Differential Effects of Infant Vocalizations on Approach-Avoidance Postural Movements in Mothers

Co-regulation, relationship quality, and infant distress vocalizations observed during mother-infant interactions: Influences of maternal depression and different contexts

Mother-infant interactions are co-regulated and provide the foundation for mother-infant relationship quality. The implications of maternal depression and contextual demands (i.e., reinstating the interaction following maternal unavailability and vocalized infant distress) on observationally coded co-regulation in mother-infant dyads (n = 40) at 4-months was investigated. Associations among co-regulation patterns and mother-infant relationship quality was also examined. Dyads participated in Still-Face (SF) and Separation (SP) procedures, with periods of maternal emotional and physical unavailability. Co-regulation was captured using the Revised Relational Coding System. Relationship quality was examined using the Emotional Availability Scales. Dyads in the depressed group had significantly more unilateral exchanges than the non-depressed group following the SF and SP perturbations. The depressed group also had significantly more distress vocalizations during the SP perturbation than the non-depressed group. Co-regulation in the depressed group was less disrupted by the SF perturbation. Positive relationship quality dimensions (maternal sensitivity, structuring, and infant responsiveness) were associated with more symmetrical and less unilateral co-regulation regardless of the interaction period. There were also context-specific results pertaining to patterns of co-regulation and associated maternal hostility and infant responsiveness. Results highlight co-regulatory differences in depressed mothers and their infants and how these differences are exacerbated by contextual demands.

Breastfeeding at Any Cost? Adverse Effects of Breastfeeding Pain on Mother-Infant Behavior

Breast milk is considered the ideal infant nutrition, and medical organizations encourage breastfeeding worldwide. Moreover, breastfeeding is often perceived as a natural and spontaneous socio-biological process and one of the fundamental roles of new mothers. While breastfeeding is beneficial, little scientific consideration has been given to its potential psychological challenges. Here, we investigate the phenomenon of breastfeeding pain in mothers and its association with maternal and infant behavioral regulation. During the postpartum weeks, the mother-infant dyad can be considered one allostatic unit directed at infant regulation and development. We hypothesize that pain comprises an allostatic challenge for mothers and will thus impair the capacity for dyadic regulation. To test this, we recruited 71 mothers with varying levels of breastfeeding pain and videotaped them with their infants (2-35 weeks old) during spontaneous face-to-face interactions. We quantified the individual differences in dyadic regulation by behaviorally coding the second-by-second affective expressions for each mother and infant throughout their interactions. We tested the extent to which breastfeeding pain alters affect regulation during mother-infant interactions. We discovered that mothers with severe breastfeeding pain express less affective expressions and less infant-directed gaze during interactive moments of engagement and play than mothers with no or moderate pain. Moreover, infants of mothers experiencing pain during breastfeeding express less affective expressions and more mother-directed gaze while interacting with their mothers than infants of mothers who are not in pain. This demonstrates that the allostatic challenge of maternal pain interferes with the behavioral regulation of both mothers and infants. Since the mother-infant dyad is a codependent allostatic unit, the allostatic challenges of one partner can impact the dyad and thus potentially impact child development, bonding, and mother and infant well-being. The challenges of breastfeeding should be considered in addition to the nutritional advances.

Approach-avoidance behavioural patterns towards an affective voice

Facial expressions are evolutionarily acquired social signals that are processed rapidly by the receiver when deciding to either approach or avoid the person sending the signal. The predominance of the approach or avoidance responses has been examined for various facial expressions. Similar to facial expressions, the approach-avoidance response to affective voice may have been acquired evolutionarily. However, studies examining approach-avoidance to an affective voice are limited. This study used the approach-avoidance task framework developed for facial expressions to determine the dominant behavioural responses to affective voices that indicate either happiness or anger. The results show that the approach response was dominant for the happy voice, while the avoidance response was dominant for the angry voice. This tendency was observed even without the presence of any facial stimuli. These results suggest that an affective voice may be an evolutionarily acquired approach-avoidance-inducing social signal, similar to facial expressions.

