Effects of affiliation arousal (hope of closeness) and affiliation stress (fear of rejection) on progesterone and cortisol

Teachers' Heart Rate Variability and Behavioral Reactions in Aggressive Interactions: Teachers Can Downregulate Their Physiological Arousal, and Progesterone Favors Social Integrative Teacher Responses

Aggressive student behavior is considered one of the main risk factors for teacher stress. The present study investigated teachers' physiological and behavioral reactions when facing aggressive student behavior and examined which resources favor adaptive teacher reactions. The sample included 42 teachers. We assessed (a) teacher self-reports (i.e., resources, risk factors, and vital exhaustion) (b) classroom observations, (c) ambulatory assessments of teachers' heart rate and heart rate variability, and (d) teachers' progesterone concentrations in the hair. The present study focused on a subsample of ten teachers (9 females, Mage = 34.70, SD = 11.32) managing classes which were potentially very stressful as they had a high density of aggressive behavior. High levels of work satisfaction, hair progesterone, and a low level of work overload fostered social integrative teacher responses. Moreover, in 75% of the cases, teachers succeeded in downregulating their physiological reaction. Our results support the notion that teachers evaluate stressors in light of their resources. When they perceive their resources as insufficient for coping with a challenging situation, stress arises, and subsequently, they react inefficiently to aggressive behavior. Thus, teacher education could benefit from strengthening teacher resources and strategies for coping with aggressive student behavior.

Ovarian hormones predict cooperative strategies updating during multiple rounds of the prisoner's dilemma

Increasing research has focused on how ovarian hormones influence individual prosocial motivation and cooperation. However, most results remain ambiguous and contradictory. Here, we collected progesterone (PROG) and oestradiol from 62 healthy women with regular menstrual cycles to explore whether variations in ovarian hormones could flexibly change their cooperative preference according to their opponents' strategies in multiple rounds of a prisoner's dilemma (PD) game. Participants in different menstrual phases (32 in the follicular phase [FP] and 30 in the luteal phase [LP]) were asked to complete 20 rounds of PD games with each of three computer opponents holding different cooperative strategies. The results revealed that in PD games that did not require cooperation for increased outcomes, women in the LP (high PROG) reduced their cooperation rate more significantly than women in the FP (low PROG). In contrast, when the game design required reciprocity, simultaneously elevated levels of PROG and oestradiol predicted greater instances of participants choosing to cooperate. Furthermore, we found that elevated PROG levels accounted for women's elevated prosocial choices, regardless of the need to increase outcomes through cooperation. These results implied higher levels of PROG and oestradiol influence women's cooperative strategies resulting in increased social interactions.

Hormonal and psychological influences on performance anxiety in adolescent female volleyball players: a multi-approach study

Background

The neuroendocrine system has important implications for affiliation behavior among humans and can be used to assess the correlation between social relationships, stress, and health. This can be influenced by social closeness; this aspect is the closeness towards another individual or a group of individuals such as a sports team. Sports performance anxiety is considered an unpleasant emotional reaction composed of physiological, cognitive, affective, and behavioral components. This motivates us to learn about the process that can influence the outcome of competition. Hormones and genetics would seem to influence outcome and performance. In this regard, many studies have focused on the exercise response as a function of ovarian hormones and it has been observed that progesterone is a hormone that plays a key role in reducing anxiety, and thus stress, in humans and other animals. On the other hand, high cortisol concentrations are known to contribute to increased anxiety levels. However, the salivary alpha-amylase (sAA) enzyme has been suggested as marker of acute stress than cortisol. Genetics also seem to influence anxiety and stress management as in the case of brain-derived neurotrophic factor (BDNF) and striatal dopamine transporter (DAT). Therefore, the study aims to investigate social closeness, as a measure of sports team cohesion that can influence athletes' performance results, and its ability to influence the secretion of hormones, such as progesterone and cortisol, that affect the management of sports anxiety while also taking into account genetic background during a volleyball match.

Methods

Twenty-six female volleyball players who volunteered participated in this study (mean ± SD: age, 12.07 ± 0.7 years), and played in the final of the provincial volleyball championship in Palermo. All girls were during the ovarian cycle, in detail between the follicular and early ovulatory phases.

Results

The results showed a significant decrease in salivary cortisol only in the winning group (p < 0.039). In fact, whilst in the latter the pre-match level was 7.7 ng/ml and then decreased to 4.5 ng/ml after the match, in the losers group change was not statistically significant (7.8 ng/ml vs 6.6 ng/ml pre- and post-match). As to the sAA concentration, the winning team showed a statistically significant variation between pre- and post-match than the losers (166.01 ± 250 U/ml vs 291.59 ± 241 U/ml) (p = 0.01).

