Childhood psychological maltreatment and social anxiety in college students: The roles of parasympathetic nervous system activity and parent-child separation experience.

BACKGROUND: Childhood psychological maltreatment is a risk factor for social anxiety in adulthood. Parent-child separation, as one of the most serious adversities in early life, may exacerbate the risk of psychological maltreatment and influence the interactions between childhood psychological maltreatment and biological sensitivity to stress in relation to social anxiety. However, there has been a dearth of work on this issue. OBJECTIVE: This study investigated the interactive effects between childhood psychological maltreatment and parasympathetic nervous system (PNS) activity on social anxiety in college students by comparing those who experienced parent-child separation versus those who did not. Potential sex differences in the aforementioned associations were tested as an exploratory aim. PARTICIPANTS AND SETTING: Data were obtained from 264 college students (Mage = 18.45 years, SD = 0.69), including 156 students who experienced parent-child separation and 108 students without this experience. METHODS: Participants completed measures of childhood psychological maltreatment and social anxiety and reported their parent-child separation experience. The data of PNS activity, measured by respiratory sinus arrhythmia (RSA) reactivity, were obtained during the Trier Social Stress Test (TSST) in the lab. RESULTS: Childhood psychological maltreatment was positively associated with college students' social anxiety. RSA reactivity moderated the relationship between childhood psychological maltreatment and college students' social anxiety, and the moderating role of RSA reactivity varied with parent-child separation experience and sex. CONCLUSIONS: Parent-child separation experience influenced the biosocial interactions between childhood psychological maltreatment and PNS activity in relation to individuals' social anxiety, and this effect persisted in adulthood.

Age-dependent associations between RSA reactivity, affective and cognitive regulation, and psychopathology risk in young children exposed to varying levels of socioeconomic disadvantage.

This study examined autonomic nervous system activity (respiratory sinus arrhythmia [RSA]) as a biomarker of psychopathology in an ethnically and socioeconomically diverse sample (N = 57) of young children ages 4-7 years. RSA was measured at baseline and across four standardized tasks designed to assess self-regulation in both affective (i.e., "hot") and cognitive (i.e., "cool") contexts during early childhood. Our findings reveal that age moderated RSA activity, such that reduced RSA suppression was associated with a heightened risk of externalizing problems among older children during "cool" and "hot" contexts; for younger children, only RSA suppression during "hot" contexts predicted externalizing risk. The influence of socioeconomic disadvantage did not moderate the relationship between RSA and the risk of psychopathology, and there were minimal associations between RSA suppression and internalizing symptoms at this age range. These results suggest that autonomic variability may be a more effective predictor of psychopathology risk in older children, perhaps as they transition into formal schooling and face increasingly complex cognitive and social demands. Findings have implications for the identification of psychopathology in early developmental periods when regulation over emotions becomes essential for academic and social success.

Resting respiratory sinus arrhythmia moderates the within-person relations of parental emotional expressivity and children's prosocial behaviors.

Parental supportive emotional expressivity could contribute to children's prosocial behaviors, and such an effect may differ for children with different levels of resting respiratory sinus arrhythmia (RSA). This study disentangled the stable differences across dyads (i.e., between-person effects) from the dynamic associations between parental expressivity and children's prosocial behaviors within dyads (i.e., within-person effects) and determined how resting RSA functioned as a susceptibility factor in such effects. The longitudinal design consisted of three measurements with a 1-year interval performed among 208 school-aged children (48.6% girls; Han nationality) and their parents (153 mothers and 55 fathers). The initial measurement was conducted when the children were 7 years old (Mage  = 7.13, SDage  = .33). Resting RSA was calculated at the first measurement; parents reported children's prosocial behaviors and parental expressivity at each of the three measurements. The results demonstrated significant between- and within-person effects of parental expressivity on children's prosocial behaviors and found a moderating role of children's resting RSA in the within-person effects. These findings suggest that children displayed more prosocial behaviors when parents showed more supportive expressivity both across and within dyads, and higher resting RSA operated as a differential susceptibility factor in the intraindividual fluctuations in parental expressivity.

Weakened sympathetic response and lower parasympathetic activity in intimate partner violence perpetrators when empathizing: Influence of autonomous activation in affective approach and prosocial behavior.

