Vagal Tone, Attachment, and Family Conflict as Predictors of Physiological Reactions to Observed Conflict

1. Vagal Tone, Attachment, and Family Conflict as Predictors of Physiological Reactions to Observed Conflict Nancy Darling, Jessica Greenberg, Rebecca M. Noonan, & Andrew R. Burns Thanks to the many participants who shared their lives with us and to the students in Advanced Methods in Adolescent Development who helped collect data for this project. We would particularly like to thank Al Porterfield and Jan Thornton for their invaluable help and advice. This poster can be downloaded from http://oberlin.edu/faculty/ndarling/lab/ead.htm. Abstract Results Does RSA, attachment & past family conflict predict adolescents’ SAM (α amylase) & HPA (cortisol) response? Regression was used to predict SAM and HPA responses. Results are reported in Table 2 below. • Respiratory Sinus Arrhythmia (RSA) is a measure of vagal tone, the control of resting heart rate by the parasympathetic vagus nerve. • RSA measures the extent to which the resting heart rate fluctuates rhythmically with a person's breathing cycle. Normal hearts display an increase in rate with inhalation, and a decrease with exhalation. A person is said to have high vagal tone when their heart rate varies significantly for each respiratory cycle. • Higher baseline RSA is associated with the ability to allocate attentional and physiological resources efficiently. • Individuals with high RSA exhibit better self-control in times of stress (Porges, 1994). • Attachment assesses stable expectations individuals have about themselves and others that come to organize the encoding, storage, retrieval, and manipulation of information related to affective states and experiences of stress versus security (Mikulincer, 1998). • Attachment security has two dimensions. Anxiety is the extent to which individuals attend to environmental threat and, in interpersonal relationships, abandonment. Avoidance is the extent to which individuals are uncomfortable with emotional closeness ((Diamond & Hicks, 2005). • Secure attachment is associated with low anxiety and low avoidance. • Secure attachment is associated with more effective emotional emotion regulation. • Family Conflict. Past experience in family conflict may cause individuals to react differently to observed conflict with peers. One mechanism through which conflict history may affect emotion regulation is through the attachment system (Diamond et al., 2006), however it may also affect individuals directly through learned behaviors and expectations. • The extent to which individuals have been verbally aggressive towards other family members may indicate past problems with the regulation and expression of negative emotions. • The extent to which individuals have experienced verbal aggression directed towards themselves may also change the way in which they experience observed conflict as a threat. Past experience with high levels of conflict in which the individual could not escape, may increase the perception of threat and activate the HPA axis. Alternatively, prior experience with moderate conflict may decrease the perception of conflict as personally threatening. • Do biological, psychological, and contextual factors predict late adolescents’ physiological responses to observing conflict? • Respiratory sinus arhythmia (vagal tone), attachment, and mother-adolescent verbal aggression were used to predict immediate (GSR & heart rate) and hormonal (cortisol and αamylase) stress responses. • Psychology and contextual variables appear to be better predictors of emotion regulation than biological. • Adolescents who are higher in anxious attachment, who worry about being abandoned, showed increased heart rate and high α amylase response when viewing conflict. Both are signs of SAM activation in response to a perceived immediate threat. • Adolescents who reported low family conflict – those who were seldomly the initiator or target of maternal aggression – showed an increased heart rate and, for maternal aggression – higher SAM activation (α amylase). • Adolescents who were more verbally aggressive towards their mothers showed greater cortisol response (higher HPA activation). Does RSA, attachment & past family conflict predict adolescents’ immediate ECG and GSR response to observed conflict? Hiearchical linear models (HLM) were used to predict between person-differences in mean heart rate and GSR from adolescents’ anxiety and avoidance, their reports of their conflictual verbal behaviors towards their mother, their mothers’ conflictual verbal behaviors towards them, and RSA. Within-person differences in heart rate and GSR were predicted from segment (music, neutral discussion, conflict), with the music segment serving as the baseline comparison. Differences in adolescents’ responses to the segments as a function of attachment, maternal conflict, and RSA were tested using