Conclusion

Analyzing the results of the SAS-2 psychological test it is highlighted that, on average, the loser group was more anxious than the winning group, and this contributed to the final result. In conclusion, there is strong evidence supporting the state of the art that many factors can affect performance anxiety and thus the performance itself.

High depressive symptomatology reduces emotional reactions to pictures of social interaction

Individuals with severe depressive symptoms present diminished facial expressions compared to healthy individuals. This reduced facial expression, which occurs in most depressive patients could impair social relationships. The current study sought to investigate whether pictures with social interaction cues could elicit different modulations of facial expressions and mood states in individuals with depressive symptoms compared to healthy individuals. A total of 85 individuals were divided into depressive and non-depressive groups based on their beck depression inventory scores. Participants viewed pictures containing neutral (objects), affiliative (people interacting socially), and control (people not interacting) scenes. Electromyographic signals were collected during the entire period of visualization of the blocks, and emotional questionnaires were evaluated after each block to assess sociability and altruism (prosocial states). In non-depressed individuals, affiliative pictures increased the activity of the zygomatic muscle compared to both neutral and control pictures and reduced fear of rejection compared to neutral pictures. During the visualization of the affiliative block, zygomatic major muscle activation was higher and fear of rejection was lower in the non-depressive individuals than in the depressive. These effects reflected the low expressions of smiling and sociability to affiliative pictures in depressive individuals. These findings highlight the importance of smiling and prosocial states in social interactions, especially in these individuals.

Women in their mid-follicular phase outcompete hormonal contraceptive users, an effect partially explained by relatively greater progesterone and cortisol reactivity to competition

Early evidence suggests that hormonal contraceptive (HC) use alters psychological functioning and competitive behavior. Yet, there is limited data on endocrine models for explaining how HC use affects these outcomes. In this pre-registered and open-data study, we test if HC users and naturally cycling (NC) females in their low (mid-follicular) and high (mid-luteal) progesterone phase differ in competitive persistence and whether progesterone and cortisol reactivity mediate of this effect. HC users (N = 73) in the active hormone-exposure phase and NC participants in the mid-follicular (N = 69) or mid-luteal (N = 72) phase completed two behavioral measures of competitive persistence, holding up a weight for time followed by attempting to solve an unsolvable anagram. Participants also completed measures of handgrip strength and self-reported competitiveness as well as gave saliva samples before and after the tasks for hormone assay. Results showed that NC-follicular group had greater competitive persistence in the weight-holding task compared to both NC-luteal (d = 0.38) and HC use (d = 0.43) groups independent of physical strength and self-reported competitiveness covariates. Although anagram task performance showed similar trends for group differences, analyses for this task were inconclusive. Baseline progesterone did not mediate the effect of cycle phase group on competitive persistence. HC users showed relatively blunted cortisol and progesterone reactivity, and this effect partially mediated the difference in competitive persistence between HC users and the NC-follicular group. In sum, results suggest that HC use could downregulate competitive behavior at least partly by dampening cortisol-progesterone reactivity. These findings offer a new endocrine model for understanding HC use and cycle phase effects on motivational and energetic outcomes required for optimal performance in competitive contexts.

Social Support as a Stress Buffer or Stress Amplifier and the Moderating Role of Implicit Motives: Protocol for a Randomized Study

BACKGROUND

Previous research shows that providing social support in socioevaluative stress situations reduces participants' stress responses. This stress-buffer effect, however, does not hold for everybody, and some studies even found a stress-amplifying effect of social support. Motive disposition research suggests that social motives (affiliation and power) lead to differential and sometimes even opposing affective and physiological responses to interpersonal interaction processes. We here integrate both lines of research and hypothesize that participants with strong affiliation motives benefit, while participants with strong power motives do not benefit from social support in terms of psychobiological responses to a given stressor. Further, participants with strong affiliation and power motives are expected to respond to social support with the arousal of motive-specific affects and reproductive hormone responses (affiliation: progesterone; power: estradiol and testosterone). In addition, we test sex differences in the response to social support and in the strengths of social motives.

OBJECTIVE

The main objective of this study is to test whether social motives and participants' sex moderate the effects of social support in stressful situations.

METHODS

We aim to collect data from 308 participants recruited at our local university. Participants' social motives are assessed using a standardized measure in motive research (Picture Story Exercise). Then, the Trier Social Stress Test for Groups (TSST-G) is used to experimentally induce psychosocial stress. One group of participants receives social support from an associate of the experimenter, while the control group does not receive social support. Stress responses will be assessed by a modified version of the state anxiety scale of the State-Trait Anxiety Inventory and by physiological indicators of stress (cortisol and α-amylase from saliva samples) at 7 measurement points. Reproductive hormones will be analyzed in 4 of these 7 saliva samples. Heart rate and heart rate variability will be assessed continuously. We will additionally measure participants' performance in an interview (part of the TSST-G) using a self-developed categorization system.

