarized infants with auditory text passages and tested how long they looked at the screen while listening to familiar versus novel words. We found that higher levels of predictability (i.e. low entropy) during mother-infant interaction is associated with infants' word segmentation performance. These findings suggest that individual differences in word segmentation relate to the complexity and predictability of emotional expressions during mother-infant interactions.

Association and Occurrence of Bifidobacterial Phylotypes Between Breast Milk and Fecal Microbiomes in Mother-Infant Dyads During the First 2 Years of Life.

Breast milk acts as an intermediary for the transfer of functionally important commensal bacteria from mother to infant, especially for Bifidobacterium that can colonize the infant gut. However, the vast majority of rRNA amplicon-based studies reported the conspicuous intercohort and interindividual variation for the prevalence of Bifidobacterium in breast milk. In order to elucidate whether Bifidobacterium phylotypes persistently co-occured at the species or strain level in mother-breast milk-infant triads, we analyzed collectively the next-generation sequencing (NGS) datasets of bacterial 16S rRNA gene and the Bifidobacterium-specific groEL gene from maternal feces, breast milk, and infant feces in a small yet very homogeneous cohort of 25 healthy Uyghur mother-infant pairs (lactation for 7-720 days) in Kashgar, Xinjiang, China. Overall, 16S rRNA gene analysis showed that microbiome in the newborn gut was closer to that of breast milk in the first 4 months of lactation, and subsequently showed an obvious trend of adulthood at 6-12 months. Based on the BLAST accurate taxonomic result of the representative sequences of all ASVs (amplicon sequencing variants), only three sets of ASVs could be clearly assigned into Bifidobacterium species, whereas the remaining eight sets of ASVs corresponded to four indefinite Bifidobacterium species group. By contrast, the groEL gene dataset was partitioned into 376 ASVs, at least belonging to 13 well-known Bifidobacterium species or subspecies, of which 15 ASVs, annotated to seven well-known Bifidobacterium species or subspecies, showed triadic synchronism in most 23 mother-infant pairs tested. However, several other rare bifidobacterial phylotypes, which were frequently encountered in animals, were found to display no correspondence of the presence between the three ecosystems of mother-infant pairs. Our test results were obviously to support the hypothesis that breast milk acts as an intermediary for the transfer of probiotic commensal bacteria from mother to infant, especially for endosymbiotic Bifidobacterium that can colonize the infant gut. Some oxygen-insensitive exogenous Bifidobacterium phylotypes with a cosmopolitan lifestyle may be indirectly transferred to breast milk and the infant's intestinal tract through environmental contamination. Thus, the groEL gene proved to be a very effective target for the depth resolution of Bifidobacterium community by high-throughput sequencing technologies.

Exploring Factors Linked to Weight Status in Salvadoran Infants.

INTRODUCTION: Potential risk factors of infant overweight/obesity in Salvadoran mother-infant dyads (N = 88) at routine 9- to 12-month wellbaby visits were examined in a correlational study at two pediatric offices on Long Island, New York. METHOD: Maternal factors and infant feeding practices in the first 5 months were self-reported; infant birth weight, current weight/recumbent length were obtained. Bivariate logistic regression measured the relationship of the variables with infant weight status >85th percentile weight-for-length (WFL) for sex. RESULTS: The majority of mothers were born in El Salvador, with a mean age of 28.5 years (SD = 5.9); 43% of infants had WFL >85th percentile. Infant birth weight was significantly associated with WFL >85th percentile, p = .0007. After controlling for maternal age, insurance type, education, and marital status, no significant associations with infant WFL >85th percentile were found. Feeding practices during infants' first 5 months, mothers' pre-pregnancy weight, pregnancy weight gain, and history of gestational diabetes mellitus, were not associated with infant weight status. CONCLUSION: This was the first study to examine infant weight status in Salvadorans. Future studies should objectively measure infant feeding practices and other potential factors among Salvadoran mother infant dyads, since nearly half of the infants had WFL >85th percentile.

Factors associated with prelacteal feeding practices in Debre Berhan district, North Shoa, Central Ethiopia: a cross-sectional, community-based study.

BACKGROUND: Prelacteal feeding is one of the major harmful newborn feeding practices and is top on the list of global public health concerns. The practice deprives newborns of valuable nutrients and protection of colostrum and exposes them to preventable morbidity and mortality. Studying the prevalence and factors influencing the prelacteal feeding practice of mothers will help program managers and implementers to properly address broad major public health problems. Therefore, this study aims to investigate the prevalence of prelacteal feeding practices and its associated factors among mother-infant dyads in the Debre Berhan district of North Shoa administrative zone, central Ethiopia. METHODS: A community-based cross-sectional study design was conducted from January through to April 2014 among 634 mother-infant dyads. The data were entered into EPI Info version 3.5.1. (CDC, Atlanta, Georgia). All statistical analysis was conducted using Statistical Package for Social Sciences (SPSS) research IBM version 20.0. The prevalence of prelacteal feeding was determined using the 'recall since birth' method. Multi-variable logistic regression analysis was employed to control confounders in determining the association between prelacteal feeding practices and selected independent variables. Adjusted Odds Ratio (AOR), with 95% Confidence Interval (CI) and P < 0.05 was used to claim statistical significance. RESULTS: The prevalence of prelacteal feeding practice was 14.2% (95% CI: 11.00-17.00%). Slightly greater than half, 48 (53.3%) of prelacteal fed newborns were given butter. Home delivery was a major risk factor for practicing prelacteal feeding. Mothers who delivered their indexed infant at home practiced prelacteal feeding over four folds more than mothers who delivered in a health institution (Adjusted Odds Ratio (AOR) 4.70; 95% CI: 2.56-8.60, p-value = 0.001). Mothers who did not initiate breastfeeding within an hour were six times more likely to practice prelacteal feeding (AOR 5.58; 3.21-9.46, p-value = 0.001). Similarly, with regards to the occupation of mothers, farmers practiced prelacteal feedings (AOR 4.33; 95% CI: 1.73-10.81, p-value = 0.002) up to four folds more than their counterpart housewives. Mothers who can read and write are 54% less likely to practice prelacteal feeding than their counterpart, illiterate mothers, with (AOR 0.46; 95% CI: 0.22-0.98, p-value = 0.044). CONCLUSIONS: In the Debre Berhan town of North Shoa administrative zone, central Ethiopia, almost one-sixth of mothers practiced prelacteal feeding. Therefore, improving access to information about appropriate newborn feeding practices, encouraging mothers to deliver their babies in health institutions and inspiring them to initiate breastfeeding within an hour of birth is recommended.