between-level interactions. Results are reported in Table 1 below. • Baseline differences: Adolescents with high baseline RSA (an indicator of good emotion regulation), have lower overall heart rate and skin conductance.. • From Baseline to Neutral:Heart rate drops from baseline as adolescents watch the neutral peer interaction.Heart rate decreases are usually interpreted as a sign of increased attention to novel stimuli. Low vagal tone exaggerates the drop in heart rate drop, while high vagal tone suppresses it. Interestingly, anxiety has a similar effect. High verbally aggression towards mothers also exaggerates the decrease in heart rate. • From Baseline to Conflict: ECG decreases from baseline to conflict. The interactions of variables with time need to be interpreted in light of the actual heart rates. • Anxiety: High anxiety suppresses the normative de-acceleration of heart rate from baseline to conflict. All individuals who experience an increase in heart rate from baseline to conflict are above the mean for anxiety. • Low anxiety individuals experience large decreases in heart rate. • Family Conflict:The heart rates of adolescents who rarely experience verbal aggression within the family tend to increase. Those who often experience verbal aggression tend to decrease. Conclusion Introduction • Cortisol (HPA): • Adolescents who were verbally aggressive towards their mothers reacted more to observed conflict (i.e. showed a greater change in cortisol from baseline over time) than did their peers. • Adolescents whose mothers were verbally aggressive towards them were less reactive to observed conflict. • α Amylase (SAM): • Anxious adolescents reacted more to observed conflict. • Adolescents whose mothers were verbally aggressive towards them were less reactive to observed conflict. • Conflict between peers is a highly stressful but normative experience during adolescence. Adolescents’ ability to regulate emotions in response to internal and external demands is important in helping them attend to threat without being overwhelmed. • The goal of the current project is to examine the extent to which vagal tone (RSA), attachment, and prior conflict experiences within the family predict late adolescents’ ability to regulate their emotions while observing conflict. • How does our body react to stress? • The physiological response to stress depends on the balance of two systems. The sympathetic-adrenal-medullary (SAM) system triggers the body to respond actively to threats with fast, short-lived activation of systems. This quick response is moderated and dampened by the hypothalamus-pituitary-adrenal (HPA) system, which acts through the release of glucocorticoids (Bauer, Quas, & Boyce, 2002). HPA activation is slower in onset and of longer duration, and is typically triggered by less controllable stressors and emotional distress. Individual differences in SAM and HPA activation in response to stress appear as early as age three (Lundberg, 1986) and are related to differences in physiology, personality, emotion regulation, and coping. • Thesympathetic-adrenal-medullary (SAM) systemis responsible for the fast-acting 'fight or flight' component of the stress response. • SAM activation causes release of catecholeamines (epinephrine and norepinephrine) leading to arousal and increased blood pressure and heart rate. • The salivary enzyme α-amylase is used to measure SAM activity. Levels of α-amylase are directly correlated to catecholamine baseline levels and to rises in norepinephrine in stressful circumstances. (Chatterton et al., 1974). • Higher levels of α-amylase are associated with less secure attachment, social problems, and poor stress adaptation. • The hypothalamic pituitary adrenocortical (HPA) axis is the slower acting component of the stress response. • HPA activation is associated with more intense or prolonged emotional stress. • HPA activation stimulates cortisol secretion from the adrenal cortex into the blood stream. • In the short-term, cortisol increases arousal and conversion of short-term to long-term memory, and dampens the body's own stress response (i.e. SAM activation). • In stress-inducing protocols, lower HPA is associated with perceiving ones own moods clearly. Worry prolongs physiological reactions by lengthening the psychological representations of stressful stimuli. • Individual differences in emotion regulation • Individuals differ in the extent to which they react to the same stressor. We examine three potential sources of individual differences: physiological, psychological, and environmental. • The efficiency of regulatory control over emotion is theorized to predict emotional reactivity to daily stressful life events. Specifically, individuals who are able to control and regulate their physiological, emotional, and behavioral responses are be expected to experience less negative emotional arousal in response to a stressor than