The autonomic nervous system (ANS) functioning has been proposed as a relevant method to characterize the therapeutic needs of intimate partner violence (IPV) perpetrators. Nevertheless, research has neglected the influence of the ANS on socio-affective functions in this population. The aim of the present study was to analyze the psychophysiological activity of IPV perpetrators (n = 52) compared to controls (n = 46) following an empathic induction task, performed through negative emotion-eliciting videos. We employed two general ANS markers (heart rate [HR] and respiratory rate [RR]), two sympathetic-related indexes (pre-ejection period [PEP] and skin conductance level [SCL]) and a parasympathetic biomarker (respiratory sinus arrhythmia [RSA]). Additionally, we explored the impact of psychophysiological activity on prosocial behavior using Hare's donation procedure. Compared to controls, IPV perpetrators reported lower HR and SCL following the task, as well as longer PEP, suggesting an attenuated sympathetic response to others' distress. No differences in the RSA response pattern were found, however, IPV perpetrators displayed lower overall RSA levels throughout the protocol, indicative of reduced parasympathetic activity. Besides, while no differences in prosocial performance were observed, greater sympathetic responses and overall parasympathetic activity predicted increased donations across the sample. Thus, a high sympathetic and parasympathetic activity might influence the occurrence of prosocial behavior. The present study provides further evidence supporting that IPV perpetrators cope differently with others' negative emotions. In line with this biopsychosocial perspective, insights are gained on the emotional processing of IPV perpetrators which, in turn, could contribute to improve IPV psychotherapeutic programs.

The role of mother's and child's self-regulation on bidirectional links between harsh parenting and child externalizing problems.

The authors examined task-based (i.e., executive function), surveyed (i.e., effortful control), and physiological (i.e., resting cardiac respiratory sinus arrhythmia [RSA]) measures of child and maternal regulation as distinct moderators of longitudinal bidirectional links between child externalizing (EXT) behaviors and harsh parenting (HP) from 6 to 9 years. The sample size was 299 (50.9% female; 1% Asian, 4% multiple races; 14% Black; 78% White), and participants were recruited in the United States (a rural college town in Virginia and a midsized city in North Carolina). Higher child EXT at 6 years predicted higher HP at 7-8 years, which predicted higher EXT at 9 years. Also, this path was moderated by 6-year child effortful control, 6-year resting RSA, and 9-year executive function. In contrast, there was no moderating effect of any measure of maternal regulation. Findings suggest it is important to consider child self-regulation when examining bidirectionality in parent and child effects for HP and child EXT. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Patterns of respiratory sinus arrhythmia and trajectories of anxiety and depressive symptoms in early adolescence.

In children and adults, individual differences in patterns of respiratory sinus arrhythmia (RSA; i.e., interactions between resting RSA and RSA reactivity to stress) have emerged as a central predictor of internalizing symptoms. However, it is unclear whether individual differences in patterns of RSA also contribute to internalizing symptoms during the key developmental period of early adolescence, when rates of internalizing symptoms sharply increase. In the present multi-wave longitudinal study, we assessed whether patterns of RSA predicted trajectories of the two most common types of internalizing symptoms among adolescents: anxiety and depression. In the baseline session, we assessed RSA at rest and in response to a psychosocial stressor (Trier Social Stress Test [TSST]) in a sample of 75 early adolescents (Mage = 12.85). Youth then completed measures of anxiety and depressive symptoms at baseline and four times over approximately two years. Findings indicate that RSA patterns predicted trajectories of anxiety, but not depression. Specifically, region of significance analyses indicated that individuals with high resting RSA who demonstrated RSA augmentation to the lab stressor evinced decreasing anxiety over the follow-up period. In direct contrast, adolescents with high resting RSA in combination with RSA withdrawal to the stressor exhibited a trajectory of increasing anxiety. Findings provide preliminary evidence for understanding RSA as a developmentally salient risk or protective factor.

Nonlinear Moderation Effect of Vagal Regulation on the Link between Childhood Trauma and Adolescent Internalizing and Externalizing Symptoms.