RESULTS

The Ethics Committee of the University of Constance approved the application to conduct the study on December 18, 2018. Furthermore, the study was retrospectively registered in the German Clinical Trials Register (DKRS; ID: DRKS00028503) on March 09, 2022. The start of the experiment was planned for the beginning of 2019, but was postponed to June 2021 due to COVID-19. Publication of the first results is planned for spring 2023.

CONCLUSIONS

Our theory-driven integration of social motives in social support research and the precise analysis of sex differences might disentangle inconsistent findings in TSST research. The more faceted view on individual differences has direct implications for applied contexts as it provides a framework for tailored conceptualizations of social support programs.

TRIAL REGISTRATION

German Clinical Trials Register DRKS00028503; https://tinyurl.com/5a87x4da.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

PRR1-10.2196/39509.

Implicit motives as the missing link between visionary leadership, approach and avoidance motivation, and vision pursuit

An unresolved question in visionary leadership research is, why must visions be high in imagery to cause affective reactions and be motivationally effective? Research in motivation psychology has shown that pictorial cues arouse implicit motives. Thus, pictorial cues from vision-induced imagery should arouse a follower’s implicit motives just like a real image. Hence, our fundamental proposition is that follower implicit motives and follower approach motivation serially mediate the relationship between leader vision and followers’ vision pursuit. We also examine the case of negative leader visions, with the central propositions that a negative leader vision arouses a follower’s implicit fear motives and that the follower’s implicit fear motives and follower avoidance motivation serially mediate the relationship between negative leader vision and the follower’s fear-related behaviors. Lastly, we assert that multiple implicit follower motives aroused by a multithematic leader vision exert additive as well as interaction effects on the follower’s vision pursuit. Plain Language Summary An unresolved question in leader vision research concerns why visions need to be high in imagery in order to elicit affective reactions in followers and be motivationally effective? Research in motivation psychology has shown that pictorial cues can arouse a person's implicit motives. It would thus be reasonable to expect that pictorial cues from leader vision-induced imagery arouse a follower's implicit motives just like a real image. Based on this reasoning, our key proposition is that follower implicit motives and follower approach motivation serially mediate the relationship between leader vision and followers' vision pursuit. We also integrate the special case of negative leader visions into our theorizing, with the central propositions that a negative leader vision arouses a follower's implicit fear motives, and that the follower's implicit fear motives and follower avoidance motivation serially mediate the relationship between negative leader vision and the follower's fear-related behaviors. Lastly, based on the distinction between mono- and multithematic visions, the latter of which with the potential to arouse more than one implicit motive simultaneously, we assert that multiple implicit follower motives aroused by a multithematic leader vision exert additive as well as interaction effects on the follower's vision pursuit.

Subjective arousal and perceived control clarify heterogeneity in inflammatory and affective outcomes

Only a portion of individuals experiencing chronic stress and associated increases in inflammation go on to develop pathological elevations in mood and anxiety symptoms. Some prevailing models suggest that the outcomes of chronic stress may largely depend on individual differences in perceived control. In the current study, we used this theoretical framework to disambiguate the influence of autonomic arousal and perceived control on inflammatory and psychological outcomes in a large sample of adults from the Midlife in the United States dataset (wave 2; MIDUS-2) (Final N ​= ​1030), and further replicated our approach in a second (MIDUS-Refresher) cohort (Final N ​= ​728). Using k-means clustering we created subgroups systematically differing in subjective arousal (high/low) and perceived control (low/high) and compared these subgroups on inflammatory markers and psychological outcomes. Overall results showed that individuals in the high subjective arousal subgroups had higher levels of IL-6, CRP, and FIB, independent of level of CNTL. However, distinctive, and pathological psychological symptom patterns became more apparent when individuals were characterized by both subjective arousal and perceived control. These findings suggest that subtyping individuals based on subjective arousal and perceived control can help us disentangle pathological versus adaptive mental health outcomes in those with co-occurring inflammation and may help identify those vulnerable to psychopathology in the context of physical or psychological stressor exposure.

CortiLove: A pilot study on hair steroids in the context of being in love and separation

While romantic infatuation and separation influence psychological and physiological functioning, the hypothalamic-pituitary-adrenal axis with its biomarkers cortisol, dehydroepiandrosterone (DHEA), and progesterone central for coping and distress has been scarcely researched in this context. In particular, endocrine hair analyses assumed to be more valid than saliva or blood assessments for studying long-term processes have not yet been conducted in the context of romantic love. Thus, 101 female subjects in phases of infatuation (n = 16), separation (n = 14), long-term relationships (n = 40), and singlehood (n = 31) reported psychological distress and provided 1 cm hair samples for the assessment of long-term integrated cortisol, DHEA, and progesterone over the last month. Separated, infatuated, and single women exhibited higher cortisol levels than those in a long-term relationship (all ps ≤ .031), while self-reported distress was only evident in separated individuals. Further, no group differences for progesterone (p = .602), but higher DHEA levels in the separation (p = .009) and single group (p = .016) compared to the long-term relationship group were detected. This is the first study showing that compared to women in long-term relationships, infatuation, separation, and single groups exhibit higher levels of physiological, but not necessarily self-reported indicators of distress. These findings, albeit on a very small and preliminary sample, are discussed in the context of the stress-buffering effect of relationships, and provide important starting points for bigger, more balanced studies combining multimodal self-report and biological markers in psychological research of romantic love.