would those individuals who are less able to regulate their responses (Larsen, Diener, & Emmons, 1986). Findings from studies of adolescents suggest that active and attention-based strategies such as self-distraction and attention shifting are linked with decreases in distress, whereas passive focus on the distressing stimulus is associated with increases in distress (Buss & Goldsmith, 1998). Methods Conclusions Sample and Procedure Forty-three late adolescent college students (M age=18.9, 26 females) were recruited from an Introductory Psychology class to participate in the study. Participants were scheduled either singly or in pairs and were greeted by two undergraduate research assistants. After giving informed consent, participants were fitted with fetrodes on their arm, clavicle, and rib to measure heart rate (ECG) and two electrodes on their non-dominant hand to measure galvanic skin response (GSR). ECG and GSR data were collected using portable UFI Biolog units. Participants were seated in comfortable chairs and asked to (a) listen to calm, repetitive music while watching colors changing on a video screen, (b) view a four minute video of two female roommates in a dorm setting, and (c) complete a series of questionnaires. Stimuli were presented on laptop computers with participants using headphones to minimize distraction. The video was scripted to include two sections: a neutral conversation between the roommates that established their friendly relationship (53 seconds) and (2) an escalating conflict that begins when one roommate asks the other to help clean the room and ends with the initiator of the discussion insulting her roommate, yelling, threatening to destroy her artwork, and storming from the room. To control for diurnal variation in cortisol and α amylase levels, all participants were scheduled for 3:00 PM and completed the procedures prior to 4:15PM. To maximize the reliability of the assays, participants affirmed that they had refrained from nicotine for seven days, alcohol for 12 hours, dairy products for 3 hours, and food for one hour prior to data collection. Measures Anxiety and avoidance were measured using the Experience in Close Relationship questionnaire (Brennan, Clark, & Shaver, 1998). Family conflict was measured using verbal conflict of adolescent towards mother and mother towards adolescent (Conflict in Relationship Scale, Wolfe, Wekerle, Reitzel-Jaffe, & Lefebvre, 1998). Respiratory Sinus Arhythmia (RSA). Heart rate variability was measured while participants listened to calm, neutral music while watching a moving colored pattern on the computer screen. RSA (vagal tone) was calculated using procedures described by Allen (2007). Galvanic Skin Response (GSR) and Heart Rate were measured while participants were listening to music, during the neutral conversation, and during the conflict conversation. Mean GSR and heart rate were calculated for each of the three segments. Data from 10 participants was lost due to equipment failure. SAM and HPA activation were measured using salivary assays of α-amylase and cortisol, respectively. Saliva was collecting using a passive drool protocol at three time points: prior to listening to music, 19 minutes after the onset of the video (15 minutes after the end of the conflict) and 30 minutes after the end of the conflict. Samples were frozen immediately after collection and stored at -40C. Concentrations of cortisol and α-amylase were measured with a spectrophotometer following standard laboratory procedures for Salimetrics kits. Cortisol and α-amylase response to the observed conflict were measured by calculating the area under the curve defined by the three points of measurement. • Physiological reactions to observing conflict were used as markers of emotion regulation. • Decreases in heart rate from baseline to observing conflict were interpreted as a sign of attentional focus. • Increases in heart rate from baseline to observing conflict were interpreted as a sign of emotional distress. • Increases in cortisol were seen as a sign of HPA activation in response to uncontrollable threat or stress. • Increases in αamylase were seen as a sign of SAM activation in response to immediate threat or stress. • Psychology and contextual variables appear to be better predictors of emotion regulation than biological. • Adolescents who are higher in anxious attachment, who worry about being abandoned, showed increased heart rate and high α amylase response when viewing conflict. Both are signs of SAM activation in response to a perceived immediate threat. • Adolescents who reported low family conflict – those who were seldomly the initiator or target of maternal aggression – showed an increased heart rate and, for maternal aggression – higher SAM activation (α amylase). • Adolescents who were more verbally aggressive towards their mothers showed greater cortisol response (higher HPA activation).