Childhood trauma is a leading early adverse environment that increases psychopathological symptoms. Respiratory sinus arrhythmia (RSA) suppression to challenges as a marker of self-regulation is found to linearly moderate the link between early adverse experiences and psychopathological symptoms, but yielding mixed findings. The present study examined the relationships between childhood trauma and internalizing and externalizing symptoms via a 1.5-year longitudinal design and the quadratic moderation effect of RSA suppression on these relationships among adolescents. In November 2021 (T1), the final sample of 275 Chinese adolescents (Mage = 12.94, SDage = 0.79; 49.82% females) completed the short form of Childhood Trauma Questionnaire and the Achenbach Youth Self-Report-2001 and underwent a speech task during which their baseline RSA and stress exposure RSA were obtained. In June 2023 (T2), 251 adolescents completed the Achenbach Youth Self-Report-2001. Results showed that childhood trauma at T1 was positively correlated with internalizing and externalizing symptoms at T1 and T2. RSA suppression to stress quadratically moderated these associations, such that adolescents with moderate rather than higher or lower RSA suppression had the least internalizing and externalizing symptoms at T1 and T2 when exposed to childhood trauma. The findings suggest that moderate RSA suppression to stress as a marker of optimal vagal regulation buffers the risk of developmental psychopathology from early adverse experiences.

PEP reward reactivity moderates the effects of RSA reactivity on antisocial behavior and substance use.

Integrating Polyvagal Theory and Reinforcement Sensitivity Theory (RST), we examined pre-ejection period (PEP) reward reactivity, which was suggested to index trait impulsivity, as a moderator between respiratory sinus arrhythmia (RSA) reactivity and antisocial behavior (ASB), and substance use in an urban male, adult sample. To understand the inconsistent findings between RSA reactivity and externalizing problems, we proposed to study both negatively and positively valenced tasks for RSA reactivity and to include PEP reward reactivity as a moderator for the RSA-behavior link. Data were collected from an urban sample of 131 male adults (active offenders, demographic controls, and college students). ICG (impedance cardiography) and ECG (electrocardiogram) were recorded, computing PEP (sympathetic nervous system activity marker) and RSA (parasympathetic nervous system activity marker), while participants completed the modified Trier Social Stress Test and a simple reward task. Reactivity was calculated by subtracting the baseline from the task activity. Consistent with prior studies, more RSA withdrawal to stress and less PEP shortening to reward predicted the most ASB and substance use. Less RSA withdrawal to reward and more PEP shortening to reward predicted the most ASB and substance use. We incorporated autonomic space, RST, and Polyvagal Theory to discuss our findings, and specifically highlight how clarifying what each reactivity captures based on the task demand (e.g., presence of social threat, need for vagal-mediated social affiliative behavior) can illuminate our understanding of the result patterns.

Self- and co-regulation of physiological activity during mother-daughter interactions: The role of adolescent non-suicidal self-injury.

BACKGROUND: Non-suicidal self-injury (NSSI) is a significant public health concern that is thought to increase risk for future self-injurious behaviors, including suicide attempts. Notably, NSSI is especially prevalent among adolescents, which underscores a critical need to identify modifiable risk factors that could be targeted to reduce future risk. The current study examined self- and co-regulation of physiological responses during mother-daughter interactions in adolescent girls with and without a history of NSSI. METHODS: Participants were 60 girls aged 13-17 with (n = 27) and without (n = 33) a history of NSSI and their mothers. Adolescents and their mothers completed positive and negative interaction tasks during which physiological reactivity was assessed via respiratory sinus arrhythmia (RSA). RESULTS: Using Actor-Partner Interdependence Modeling (APIM), we found that adolescents with an NSSI history demonstrated a higher RSA setpoint than adolescents without this history during the negative, but not positive, interaction task. In addition, there were differences in co-regulation during the negatively valenced interaction, such that mothers of daughters with NSSI were more reactive to fluctuations in their daughters' RSA than mothers of daughters without an NSSI history. CONCLUSIONS: These findings highlight intra- and interpersonal aspects of physiological dysregulation associated with NSSI that could provide promising targets of intervention to reduce future risk in adolescent girls.

Respiratory sinus arrhythmia (RSA) dynamics matter for children's emotion regulation: RSA inertia and instability within a stress task.

The present study employed two key dynamic indicators (i.e., inertia and instability) to the psychophysiological research of child emotion regulation (ER) and examined whether respiratory sinus arrhythmia (RSA) dynamics were associated with child ER during a stress task. Eighty-nine Chinese school-age children (Mage = 8.77 years, SD = 1.80 years; 46.1% girls) and their primary caregivers participated in the study. After controlling for RSA static reactivity, multiple regression analyses indicated that lower RSA inertia was related to fewer in-task negative emotions rated by children and their caregivers, and higher RSA instability was associated with better child trait ER. This study introduces physiological indicators of the dynamic aspects of parasympathetic activity to the study of child ER.

Putting back respiration into respiratory sinus arrhythmia or high-frequency heart rate variability: Implications for interpretation, respiratory rhythmicity, and health.

