Respiratory sinus arrhythmia and prosociality in childhood: Evidence for a quadratic effect

Moderate cardiac vagal tone is associated with more cooperation in children

Childhood is a crucial period for prosocial development, including cooperative behaviors. Recent studies have shown a quadratic relation (inverted U-shape curve) between cardiac vagal tone (CVT) and various prosocial emotions and behaviors in children, but data are lacking on cooperative behaviors. In a sample of 111 school-aged children (M = 7.77; SD = 1.24, range: 6-11), we tested the association between the root mean square of successive differences in interbeat intervals (RMSSD) at rest, and cooperative behavior in a task designed to be comparable to a stag hunt game. We found evidence for an association between RMSSD and cooperation that follows an inverted U-shape. In addition, older children were more likely to cooperate than younger children. Lastly, we found an interaction between RMSSD and age such that the association between RMSSD and cooperation behavior was present for younger but not older children. In addition, we proposed an extension of the Johnson-Neyman test to assess the significant region of interaction between age and the linear and quadratic RMSSD. These results add to a growing literature suggesting that moderate RMSSD is associated with greater prosocial behavior and provide novel evidence that this association extends to children's cooperation.

Encouraging a Peer in Need: The Impacts of Social Anxiety and Peer Familiarity

Extant research has produced conflicting findings regarding the link between social fearfulness and prosocial behavior, with some studies reporting negative relations and others reporting null effects. Furthermore, these studies have focused predominantly on toddlerhood, and few have examined prosociality between peers. The present study investigated whether the link between social anxiety and a prosocial behavior (i.e., providing encouragement) varied depending on interpersonal and situational factors (i.e., one's familiarity with a peer, the level of support sought by a peer, respectively). We tested this question using a multimethod approach, which included an ecologically valid stress inducing task and dyadic design with a sample of 9- to 10-year-olds (N = 447). Results revealed that social anxiety was related negatively to providing encouragement among familiar and unfamiliar dyads. In familiar dyads, however, this main effect was qualified by an interaction with the level of support sought by one's peer. Compared to those low in social anxiety, children high in social anxiety provided relatively less encouragement in response to higher levels of support seeking from their peers. The findings are considered in relation to theorizing regarding the effect of overarousal on children's prosocial behavior.

Autonomic Arousal, Ethical Guilt, and Externalizing Behavior in Childhood: A Clinical Extension and Replication

Lower autonomic arousal is associated with higher externalizing behavior in childhood but the mechanisms explaining this link are still debated. One possibility is that lower autonomic arousal makes it difficult for children to anticipate or express social emotions, such as ethical guilt rooted in concern for others, thereby increasing their likelihood of externalizing behavior. However, evidence for this social-emotional hypothesis has been limited to community samples. The present study included ethnically diverse samples of 150 typically developing children (M_age = 8.01 years; 50% girls) and 62 children referred for clinically elevated externalizing behavior (M_age = 9.16 years; 16% girls; N = 212). Caregivers reported children's externalizing behavior. Children's respiratory sinus arrhythmia (RSA) was measured as an indicator of parasympathetic activity in response to hypothetical vignettes depicting externalizing behavior. Children's ethical guilt was coded from semi-structured interviews following each vignette. Greater RSA increases (indicating a low-arousal, rest-and-digest response) were associated with lower ethical guilt. Lower ethical guilt was associated with higher externalizing behavior. A significant indirect effect showed that RSA increases were associated with higher externalizing behavior through relative lapses in ethical guilt. Results were consistent across and within the community and clinical samples. Theoretical and practical implications for clinically elevated externalizing behavior are discussed.

Parental warmth predicts more child pro-social behaviour in children with better emotion regulation

Parental warmth and child emotion regulation have each been implicated in the development of child pro-social behaviours; however, their interactive benefits remain unclear. In this multi-method, multi-cohort longitudinal study, we examined the effect of parental warmth on child pro-social behaviours at different levels of child emotion regulation. We collected data from 6- and 10-year-olds in Canada (N_T1  = 233; M_age  = 8.41; SD = 2.08) and their parents. Parental warmth, child emotion regulation, and child pro-social behaviours were assessed via parent report. Children's baseline respiratory sinus arrhythmia (RSA; an indicator of cardiac regulatory capacity) was assessed as a correlate of emotion regulation. Child pro-social behaviours were assessed concurrently and 1 year later. Results showed that higher parental warmth was related to higher concurrent prosocial behaviours and greater increases in prosocial behaviours over 1 year. These effects were strengthened for children with higher emotion regulation whether measured by parent report or RSA. We discuss implications for understanding pro-social development in middle childhood from a strengths-based perspective.

Rhythmic Skeletal Muscle Tension Increases Heart Rate Variability at 1 and 6 Contractions Per Minute

