Mother-Infant Cardiac Synchrony is Related to Word Segmentation at 9 Months of Age

• In Event: Word segmentation and statistical learning

Abstract

Neonatal biological pacemakers, such as heart rate variability and sleep-wake cyclicity, are linked to infant’s capacity to partake in early communication and to the emergence of parent-infant interpersonal synchrony (Feldman, 2006). Interpersonal synchrony, that is the temporal alignment of behaviors and biological rhythms, influences different aspects of child’s social development, such as attachment and self-regulation (Feldman, 2007).

One crucial aspect of infant’s social development is language. Both interpersonal synchrony and language development grow within social interactions. Rhythmicity characterizes both early interactions and spoken language. For example, mother-infant interactions are characterized by regular and recurring cycles of behavior. Moreover, infants use their sensitivity to the rhythmic organization of phonemes, syllables and words to segment speech. Despite the commonalities, to our knowledge, the link between parent-infant synchrony and language development remains unexplored.

Earlier, the first evidence was found on the link between mother-infant behavioral synchrony, namely the matching of emotional expressions, and infants’ word segmentation, an early marker of language development (Vanoncini et al., 2022). Given the association between behavioral and cardiac synchrony (Feldman et al., 2011), and the fact that foundations of both cardiac synchrony and language development lie in rhythm, we next investigated the relationship between cardiac synchrony and language development.

Respiratory sinus arrhythmia (RSA) is a biomarker of parent-child cardiac synchrony (Nguyen et al., 2021). Here, we examined whether mother-infant cardiac synchrony, measured by mother and infant RSA reactivity, is related to early word segmentation at 9 months of age. We hypothesized that higher levels of mother-infant cardiac synchrony will be associated with higher word segmentation performance.

Data of 29 9-month-old infants and their German-speaking mothers were included in the analyses. All dyads performed 5 minutes of free play while their cardiac activity was measured using dual-electrocardiogram. With an eye-tracking-based central fixation paradigm, we tested infants’ word segmentation. We familiarized infants with auditory text passages in German containing two target words (i.e., familiarized words). At test, infants were presented with familiarized words and novel words. Word segmentation was defined as the difference of looking times (LTs) to familiarized versus novel words divided by the total LTs at test (i.e., preference score).

For statistical analysis, we used state RSA, which is defined as the fluctuations of mother’s and infant’s RSA from their own average RSA (Fuchs et al., 2021). A mixed model examined the RSA fluctuations in relation to word segmentation. More specifically, we tested infant’s state RSA as a function of mother’s state RSA and preference score. Dyad was included as random effect.

Results revealed that mother-to-infant RSA fluctuations was moderated by the preference score: the higher the association between cardiac signals of mothers and their infants were, the more infants tended to look towards novel trials indicating a mature word segmentation performance (p < 0.001). This indicates that mother-infant cardiac synchrony is associated with an advanced word segmentation performance. Our study shows for the first time that physiological coupling between mothers and their infants not only shapes self-regulation and attachment, but also higher-level functions such as language.

Authors

• Monica Vanoncini, University of Potsdam
  Presenting Author

• Natalie Boll-Avetisyan, University of Potsdam

• Birgit Elsner, University of Potsdam

• Stefanie Hoehl, University of Vienna

• Ezgi Kayhan, University of Potsdam