•

Higher hair cortisol in separation, infatuation, singlehood vs. stable relationship.

•

Higher hair DHEA only in separation and singlehood vs. stable relationship.

•

No group difference for progesterone.

•

Divergence of physiological and self-reported indicators of distress.

The Relationship Between Multidimensional Motivation and Endocrine-Related Responses: A Systematic Review

Multidimensional motivational theories postulate that the type of motivation is as important as the quantity of motivation, with implications for human functioning and well-being. An extensive amount of research has explored how constructs contained within these theories relate to the activation of the endocrine system. However, research is fragmented across several theories, and determining the current state of the science is complicated. In line with contemporary trends for theoretical integration, this systematic review aims to evaluate the association between multidimensional motivational constructs and endocrine-related responses to determine which theories are commonly used and what inferences can be made. Forty-one studies were identified incorporating five distinct motivation theories and multiple endocrine-related responses. There was evidence across several theories that high-quality motivation attenuated the cortisol response in evaluative environments. There was also evidence that motivational needs for power and affiliation were associated with lower and higher levels of salivary immunoglobulin A, respectively. The need for power may play a role in increasing testosterone when winning a contest; however, this evidence was not conclusive. Overall, this review can shape the future integration of motivational theories by characterizing the nature of physiological responses to motivational processes and examining the implications for well-being.

Estradiol and progesterone as resilience markers? - Findings from the Swiss Perimenopause Study

While resilience seems to be associated with a variety of biological markers, studies assessing such correlates in women during the perimenopause are lacking. The perimenopause constitutes a phase of major biopsychosocial changes, during which the sex hormones estradiol (E2) and progesterone (P4) eventually decrease significantly. The aim of this study was to examine the extent to which the declining levels of E2 and P4 serve as resilience markers in perimenopausal women. In 129 healthy perimenopausal women aged 40-56 years, saliva samples were collected on every fourth day over a period of four weeks in order to investigate E2 and P4 levels. All participants completed psychosocial questionnaires including variables related to resilience, well-being, and mental health. Perimenopausal status was determined using the Stages of Reproductive Aging Workshop (STRAW) criteria. The results indicate that P4 is linked to psychosocial resilience. More precisely, women with higher P4 levels seem to be more resilient than women with lower P4 levels, irrespective of the perimenopausal status. No such relation was found for E2 levels. Further analyses revealed that women with higher P4 levels experience significantly higher life satisfaction, lower perceived stress, and lower depressive symptoms than women with lower P4 levels. Accordingly, P4 can be considered as a biological marker of resilience in perimenopause.

Suitability of saliva stimulants for valid assessment of steroid hormones via radioimmunoassay

Salivary steroid measurement is a popular way to assess endocrine hormone levels, but efficient sample collection can be challenging because the use of stimulants can interfere with valid measurement. The aim of this study was therefore to identify a stimulant that can be used in assessment of the steroid hormones cortisol (C), testosterone (T), progesterone (P) and estradiol (E2) without impairing their quantification by radioimmunoassay. Study 1 and 2 explored the suitability of potential stimulants in comparison to unstimulated saliva collection. Study 3 tested stimulants under standardized conditions in water. Across all three studies, Parafilm® wax foil performed best and was therefore tested once more and validated as a saliva stimulant in Study 4. No significant differences between unstimulated saliva and Parafilm®-stimulated saliva could be found for any of the four hormones assayed. Therefore, Parafilm® appears to be a suitable saliva flow stimulant for assaying the salivary steroid hormones C, T, P and E2 by radioimmunoassay.

Endocrinological effects of social exclusion and inclusion: Experimental evidence for adaptive regulation of female fecundity

When current conditions are probabilistically less suitable for successful reproduction than future conditions, females may prevent or delay reproduction until conditions improve. Throughout human evolution, social support was likely crucial to female reproductive success. Women may thus have evolved fertility regulation systems sensitive to cues from the social environment. However, current understanding of how psychological phenomena might affect female ovarian function is limited. In this study, we examined whether cues of reduced social support-social ostracism-impact women's hormone production. Following an in-lab group bonding task, women were randomly assigned to a social exclusion (n = 88) or social inclusion (n = 81) condition. After social exclusion, women with low background levels of social support experienced a decrease in estradiol relative to progesterone. In contrast, socially-included women with low background social support experienced an increase in estradiol relative to progesterone. Hormonal changes in both conditions occurred specifically when women were in their mid-to-late follicular phase, when baseline estradiol is high and progesterone is low. Follow-up analyses revealed that these changes were primarily driven by changes in progesterone, consistent with existing evidence for disruption of ovarian function following adrenal release of follicular-phase progesterone. Results offer support for a potential mechanism by which fecundity could respond adaptively to the loss or lack of social support.