The effect of mother-infant skin-to-skin contact on Ghanaian infants' response to the Still Face Task: Comparison between Ghanaian and Canadian mother-infant dyads.

The effect of mother-infant skin-to-skin contact on Ghanaian infants' developing social expectations for maternal behavior was investigated. Infants with high and low mother-infant skin-to-skin contact experience in the infants' first month engaged with their mothers in a Still Face Task at 6 weeks of age. Infants with high skin-to-skin contact experience, but not those with low skin-to-skin contact experience, demonstrated the still face effect with their smiles. Infants with both high and low skin-to-skin contact experience demonstrated the still face effect with their visual attention. The behaviors of the Ghanaian infants and their mothers during the task were compared to archival evidence of Canadian mother-infant dyads' behaviors in skin-to-skin and control groups who engaged in the Still Face Task at the infant ages of 1 and 2 months. Similarities and differences between the behaviors of the mother-infant dyads in the two cultures were assessed.

Learning to like vegetables during breastfeeding: a randomized clinical trial of lactating mothers and infants.

Background: What lactating mothers eat flavors breast milk and, in turn, modifies their infants' acceptance of similarly flavored foods.Objective: We sought to determine the effects of the timing and duration of eating a variety of vegetables during breastfeeding on the liking of vegetables in both members of the dyad.Design: We conducted a randomized controlled study of 97 mother-infant dyads. Lactating mothers drank vegetable, beet, celery, and carrot juices for 1 mo beginning at 0.5, 1.5, or 2.5 mo postpartum or for 3 mo beginning at 0.5 mo postpartum. The control group drank equal volumes of water and avoided drinking the juices. Mothers rated the tastes of the juices and self-reported dietary intakes at each monthly visit (0.5-4.5 mo). After weaning, when 7.9 mo of age, infants' acceptance of plain, carrot-flavor (exposed flavor), and broccoli-flavor (nonexposed flavor) cereals was assessed on separate days.Results: The timing of exposure affected the acceptance of the carrot flavor that did not generalize to the novel broccoli flavor. A relatively brief experience (1 mo) with vegetable flavors in mothers' milk, starting at 0.5 mo postpartum, was sufficient to shift the hedonic tone, which resulted in a faster rate of eating carrot-flavored cereal than that in infants who were exposed during subsequent months or not at all. One month of exposure had a greater effect than 3 mo of exposure or no exposure. Regardless of when exposure occurred, infants were less likely to display facial expressions of distaste initially when eating the carrot cereal. Over time, mothers liked the tastes of carrot, beet, and celery juices more, but no changes in dietary intake of vegetables were observed.Conclusions: Early life may be an optimum time for both infants and their mothers to learn to like the taste of healthy foods. More research is needed to facilitate the liking and eating of these foods by mothers, which will, in turn, increase the likelihood of their feeding these foods to their children. This trial was registered at clinicaltrials.gov as NCT01667549.

A análise da fala materna dirigida a bebês em duas etapas do desenvolvimento / Analyses of maternal speech to babies in two steps of the development

A linguagem é considerada um instrumento de mediação simbólica que caracteriza a espécie humana e é fundamental nas trocas interpessoais e na internalização dos processos constituídos nessas trocas. Neste artigo foram descritas contribuições teóricas acerca do desenvolvimento da linguagem, e o papel da fala do adulto nesse processo. O modelo de Roman Jackobson foi adotado para análise de características pragmáticas da fala materna. Foram transcritas e analisadas as falas maternas em 40 díades, em dois momentos do desenvolvimento do bebê (30 dias e 5 meses). Foram ainda analisados os aspectos afetivos e cognitivos dessa linguagem. Os resultados mostraram uma predominância da função fática em ambas as faixas etárias. Houve também predominância dos aspectos afetivos em relação aos cognitivos. Acredita-se que o conhecimento das características da fala materna em etapas iniciais do desenvolvimento e a identificação dos aspectos pragmáticos, que podem colaborar para o desenvolvimento da linguagem infantil, são de especial relevância.

Language is considered an instrument of symbolic mediation that characterizes the human species, involved in interpersonal exchanges and internalization of the processes that are constructed in these exchanges. In this article the theoretical contributions and conceptions about language development were described, and the role of adults’ speech in this process. Roman Jackobson’s model of was adopted for the analyses of pragmatic characteristics of mothers’ speech. Mothers’ talk of 40 dyads were transcribed and analyzed in two moments of the babies’ development (30 days and 5 months). The affective and cognitive aspects of maternal language were also analyzed. The results indicated the predominance of phatic function in both age groups. Affective aspects were also more frequent in relation to cognitive ones. Knowledge about maternal and child language characteristics at the initial stages of development, and the identification of its pragmatic aspects that can contribute for child language development are relevant.