Approach-Avoidance Behavior in the Empathy for Pain Model as Measured by Posturography

The interrelation between motor and emotional processes has been a recurrent question since several decades in the scientific literature. An interesting experimental technique to explore this question is posturography which assess the modulation of human postural control. In an emerging scientific field, this technique has been used to explore the reaction of the body in different emotional conditions. However, among available studies, some inconsistencies appear. In this brief report, we want to show how a widely used experimental model, i.e., empathy for pain, allowed in several study to provide comprehensive understanding elements on the postural correlates of socioemotional information processing. In particular, the role of mental simulation is discussed.

High plasticity in marmoset monkey vocal development from infancy to adulthood

The vocal behavior of human infants undergoes marked changes across their first year while becoming increasingly speech-like. Conversely, vocal development in nonhuman primates has been assumed to be largely predetermined and completed within the first postnatal months. Contradicting this assumption, we found a dichotomy between the development of call features and vocal sequences in marmoset monkeys, suggestive of a role for experience. While changes in call features were related to physical maturation, sequences of and transitions between calls remained flexible until adulthood. As in humans, marmoset vocal behavior developed in stages correlated with motor and social development stages. These findings are evidence for a prolonged phase of plasticity during marmoset vocal development, a crucial primate evolutionary preadaptation for the emergence of vocal learning and speech.

Postural correlates of painful stimuli exposure: impact of mental simulation processes and pain-level of the stimuli

Previous studies have reported (i) freezing-like posturographic correlates in response to painful as compared to non-painful scenes vision (Lelard et al., Front Hum Neurosci 7:4, 2013) and (ii) an increase of this response during the mental simulation as compared to the passive viewing of the painful scenes (Lelard et al., Front Psychol 8:2012, 2017). The main objective of the present study was to explore the modulation of posturographic correlates of painful scenes vision by the level of depicted pain and the influence of mental simulation on this modulation. Thirty-six participants (36.3 ± 11.4 years old) were included in this study. During the experiment, participants had to stand on a posturographic platform. Three types of static visual stimuli were randomly depicting different pain-level situations: no-pain, low-pain, high-pain. In a first run, participants watched these stimuli passively (passive condition); in a second run, they were asked to "imagine that they were personally experiencing the situations they were about to see" (mental simulation condition). For each picture, subjective ratings were recorded for displeasure and desire to avoid at the end of the posturographic session. Results support an approach-type behavior in response to high-pain stimuli in the passive condition which becomes a withdrawal-type behavior in the mental simulation condition. Moreover, this withdrawal-type behavior is modulated by the level of depicted pain and this modulation does not appear for the subjective data. As a conclusion, these results are in accordance with those of previous studies showing the modulation of posturographic correlates of pain perception by mental simulation and report, for the first time, modulation of this effect by the level of depicted pain. The dichotomy of this modulatory effect between subjective and objective data is discussed as well as the finding of an approach-type behavior towards painful stimuli when passively viewing them becoming a withdrawal-type behavior when mental simulation is applied to the same stimuli.

The influence of cognitive load on maternal postural sway and heart rate in response to infant vocalizations

Infants communicate their emotions to their caregivers through cries and laughter. Recent work suggests that adaptive parenting requires cognitive regulation of intuitive behaviors toward infants' signals. In this study, we examined the effects of cognitive regulation on mothers' unconscious behavioral and cardiac responses to infant cries and laughs. In all, 55 mothers took part in this study. To manipulate cognitive load, mothers were asked to memorize alphabet characters (two letters in the low cognitive load condition and eight in the high cognitive load condition). Then, they heard infant vocalizations (cries or laughs) for 6 s. During this time, we measured mothers' behavioral (center of pressure, an index of approach-avoidance behavior) and physiological (heart rate) responses. Regardless of vocalization type (infant cries or laughs), high cognitive load increased mothers' forward movement toward the infant sounds as well as mothers' heart rate. These findings advance our understanding of the link between executive function and maternal response to infant signals by utilizing postural and physiological measures of maternal response during memory tasks that require cognitive resources.