Breathing at the resonance frequency (~ 6 breaths per min) produces resonance effects on baroreflex gain, blood pressure, vascular tone, and therapeutic benefits. Evgeny Vaschillo and Paul Lehrer have emphasized that the stimulation frequency is critical for producing resonance effects in the cardiorespiratory system. Although clinicians overwhelmingly use paced breathing to increase HRV, other promising methods exist. Vaschillo, Lehrer, and colleagues have shown that presenting non-respiratory stimulation at 0.1 Hz-pictures with an emotional valence or rhythmical muscle tensing-amplifies oscillations in heart rate, blood pressure, and vascular tone. Participants in the present study included 49 undergraduate students randomly assigned to one of six different orders of 5-min trials of 1, 6, and 12 muscle contractions per min (cpm), separated by 3-min buffer periods intended to minimize carryover. This randomized controlled trial replicated the Vaschillo et al. (Psychophysiology 48:927-936, 2011. https://doi.org/10.1111/j.1469-8986.2010.01156.x ) finding that 6-cpm RSMT can produce a PkFreq of ~ 0.10 Hz, similar to 6-bpm RF breathing. RSMT at 1 and 6 cpm increased five time-domain metrics (HR Max-HR Min, RMSSD, SDNN, TI, and TINN), one frequency-domain metric (LF power), and three non-linear metrics (D2, SD1, SD2) significantly more than RSMT at 12 cpm. There were no differences between 1 and 6 cpm on these measures. The 1-cpm rate (~ 0.02 Hz) may have stimulated the hypothesized vascular tone baroreflex between 0.02 and 0.055 Hz. RSMT at 1 or 6 cpm provides clients with an alternative exercise for increasing HRV for patients who find slow-paced breathing challenging or medically unsafe.

Association Between Dynamic Parasympathetic Reactivity to Frustration and Children's Social Success with Peers in Kindergarten

The inability to regulate affective arousal in the context of frustration may jeopardize children's ability to form successful friendships, especially as new peer groups are formed during the transition to kindergarten. While substantial research has utilized teacher reports of children's socioemotional behavior, there is less empirical evidence on the peer perspective. The present study utilized data from n = 235 kindergarteners (54% high in disruptive behavior) recruited for a multicomponent intervention. We examined whether physiological reactivity to frustration was associated with children's social success. Peer nominations of liking or disliking to play with the child were used to compute a social preference score, where negative values reflect greater rejection than acceptance. Multilevel growth modeling was employed to capture changes in respiratory sinus arrhythmia (RSA) reactivity across a manipulated inhibitory control task administered in 3 blocks, with differing algorithms embedded to induce affect: points were earned in the 1st and 3rd blocks (reward) and lost during the 2nd block (frustration). Groups did not differ in RSA reactivity during the 1st block, but children who experience greater peer rejection showed significant decreases in RSA (increases in arousal) across frustration. This increased arousal persisted across the 3rd block despite the reinstatement of reward, indicating a greater degree of reactivity and a lack of recovery relative to peer-accepted children. Teacher screenings of disruptive behavior only partially aligned with peer ratings of acceptance, highlighting the benefits of leveraging peer report to capture regulatory functioning and identify children for intervention recruitment.

The Development of Generosity From 4 to 6 Years: Examining Stability and the Biopsychosocial Contributions of Children's Vagal Flexibility and Mothers' Compassion

Individual differences in children’s prosocial behaviors, including their willingness to give up something of value for the benefit of others, are rooted in physiological and environmental processes. In a sample of 4-year-old children, we previously found evidence that flexible changes in respiratory sinus arrhythmia (RSA) were linked to donation behavior, and that these physiological patterns may support greater sensitivity to the positive effects of compassionate parenting on donation behavior. The current study focused on a follow-up assessment of these children at age 6. First, we examined the stability of individual differences in donation behavior and related parasympathetic nervous system (PNS) activity from age 4 to 6. Second, we examined associations between donation behavior and RSA at 6 years. Third, we examined whether the association between children’s RSA and donation behavior at age 6 varied depending on mothers’ compassionate love. We found low to modest stability in donation behavior and RSA reactivity from age 4 to 6. These findings provide preliminary evidence that stable individual differences in altruism, as reflected by generosity, and in some aspects of parasympathetic functioning during opportunities to be prosocial, emerge in childhood. In addition, we found that some of the same associations between donation behavior, RSA, and compassionate love that we previously observed in children at 4 years of age continued to be evident 2 years later at age 6. Greater decreases in RSA when given the opportunity to donate were associated with children donating more of their own resources which, in turn, were associated with greater RSA recovery after the task. Lastly, mothers’ compassionate love was positively associated with donation behavior in children who demonstrated stronger decreases in RSA during the task; compassionate parenting and RSA reactivity may serve as external and internal supports for prosociality that build on each other. Taken together, these findings contribute to the perspectives that individual differences in altruistic behaviors are intrinsically linked to healthy vagal flexibility, and that biopsychosocial approaches provide a useful framework for examining and understanding the environmental and physiological processes underlying these individual differences.

Getting to the heart of childhood empathy: Relations with shyness and respiratory sinus arrhythmia

Although prior studies have found that shyness and empathy are inversely related and that well-regulated children tend to express empathic behaviors more often, little work has assessed combinations of these factors in predicting affective and cognitive empathy in early childhood. The authors examined relations among shyness, resting respiratory sinus arrhythmia (RSA), and observed affective and cognitive empathy in a sample of 130 typically developing children (M_age  = 63.5 months, SD = 12.2; 62 males). Shyness was assessed by observing children's behaviors during a self-presentation task, and this observed measure was then combined with a maternal report of children's temperamental shyness. Children's shyness predicted lower levels of both affective and cognitive responses to an experimenter feigning an injury. Resting RSA moderated the relation between children's shyness and observed empathy such that relatively higher shyness combined with lower RSA levels conferred the lowest levels of cognitive empathy. Children who were relatively low in shyness exhibited similar levels of cognitive empathy across different levels of RSA. However, this moderation was not found when predicting children's affective empathy. Our results suggest that not all shy children are alike in terms of their empathic behaviors: shy children who are physiologically dysregulated appear to have difficulties exploring and/or processing others' pain.