Pictures of social interaction prompt a sustained increase of the smile expression and induce sociability

Viewing pictures of social interaction can facilitate approach behaviors. We conducted two studies to investigate if social interaction cues, empathy, and/or social touch modulate facial electromyographic (EMG) reactivity (as evidenced by the zygomaticus major and corrugator supercilii muscles) and mood states. We presented bonding pictures (depicting social interaction) and control pictures (without social interaction) while continuously recording zygomatic and corrugator EMG activities. In both studies, picture blocks were paired by valence and arousal. All participants were college students. In study 1, participants (n = 80, 47 women) read relevant priming texts immediately before viewing each block of 14 pictures. In study 2, participants did not read (n = 82, 63 women) priming texts before each block of 28 pictures. In study 1 and study 2, participants also completed mood states questionnaires to assess sociability and altruistic behavior. Empathy and social touch frequency were also assessed by self-reported questionnaires. In both studies, bonding pictures increased the zygomatic activity and the self-reported sociability feeling compared to control pictures. Only in study 2, bonding pictures decreased median corrugator activity compared to control pictures. We concluded that social interaction cues were efficient to increase sociability and prompt a sustained smile expression regardless of priming texts.

The endocrinology of female friendships: Cortisol and progesterone attunement after separation

Friendships constitute important relationships, and often function to reduce stress, but have been under-studied. In mother-child dyads, infants coordinate their stress response with their caregivers without experiencing the stressor themselves. The current study used a modified version of the Trier Social Stress Test to examine whether i) friends are physiologically attuned (i.e., cortisol and progesterone); ii) attunement differs as a function of social acceptance or rejection external to the dyad; and, iii) friends can 'catch' a stress response only through non-verbal cues. Friends showed both cortisol and progesterone attunement at the beginning of the study. Friends showed cortisol attunement across time and conditions. Friends' progesterone levels were significantly, but negatively associated across time and conditions. They did not, however, show a stress contagion as a result of one friend experiencing stress. These findings suggest that cortisol and progesterone play different roles in the attunement of stress and subsequent affiliation.

The role of the microbiome in the neurobiology of social behaviour

Microbes colonise all multicellular life, and the gut microbiome has been shown to influence a range of host physiological and behavioural phenotypes. One of the most intriguing and least understood of these influences lies in the domain of the microbiome's interactions with host social behaviour, with new evidence revealing that the gut microbiome makes important contributions to animal sociality. However, little is known about the biological processes through which the microbiome might influence host social behaviour. Here, we synthesise evidence of the gut microbiome's interactions with various aspects of host sociality, including sociability, social cognition, social stress, and autism. We discuss evidence of microbial associations with the most likely physiological mediators of animal social interaction. These include the structure and function of regions of the 'social' brain (the amygdala, the prefrontal cortex, and the hippocampus) and the regulation of 'social' signalling molecules (glucocorticoids including corticosterone and cortisol, sex hormones including testosterone, oestrogens, and progestogens, neuropeptide hormones such as oxytocin and arginine vasopressin, and monoamine neurotransmitters such as serotonin and dopamine). We also discuss microbiome-associated host genetic and epigenetic processes relevant to social behaviour. We then review research on microbial interactions with olfaction in insects and mammals, which contribute to social signalling and communication. Following these discussions, we examine evidence of microbial associations with emotion and social behaviour in humans, focussing on psychobiotic studies, microbe-depression correlations, early human development, autism, and issues of statistical power, replication, and causality. We analyse how the putative physiological mediators of the microbiome-sociality connection may be investigated, and discuss issues relating to the interpretation of results. We also suggest that other candidate molecules should be studied, insofar as they exert effects on social behaviour and are known to interact with the microbiome. Finally, we consider different models of the sequence of microbial effects on host physiological development, and how these may contribute to host social behaviour.

The closer you feel, the more you care: Positive associations between closeness, pain intensity rating, empathic concern and personal distress to someone in pain

Previous research revealed inconsistent findings regarding affective responses when facing someone in pain (i.e., empathic concern and/or personal distress). In this paper, we suggest that the degree of closeness between the observer and the person in pain may account for these contradictory results, such that greater closeness towards this person leads to higher personal distress. To test this hypothesis, we induced either low or high closeness with a confederate in 69 randomly assigned participants. Following the closeness induction, participants evaluated their affective responses (empathic concern and personal distress) and rated the confederate's pain intensity after watching the confederate undergoing a painful cold pressure task. Results showed that, despite the non-significant effect of closeness induction, closeness across both conditions (low and high) was positively correlated with pain intensity rating, empathic concern and personal distress. This study thus suggests that closeness is associated with higher cognitive and affective responses to a person in pain.

