Acute stress reactivity from contested dominance in dominant and submissive males

Validity of mental and physical stress models

Different stress models are employed to enhance our understanding of the underlying mechanisms and explore potential interventions. However, the utility of these models remains a critical concern, as their validities may be limited by the complexity of stress processes. Literature review revealed that both mental and physical stress models possess reasonable construct and criterion validities, respectively reflected in psychometrically assessed stress ratings and in activation of the sympathoadrenal system and the hypothalamic-pituitary-adrenal axis. The findings are less robust, though, in the pharmacological perturbations' domain, including such agents as adenosine or dobutamine. Likewise, stress models' convergent- and discriminant validity vary depending on the stressors' nature. Stress models share similarities, but also have important differences regarding their validities. Specific traits defined by the nature of the stressor stimulus should be taken into consideration when selecting stress models. Doing so can personalize prevention and treatment of stress-related antecedents, its acute processing, and chronic sequelae. Further work is warranted to refine stress models' validity and customize them so they commensurate diverse populations and circumstances.

Induced Social Power Improves Visual Working Memory

The possibility that social power improves working memory relative to conditions of powerlessness has been invoked to explain why manipulations of power improve performance in many cognitive tasks. Yet, whether power facilitates working memory performance has never been tested directly. In three studies, we induced high or low sense of power using the episodic recall task and tested participants' visual working memory capacity. We found that working memory capacity estimates were higher in the high-power than in the low-power condition in the standard change-detection task (Study 1), in a variation of the task that introduced distractors alongside the targets (Study 2), and in a variation that used real-world objects (Study 3). Studies 2 and 3 also tested whether high power improved working memory relative to low power by enhancing filtering efficiency, but did not find support for this hypothesis. We discuss implications for theories of both power and working memory.

Endocrine differences among colour morphs in a lizard with alternative behavioural strategies

Alternative behavioural strategies of colour morphs are expected to associate with endocrine differences and to correspond to differences in physical performance (e.g. movement speed, bite force in lizards); yet the nature of correlated physiological and performance traits in colour polymorphic species varies widely. Colour morphs of male tawny dragon lizards Ctenophorus decresii have previously been found to differ in aggressive and anti-predator behaviours. We tested whether known behavioural differences correspond to differences in circulating baseline and post-capture stress levels of androgen and corticosterone, as well as bite force (an indicator of aggressive performance) and field body temperature. Immediately after capture, the aggressive orange morph had higher circulating androgen than the grey morph or the yellow morph. Furthermore, the orange morph maintained high androgen following acute stress (30min of capture); whereas androgen increased in the grey and yellow morphs. This may reflect the previously defined behavioural differences among morphs as the aggressive response of the yellow morph is conditional on the colour of the competitor and the grey morph shows consistently low aggression. In contrast, all morphs showed an increase in corticosterone concentration after capture stress and morphs did not differ in levels of corticosterone stress magnitude (CSM). Morphs did not differ in size- and temperature-corrected bite force but did in body temperature at capture. Differences in circulating androgen and body temperature are consistent with morph-specific behavioural strategies in C. decresii but our results indicate a complex relationship between hormones, behaviour, temperature and bite force within and between colour morphs.

Genetic and Environmental Contributions to Covariation Between DHEA and Testosterone in Adolescent Twins

Although several studies have shown that pubertal tempo and timing are shaped by genetic and environmental factors, few studies consider to what extent endocrine triggers of puberty are shaped by genetic and environmental factors. Doing so moves the field from examining correlated developmentally-sensitive biomarkers toward understanding what drives those associations. Two puberty related hormones, dehydroepiandrosterone and testosterone, were assayed from salivary samples in 118 MZ (62 % female), 111 same sex DZ (46 % female) and 103 opposite-sex DZ twin pairs, aged 12-16 years (M = 13.1, SD = 1.3). Pubertal status was assessed with a composite of mother- and self-reports. We used biometric models to estimate the genetic and environmental influences on the variance and covariance in testosterone and DHEA, with and without controlling for their association with puberty, and to test for sex differences. In males, the variance in testosterone and pubertal status was due to shared and non-shared environmental factors; variation in DHEA was due to genetic and non-shared environmental factors. In females, variance in testosterone was due to genetic and non-shared environmental factors; genetic, shared, and non-shared environmental factors contributed equally to variation in DHEA. In males, the testosterone-DHEA covariance was primarily due to shared environmental factors that overlapped with puberty as well as shared and non-shared environmental covariation specific to testosterone and DHEA. In females, the testosterone-DHEA covariance was due to genetic factors overlapping with pubertal status, and shared and non-shared environmental covariation specific to testosterone and DHEA.