Research on respiratory sinus arrhythmia, or high-frequency heart rate variability (its frequency-domain equivalent), has been popular in psychology and the behavioral sciences for some time. It is typically interpreted as an indicator of cardiac vagal activity. However, as research has shown for decades, the respiratory pattern can influence the amplitude of these noninvasive measures substantially, without necessarily reflecting changes in tonic cardiac vagal activity. Although changes in respiration are systematically associated with experiential and behavioral states, this potential confound in the interpretation of RSA, or HF-HRV, is rarely considered. Interpretations of within-individual changes in these parameters are therefore only conclusive if undertaken relative to the breathing pattern. The interpretation of absolute levels of these parameters between individuals is additionally burdened with the problem of residual inspiratory cardiac vagal activity in humans. Furthermore, multiple demographic, anthropometric, life-style, health, and medication variables can act as relevant third variables that might explain associations of RSA or HF-HRV with experiential and behavioral variables. Because vagal activity measured by these parameters only represents the portion of cardiac vagal outflow that is modulated by the respiratory rhythm, alternative interpretations beyond cardiac vagal activity should be considered. Accumulating research shows that activity of multiple populations of neurons in the brain and the periphery, and with that organ activity and function, are modulated rhythmically by respiratory activity. Thus, observable health benefits ascribed to the cardiac vagal system through RSA or HF-HRV may actually reflect beneficial effects of respiratory modulation. Respiratory rhythmicity may ultimately provide the mechanism that integrates central, autonomic, and visceral activities.

Cardiac psychophysiological tuning to socioaffective content is disrupted in aged rhesus monkeys (Macaca mulatta).

Aging ushers in numerous disruptions to autonomic nervous system (ANS) function. Although the effects of aging on ANS function at rest are well characterized, there is surprising variation in reports of age-related differences in ANS reactivity to psychosocial stressors, with some reports of decreases and other reports of increases in reactivity with age. The sources of variation in age-related differences are largely unknown. Nonhuman primate models of socioaffective aging may help to uncover sources of this variation as nonhuman primates share key features of human ANS structure and function and researchers have precise control over the environments in which they age. In this report, we assess how response patterns to dynamic socioaffective stimuli in the parasympathetic and sympathetic branches of rhesus monkeys (Macaca mulatta) ANS differ in aged compared to middle-aged monkeys. We find that respiratory sinus arrhythmia, a cardiac indicator of activity in the parasympathetic branch of the ANS, exhibits age-related disruptions in responding while monkeys view videos of conspecifics. This suggests that there are evolutionarily conserved mechanisms responsible for the patterns of affective aging observed in humans and that aged rhesus monkeys are a robust translational model for human affective aging.

Emotion dysregulation and reward responsiveness as predictors of autonomic reactivity to an infant cry task among substance-using pregnant and postpartum women.

Maternal substance use may interfere with optimal parenting, lowering maternal responsiveness during interactions with their children. Previous work has identified maternal autonomic nervous system (ANS) reactivity to parenting-relevant stressors as a promising indicator of real-world parenting behaviors. However, less is known about the extent to which individual differences in emotion dysregulation and reward processing, two mechanisms of substance use, relate to maternal ANS reactivity in substance-using populations. The current study examined associations among emotion dysregulation, reward responsiveness, and ANS reactivity to an infant cry task among 77 low-income and substance-using women who were either pregnant (n = 63) or postpartum (n = 14). Two indicators of ANS functioning were collected during a 9 min computerized infant cry task (Crybaby task): respiratory sinus arrhythmia (RSA) and pre-ejection period. Mothers also completed self-reported measures of emotion dysregulation and reward responsiveness. Analyses revealed that trait emotion regulation was associated with RSA reactivity to the Crybaby task, such that greater emotion dysregulation was associated with greater RSA reduction during the infant cry task than lower emotion dysregulation. Reward responsiveness was not significantly associated with either indicator of ANS reactivity to the task. Findings revealed distinct patterns of associations linking emotion dysregulation with ANS reactivity during a parenting-related computerized task, suggesting that emotion regulation may be a key intervention target for substance-using mothers.

Acute stress reduces attentional blindness: Relations with resting respiratory sinus arrhythmia and cortisol.