Association of ovarian hormones with mapping concept of self and others in the brain's default mode network

The brain's default mode network (DMN) has become closely associated with self-referential mental activity, particularly in the resting-state. Prior reports point that the sex hormones are potent modulators of brain plasticity and functional connectivity. However, it is uncertain whether changes in ovarian hormones, as occur during the monthly menstrual cycle, substantially affects the functional connectivity of DMN. Here, we employed a Self-Awareness Scale (SAS) and the resting-state functional MRI in the late follicular phase and the mid-luteal phase to investigate the effect of the estradiol (E2) and progesterone on the SAS and DMN. On the behavioral level, increased progesterone facilitated women's other-focused attention. The regions of interest-based resting-state functional connectivity analyses continued to demonstrate a negative correlation of the relative progesterone and the medial prefrontal cortex-inferior temporal gyrus (mPFC-ITG) functional connectivity, and a facilitated effect of relative E2 on the mPFC-inferior parietal lobule functional connectivity in the DMN. Furthermore, as a core hub of the 'theory of mind', the functional connectivity between the ITG and thalamus was found negatively correlated with the relative E2. Meanwhile, the mid-luteal phase, which had significantly lower relative E2 levels, was indicated had stronger ITG-thalamus functional connectivity during the resting state. These results demonstrated an opposite effect of E2 and progesterone on the DMN and the other-focused preference in the mid-luteal phase, extended previous evidence of the potentially adaptive psychological effects of ovarian hormones on mapping self and others in the brain networks.

Does women's anxious jealousy track changes in steroid hormone levels?

Findings for progesterone and anxiety in non-human animals led to the hypothesis that women's interpersonal anxiety will track changes in progesterone during the menstrual cycle. There have been few direct tests of this hypothesis, however. Consequently, we used a longitudinal design to investigate whether interpersonal anxiety (assessed using the anxious jealousy subscale of the relationship jealousy questionnaire) tracked changes in salivary steroid hormones during the menstrual cycle in a large sample of young adult women. We found no evidence for within-subject effects of progesterone, estradiol, their interaction or ratio, testosterone, or cortisol on anxious jealousy. There was some evidence that other components of jealousy (e.g., reactive jealousy) tracked changes in women's cortisol, however. Collectively, these results provide no evidence for the hypothesis that interpersonal anxiety tracks changes in progesterone during the menstrual cycle.

Meta-Analysis of the RDoC Social Processing Domain across Units of Analysis in Children and Adolescents

OBJECTIVE

This meta-analysis advances a framework to understand correspondence among units of analysis of the social processing construct within Research Domain Criteria (RDoC).

METHOD

As requested for this special issue, eligible studies cited an RDoC-initiative paper or mentioned RDoC in the abstract, title, or keywords were empirical and peer reviewed, and described a correlation or regression analysis (r, β, or odds ratio) between two different units of analysis in the social processing domain in youth. We examined the frequency (descriptive statistics) and magnitude of correspondence between unit-pairs (random effects models), and predefined moderators (meta-regression).

RESULTS

Eight of the twenty-eight possible unit-by-unit pairs were identified, with subjective-by-behavior units being the most common. Of those, only subjective-by-circuit had significant correspondence between units. Moderator analysis revealed that the age and diagnosis of generalized anxiety disorder moderated correspondence between subjective-by-circuit units of analysis, and that a diagnosis of autism spectrum disorder moderated correspondence between subjective-by-gene units of analysis. Younger ages and inclusion of either diagnostic group reduced correspondence.

CONCLUSIONS

These findings indicate that the RDoC initiative has generated limited research within the social processing domain across units of analysis in youth to date. Moreover, National Institute of Mental Health (NIMH)-funded studies do not appear to be biased toward supporting the RDoC framework. However, the limited number of included studies precludes the generalizability of these findings and underscores the need for further research. Despite this, results suggest that the NIMH model for providing standard batteries of measurement tools may effectively reduce spurious correlations between subjective-by-behavior units of analysis.

Endocrine Regulations in Human-Dog Coexistence through Domestication

Endocrine system regulation is important for the maintenance of homeostasis; it controls hormonal functions in complex physiology and behavior and adaptations to social environments. Evidence indicates that for more than 35 000 years, dogs (Canis familiaris) have been domesticated through living with humans. For example, they have acquired human-like social skills, such as eye gazing and pointing gestures. These unique behaviors are, at least partially, regulated by hormones and are thought to have been genetically altered throughout domestication. Glucocorticoids affect social tolerance, while oxytocin facilitates social coordination and familiarity between individuals. We review historical and recent literature to facilitate an understanding of the roles of glucocorticoid and oxytocin functions in the human-canine coexistence dynamic established during domestication.