Social stratification, health, and violence in the very young

Inequalities in human social groups contribute in important ways to the initiation and perpetuation of violence. Because both social inequalities and interpersonal aggression emerge in early life, it is important to study their developmental origins in the collective and individual behavior of young children. As young as 2 years of age, children assemble stable, linearly transitive dominance hierarchies when brought together in novel social groups. Just as the consequences of socioeconomic status may be due in part to experiences of social ordering per se, subjective childhood experiences of occupying a lesser or greater position on a scale of social influence may similarly affect health, safety, and behavior in early development. Children's experiences with social ordering may represent a first, formative encounter with the hierarchical social relations that affect health and susceptibility to violence over the human lifespan. We have studied the health correlates of group stressors, dominance positions, and biobehavioral reactivity within cohorts of preschool children and semi free-ranging rhesus macaques. Social position is ascertained using naturalistic observations of critical dyadic events, and stress-reactivity is measured using assessments of behavioral and biological responses to standardized challenges. Outcome measures, including indicators of mental and physical health and interpersonal injuries, have been assessed--in the case of children--with parent- and teacher-report questionnaires, child self-report protocols, and frequent, objective physical examinations of the child and--in the case of rhesus monkeys--with daily observations of violence-related injuries. Results to date have suggested the following provisional conclusions: (1) Children and monkeys form stable, linearly transitive social hierarchies in which identifiable subgroups of individuals occupy dominant and subordinate social positions. (2) Individuals occupying subordinate positions within the social group show exaggerated adrenocortical and/or autonomic reactivity to challenge and disproportionate rates of chronic medical conditions or violent injuries. (3) Stress-reactivity, naturally occurring stressors, and social position are interactively predictive of rates of morbidity. Monkeys who displayed high biobehavioral reactivity sustained disproportionate numbers of violent injuries during a confinement stressor. Children who were high in the dominance hierarchy and low in reactivity showed significantly higher rates of externalizing mental health symptoms, while those who were in subordinate social positions and high in reactivity showed higher prevalences of internalizing symptoms. In conclusion, the prevention of youth violence--and other forms of early disorder--will require a deeper, developmental understanding of the "headwaters" of aggression and victimization in early childhood and a stronger accounting of how early social inequalities set trajectories toward healthy or disordered behavior.

Cardiovascular functioning, personality, and the social world: the domain of hierarchical power

The present paper considers connections between cardiovascular functioning (i.e., disease status and acute stress responses) and social dominance, and its counterpart, social submissiveness, both of which are part of the broader domain of "hierarchical power" [Bugental, D.B., 2000. Acquisition of the algorithms of social life: a domain-based approach. Psychological Bulletin 126, 187-219]. Empirical research on connections between dominance/submissiveness and cardiovascular morbidity and mortality in humans is reviewed, as is research on dominance/submissiveness and cardiovascular reactivity to, and recovery from, acute stressors. Three general conclusions are established. First, in both cross-sectional and longitudinal investigations, trait and behavioral indicators of dominance have been positively associated with cardiovascular disease severity, incidence, and progression, whereas preliminary evidence from two studies suggests that trait submissiveness may protect against poorer disease outcomes. Second, among men and women, trait dominance is associated with reactivity to and recovery from acute stressors, particularly social challenges. Third, linkages between dominance/submissiveness and cardiovascular functioning, especially cardiovascular reactivity, are characterized by gender-specific patterning, and this patterning emerges as a function of social context. Implications for the next generation of research concerning social dominance, gender, and cardiovascular functioning are discussed.

Applying mixed regression models to the analysis of repeated-measures data in psychosomatic medicine

OBJECTIVE

Although repeated-measures designs are increasingly common in research on psychosomatic medicine, they are not well suited to the conventional statistical techniques that scientists often apply to them. The goal of this article is to introduce readers to mixed regression models, which provide a more flexible and accurate framework for managing repeated-measures data.

METHODS AND RESULTS

We begin with a summary of the advantages that mixed regression models have over conventional statistical techniques in the context of repeated-measures designs. Next, we outline the conceptual and mathematical underpinnings of mixed regression models for a nonstatistical audience. The article ends with two examples of how these models can be applied in psychosomatic research; one deals with a prospective investigation of depressive symptoms and change in body mass index in older adults and the other with a diary study of social interactions and cortisol secretion.

CONCLUSIONS

Mixed regression models offer a flexible and powerful approach to analyzing repeated-measures data. They possess important advantages over more traditional strategies, and more widespread application of these models is likely to enhance the overall quality of psychosomatic research.

Effects of social anxiety and evaluative threat on cardiovascular responses to active performance situations

This study investigated the joint influence of trait social anxiety and evaluative threat on psychological and cardiovascular responses to active coping situations. Fifty-two normotensive female students characterized as either high or low in trait social anxiety performed a mental arithmetic task and a speech task requiring persuasive behavior in a context of high or low evaluative threat. Trait social anxiety exerted a substantial influence on cardiovascular reactivity. High socially anxious individuals overall exhibited greater heart rate reactivity. For systolic and diastolic blood pressure enhanced reactivity of socially anxious individuals was confined to low evaluative threat. At high levels of evaluative threat no group differences were observed due to somewhat attenuated reactivity in high compared to low socially anxious individuals. Cognitive appraisals and affective arousal were not found to mediate the effects of social anxiety on cardiovascular reactivity. Results were attributed to differences in effort expenditure rather than experienced anxiety.