This study made the first attempt to combine resting respiratory sinus arrhythmia (RSA) and cortisol to provide an explanatory mechanism for the effect of acute stress on emotion-induced blindness (EIB) from the perspective of vagus nerve activity and stress hormone responses. For this purpose, resting electrocardiogram (ECG) signals were recorded first. Participants underwent both the socially evaluated cold-pressor test and control treatments 7 days apart and then completed the EIB task. Heart rate and saliva samples were collected over time. The results demonstrated that acute stress promoted the overall detection of targets. Resting RSA and cortisol levels predicted the stress-induced changes in EIB performance under the negative distractor condition at lag2 negatively and positively, respectively. These findings indicate that the effect of stress on EIB was partially contributed by cortisol, which is more relevant to negative distractor conditions. Resting RSA, as an indicator of inter-individual differences, further provided evidence from the perspective of the trait emotional regulation ability based on the vagus nerve control. In general, resting RSA and cortisol changes over time exhibit different patterns of influence on stress-induced changes in EIB performance. Thus, this study provides a more comprehensive understanding of the effect of acute stress on attentional blindness.

Respiratory sinus arrhythmia (RSA), vagal tone and biobehavioral integration: Beyond parasympathetic function.

Linchpin to the entire area of psychophysiological research and discussion of the vagus is the respiratory and cardiovascular phenomenon known as respiratory sinus arrhythmia (RSA; often synonymous with high-frequency heart-rate variability when it is specifically linked to respiratory frequency), i.e. rhythmic fluctuations in heart rate synchronized to inspiration and expiration. This article aims 1) to clarify concepts, terms and measures commonly employed during the last half century in the scientific literature, which relate vagal function to psychological processes and general aspects of health; and 2) to expand upon an earlier theoretical model, emphasizing the importance of RSA well beyond the current focus upon parasympathetic mechanisms. A close examination of RSA and its relations to the vagus may 1) dispel certain commonly held beliefs about associations between psychological functioning, RSA and the parasympathetic nervous system (for which the vagus nerve plays a major role), and 2) offer fresh perspectives about the likely functions and adaptive significance of RSA, as well as RSA's relationship to vagal control. RSA is neither an invariably reliable index of cardiac vagal tone nor of central vagal outflow to the heart. The model here presented posits that RSA represents an evolutionarily entrenched, cardiovascular and respiratory phenomenon that significantly contributes to meeting continuously changing metabolic, energy and behavioral demands.

Respiratory sinus arrhythmia in spontaneously breathing, unanesthetized newborn and adult Wistar rats.

We examined respiratory sinus arrhythmia (RSA) and possible interaction with respiratory frequency (fR) and heart rate (HR) in spontaneously breathing, unanesthetized newborn Wistar rats (2- to 5-day-old; n = 54) and the adult rats (8-week-old; n = 34). Instantaneous heart rate (inst-HR) was calculated as the reciprocal of the inter-beat-interval. For each breath, RSA was determined as the difference between the maximum and minimum inst-HR value. The absolute RSA or RSA% (RSA per HR) were calculated as the average RSA of 10 consecutive breaths. RSA (or RSA%) in the newborn rats was significantly lower than that in the adult rats. Correlation coefficient between RSA (or RSA%) and 1/fR or HR/fR, but not HR, was significant in newborn rats, whereas only that between RSA (or RSA%) and HR was significant in adult rats. The power spectrum density of heartbeat fluctuation was detectable in both age groups. The present findings suggest that RSA exists and could be influenced by fR, rather than HR, in newborn rats.

Long-term stability of respiratory sinus arrhythmia among adults with and without a history of depression.

Respiratory sinus arrhythmia (RSA) is an index of parasympathetic nervous system activity reflecting respiratory influences on heart rate. This influence is typically measured as high frequency heart rate variability (HF-HRV) or root mean square of successive differences (RMSSD) of adjacent inter-beat intervals. Examining the long-term stability of its measurement is important as levels of resting RSA have been conceptualized as a marker of individual differences; in particular, of an individual's autonomic regulation and affect-related processes, including emotion regulation. At present, it is not known if resting RSA levels reflect stable differences over a long-term period (i.e., >1 year). Even less is known about how RSA stability differs as a function of depression history and whether it relates to depression risk trajectories. In the present study, we examined the 1.5-year test-retest reliability of resting RSA using the intraclass correlation coefficient (ICC) in 82 adults: n = 41 with a history of depression (ever-depressed); n = 41 controls with no depression history (never-depressed). HF-HRV was fairly stable in both groups (ever-depressed ICC = 0.55, never-depressed ICC = 0.54). RMSSD was also fairly stable in ever-depressed adults (ICC = 0.57) and never-depressed controls (ICC = 0.40). ICC values for both indices did not differ between groups per overlapping 95% confidence intervals. Therefore, RSA stability as assessed by both frequency (HF-HRV) and time domain (RMSSD) measures was not attenuated by a depression history. Implications and the need for future research are discussed.