Increased sensitivity to social exclusion during the luteal phase: Progesterone as resilience factor buffering against ostracism?

A woman's social behaviour reportedly varies across the menstrual cycle. In this study, we estimated changes in sensitivity to social exclusion across the menstrual cycle and scrutinized the related role of progesterone. Forty-nine naturally cycling women played a virtual ball-tossing game (Cyberball) to manipulate social inclusion. All participants underwent inclusion and exclusion conditions during the late follicular and the luteal phase. We assessed salivary progesterone concentrations at each cycle phase. After each Cyberball session we measured positive/negative mood using the Multidimensional Mood State Questionnaire (MDMQ). Multilevel analyses indicated that women showed worse mood following exclusion as compared to inclusion conditions (p = 0.014). Notably, this exclusion effect was more pronounced during the luteal phase than the late follicular phase (p = 0.029). As expected, progesterone concentrations were higher during the luteal phase as compared to the late follicular phase, but interestingly, progesterone concentrations were negatively associated with exclusion effects. When accounting for mediation via progesterone, direct cycle-phase related differences in social exclusion effects even increased as compared to the model without mediator. These findings suggest that progesterone may function as buffer against negative feelings that result from being socially excluded. The relevance of these findings for Premenstrual Dysphoric Disorder (PMDD) are discussed, and we conclude that social exclusion may represent an important research domain criterion (RDoC) of relevance for PMDD, with progesterone pointing to new potential pharmacological targets.

Repeatedly adopting power postures does not affect hormonal correlates of dominance and affiliative behavior

Background

Adopting expansive vs. constrictive postures related to high vs. low levels of social power has been suggested to induce changes in testosterone and cortisol levels, and thereby to mimic hormonal correlates of dominance behavior. However, these findings have been challenged by several non-replications recently. Despite this growing body of evidence that does not support posture effects on hormone levels, the question remains as to whether repeatedly holding postures over time and/or assessing hormonal responses at different time points would yield different outcomes. The current study assesses these methodological characteristics as possible reasons for previous null-findings. Additionally, it investigates for the first time whether expansive and constrictive postures impact progesterone levels, a suggested correlate of affiliative motives and behavior. By testing the effects of repeated but short posture manipulations in between the blocks of a social task while using a cover story, it further fulfills the conditions previously raised as potentially necessary for the effects to occur.

Methods

A total of 82 male participants repeatedly adopted an expansive or constrictive posture for 2 min in between blocks of a task that consisted in categorizing faces based on first impressions. Saliva samples were taken at two different time points in a time window in which hormonal responses to stress, competition and other manipulations are known to be strongest.

Results

Neither testosterone and cortisol levels linked to dominance behaviors, nor progesterone levels related to affiliative tendencies, responded differently to adopting expansive as opposed to constrictive postures. The present results suggest that even repeated power posing in a context where social stimuli are task-relevant does not elicit changes in hormone levels.

Interaction of hormonal and social environments in understanding body image concerns in adolescent girls

During adolescence, peer approval becomes increasingly important and may be perceived as contingent upon appearance in girls. Concurrently, girls experience hormonal changes, including an increase in progesterone. Progesterone has been implicated in affiliative behavior but inconsistently associated with body image concerns. The current study sought to examine whether progesterone may moderate the association between perceived social pressures to conform to the thin ideal and body image concerns. Secondary analyses were conducted in cross-sectional data from 813 girls in early puberty and beyond (ages 8-16) who completed assessments of the peer environment, body image concerns, and progesterone. Models for mediation and moderation were examined with BMI, age, and menarcheal status as covariates. Belief that popularity was linked to appearance and the experience of weight-related teasing were both positively associated with greater body image concerns, but neither was associated with progesterone once adjusting for covariates. Progesterone significantly interacted with perceived social pressures in predicting body image concerns. At higher progesterone levels, appearance-popularity beliefs and weight-related teasing were more strongly related to body image concerns than they were at lower progesterone levels. Findings support a moderating role for progesterone in the link between social pressures and body image concerns in girls. This study adds to a growing literature examining how girls' hormonal environments may modulate responses to their social environments. Longitudinal and experimental work is needed to understand temporal relations and mechanisms behind these associations.