Cardiovascular reactivity during dyadic social interaction: The roles of gender and dominance

The present study examined relationships among gender, trait dominance, and cardiovascular reactivity assessed during dyadic social interactions between same-gender and same-ethnicity participants. One-hundred sixty dyads, 76 comprised of African American participants and 84 comprised of European American participants, engaged in three 4-min discussions while their heart rate and blood pressure responses were assessed. All dyads were composed of unacquainted partners. Multilevel modeling for dyadic data revealed that trait dominance was significantly and positively associated with blood pressure reactivity during the discussions, but only among men who interacted with a highly dominant partner. The results of the present study add to the weight of the evidence identifying dominance as a social domain of significance for cardiovascular functioning, particularly among men. Potential reasons for gender-specific patterning are considered.

Effects of trait dominance on psychological and cardiovascular responses to social influence attempts: the role of gender and partner dominance

This study investigated the influence of trait dominance on cardiovascular reactivity to and recovery from a dyadic interaction task requiring active social influence attempts. Thirty-six male and 36 female normotensive high-school students characterized as either high or low in trait dominance engaged in a mixed-gender discussion with a high or low dominant partner. Trait dominance substantially influenced cardiovascular reactivity to the interpersonal stressor. High dominant participants displayed higher increases in systolic blood pressure (SBP) and pulse pressure (PP), but lower diastolic elevations than low dominant participants. The difference in diastolic reactivity was particularly pronounced in females. Recovery from stress was influenced by level of partner dominance. Participants interacting with a dominant partner showed delayed diastolic recovery. The observed cardiovascular effects seem to reflect greater task engagement and efficient coping in dominant subjects. Group differences in cognitive task appraisals and affective experiences are consistent with this interpretation. Differences in psychological responding were not found to mediate the relation between trait dominance and cardiovascular responses, however.

Power, approach, and inhibition

This article examines how power influences behavior. Elevated power is associated with increased rewards and freedom and thereby activates approach-related tendencies. Reduced power is associated with increased threat, punishment, and social constraint and thereby activates inhibition-related tendencies. The authors derive predictions from recent theorizing about approach and inhibition and review relevant evidence. Specifically, power is associated with (a) positive affect, (b) attention to rewards, (c) automatic information processing, and (d) disinhibited behavior. In contrast, reduced power is associated with (a) negative affect; (b) attention to threat, punishment, others' interests, and those features of the self that are relevant to others' goals; (c) controlled information processing; and (d) inhibited social behavior. The potential moderators and consequences of these power-related behavioral patterns are discussed.

Social defeat as a stressor in humans

Studies on social defeat in humans, and their similarities with studies on social defeat in animals are reviewed. Studies on social defeat in humans typically are conducted as a branch of social psychology, most often focusing on bullying in schools and in workplaces. Victims of bullying are known to suffer from depression, anxiety, sociophobia, loss of self-esteem, psychosomatic diseases, and other behavioral symptoms. On the other hand, animal studies on social defeat, usually based on the rodent resident--intruder paradigm, present findings related to physiological rather than to behavioral consequences of defeat. The two branches use different terminology, e.g., "dominant" and "subordinate" (animal studies) and "bully" and "victim" (human studies). It is suggested that the two fields could benefit from a mutual exchange in theory and methodology.

Cardiovascular correlates of behavioral dominance and hostility during dyadic interaction

The present study examined cardiovascular correlates of expression of, and exposure to, naturally occurring behavioral dominance and hostility during dyadic social interaction. Unacquainted men and women undergraduates participated in three mixed-gender interactions with the same partner while their blood pressure and heart rate were assessed. Videotaped records of the interactions were coded for behavioral dominance and hostility. Exposure effects were apparent for women's systolic blood pressure and men's heart rate, with significantly greater reactivity shown by participants whose partners exhibited more dominance or hostility, respectively. Also, women's expression of dominance was positively and significantly associated with their heart rate reactivity. In addition to providing further evidence that emotion-related features of the social environment contribute to cardiovascular reactivity, these results illustrate that dominance merits attention as a correlate of cardiac stress reactivity, independent of hostility.

Correlations among salivary testosterone, mood, and selective attention to threat in humans

An experiment was designed to investigate the relation among salivary testosterone, mood, and selective attention to threat. The participant group consisted of 32 nonclinical subjects (16 men and 16 women). Individuals completed the Profile Of Mood States (POMS) and performed a pictorial emotional Stroop task measuring selective attention to angry faces. Anticipating a time lag between testosterone (as measured in saliva) and cognitive emotional behavior, multiple time-coursed saliva samples were taken preceding the assessment of questionnaire and task for every subject. In both sexes, salivary testosterone was significantly related to mood (i.e., anger and tension) and selective attention to angry faces when saliva samples were taken 6 h before questionnaire and task assessment. Research on the relation between testosterone and human behavior might benefit by taking into account time lags between the behavioral manifestations and the continuously changing levels of testosterone.