Childhood trauma, intraindividual reaction time variability, baseline respiratory sinus arrhythmia, and perceived relapse tendency among males with substance use disorders.

Background: People with substance use disorders (SUDs) who have experienced serious childhood trauma may have executive function impairments contributing to relapse. Baseline respiratory sinus arrhythmia (RSA) reflects physiological regulation capacity, which has been found to buffer the negative effects of childhood trauma. Baseline RSA has also been found to be related to intraindividual reaction time variability (IIRTV), which is an index of executive function.Objectives: The present study examined the relationship between childhood trauma and perceived relapse tendency, the mediation role of IIRTV, and the moderation role of baseline RSA.Methods: The study is cross-sectional, a total of 110 males with SUDs participated (Mage = 46.45 years, SD = 11.24). The Childhood Trauma Questionnaire and Intention to Rehabilitate Questionnaire were used to assess childhood trauma and perceived relapse tendency, the two-choice oddball task was used to measure IIRTV, and electrocardiogram (ECG) data were collected to obtain baseline RSA.Results: IIRTV mediated the relationship between childhood trauma and perceived relapse tendency (Coeff = 0.049, Boot CI [0.004, 0.121]); interaction of childhood trauma and Baseline RSA negatively influences IIRTV (ß = -0.208, t = -2.022, p = .046).Conclusion: The results suggest that males with SUDs who have experienced serious childhood trauma may have executive function impairments that contribute to relapse, and baseline RSA may buffer the negative effect of childhood trauma on IIRTV. These findings suggest that the prevention of relapse through cognitive enhancement can be complemented by the enhancement of physiological regulation.

Spontaneous infant crying modulates vagal activity in real time.

Porges' polyvagal theory (1991) proposes that the activity of the vagal nerve modulates moment-by-moment changes in adaptive behavior during stress. However, most work, including research with infants, has only examined vagal changes at low temporal resolutions, averaging 30+ s across phases of structured stressor paradigms. Thus, the true timescale of vagal regulation-and the extent to which it can be observed during unprompted crying-is unknown. The current study utilized a recently validated method to calculate respiratory sinus arrhythmia (RSA) dynamically at a high resolution of 5 Hz (updated every 200 ms) in a home-based infant study. Using an event-related analysis, we calculated the relative change in RSA around the onset of naturally occurring unprompted instances of n = 41 infants' 180 crying events. As predicted, RSA significantly decreased after the onset of crying compared to non-crying chance changes in RSA. Decreasing trends in RSA were driven by infants with higher pre-cry RSA values, infants rated lower in Negative Affectivity, and those rated both high and low in Orienting by their mothers. Our results display the timescale of RSA in spontaneous and naturalistic episodes of infant crying and that these dynamic RSA patterns are aligned with real-time levels of RSA and also caregiver-reported temperament.

Concurrent and lagged physiological synchrony during mother-child interaction and their relationship to positive affect in 8- to 10-year-old children.

Mother-child interaction has been characterized by a fine-tuning of behavior and physiological activity. Yet, little is known about the dynamics of mother-child physiological synchrony during early school age and their associations to positive affect. To investigate these processes, 42 mother-child dyads, with children aged 8 to 10 years, played an interactive game while their interbeat intervals (IBI) and respiratory sinus arrhythmia (RSA) were measured simultaneously. IBI/RSA synchrony was calculated using cross-correlations of the IBI/RSA second-by-second time series for lags - 3 to + 3 seconds. Mother's and child's individual and shared positive affect were microcoded. During the interactive tasks, IBI and RSA synchrony significantly increased compared to control conditions. RSA and affect synchrony were significantly stronger for negative compared to positive lags indicating a stronger child leads/mother follows covariation. Further, dyad's IBI and RSA synchrony were significantly associated to mother's and child's individual positive affect. Our data suggest that in low-risk community samples, mothers may respond to their children's positive affect by matching their own affect and physiology. Investigating these temporally precise, concurrent and lagged synchrony processes may open up new avenues for understanding the ways in which parent-child interactions contribute to child developmental outcomes.