Post-encoding stress enhances mnemonic discrimination of negative stimuli

Stress influences how we remember emotional events and how these events shape future behaviors. However, the impact of stress on memory specificity for emotional events has yet to be examined. To this end, the present study utilized a mnemonic discrimination task that taxes hippocampal pattern separation, the process of distinguishing between overlapping experiences, thereby allowing us to better understand the mechanisms by which stress affects gist versus detail memory of emotional events. Participants encoded scenes composed of negative or neutral objects placed on neutral backgrounds and then underwent a psychosocial stressor or matched control task. Twenty-four hours later during testing, objects were presented separately, with some identical old objects (targets), some new objects (foils), and some similar but not identical objects (lures). Target recognition was enhanced for negative compared to neutral objects in both the stress and control groups. Interestingly, post-encoding stress selectively enhanced mnemonic discrimination of negative versus neutral objects, which was not the case in the control group. Measures of salivary cortisol revealed a quadratic inverted U relationship between negative mnemonic discrimination and cortisol increase. These findings suggest that moderate cortisol release following stress is associated with enhanced memory precision for negative information.

Do Implicit Motives Influence Perceived Chronic Stress and Vital Exhaustion?

Vital exhaustion (VE) results from the experience of chronic stress. However, research on stress types and their relation to VE is rare. Moreover, the role of implicit motives in these processes has not yet been investigated. Analysis included 101 vitally exhausted men aged 40-65 years. Participants provided self-report data on their experience of chronic stress and social support. Subtypes of work-related and social stress were positively associated with VE. Implicit affiliation and achievement motives were linked to social support and chronic stress, and indirectly to VE. Moreover, they moderated the relationship between stress and exhaustion. In conclusion, implicit motives are key factors in the stress process: They are involved in an individual's experience of stress and stress-related consequences for mental health.

Immediate and delayed neuroendocrine responses to social exclusion in males and females

Social exclusion is a complex phenomenon, with wide-ranging immediate and delayed effects on well-being, hormone levels, brain activation and motivational behavior. Building upon previous work, the current fMRI study investigated affective, endocrine and neural responses to social exclusion in a more naturalistic Cyberball task in 40 males and 40 females. As expected, social exclusion elicited well-documented affective and neural responses, i.e., increased anger and distress, as well as increased exclusion-related activation of the anterior insula, the posterior-medial frontal cortex and the orbitofrontal cortex. Cortisol and testosterone decreased over the course of the experiment, whereas progesterone showed no changes. Hormone levels were not correlated with subjective affect, but they were related to exclusion-induced neural responses. Exclusion-related activation in frontal areas was associated with decreases in cortisol and increases in testosterone until recovery. Given that results were largely independent of sex, the current findings have important implications regarding between-sex vs. within-sex variations and the conceptualization of state vs. trait neuroendocrine functions in social neuroscience.

Progesterone and women's anxiety across the menstrual cycle

Animal models and a few human investigations suggest progesterone may be associated with anxiety. Progesterone naturally fluctuates across the menstrual cycle, offering an opportunity to understand how within-person increases in progesterone and average progesterone levels across the cycle correspond to women's anxiety. Across two longitudinal studies, we simultaneously modeled the between- and within-person associations between progesterone and anxiety using multilevel modeling. In Study 1, 100 Polish women provided saliva samples and reported their anxiety at three phases of the menstrual cycle: follicular, peri-ovulatory, and luteal. A significant between-person effect emerged, revealing that women with higher average progesterone levels across their cycles reported higher levels of anxiety than women with lower progesterone cycles. This effect held controlling for estradiol. In Study 2, 61 American women provided saliva samples and reported their attachment anxiety during laboratory sessions during the same three cycle phases. A significant between-person and within-person association emerged: women with higher average progesterone levels reported higher levels of attachment anxiety, and as women's progesterone levels increased across their cycles, so too did their attachment anxiety. These effects held controlling for cortisol. In sum, both studies provide support for a link between menstrual cycle progesterone levels and subjective anxiety.

Stability of and Changes in Implicit Motives. A Narrative Review of Empirical Studies

Although growing research indicates that certain personality traits change over the lifespan, implicit motives are often deemed to be rather stable personality characteristics. Researchers have been interested in implicit motives for several decades, but our understanding of how these dispositions change still lacks clarity. This article gives an overview and a discussion of the current evidence for the stability of and the changes in implicit motives. After elaborating on the theoretical background of the motive construct and its measurement, we present an overview of studies that have investigated the trainability of implicit motives and their dispositional stability and changes using cross-sectional and longitudinal methods. Although the results are inconclusive concerning the direction of change, the reviewed studies suggest that implicit motives adapt to life circumstances much like other personality traits. This review sets out to contribute to a better understanding of the functioning of implicit motives and to present a roadmap for further research.

Endocrine and aggressive responses to competition are moderated by contest outcome, gender, individual versus team competition, and implicit motives

This study examined hormonal responses to competition in relation to gender, social context, and implicit motives. Participants (N = 326) were randomly assigned to win or lose in a 10-round, virtual face-to-face competition, in same-sex individual- and team-competition contexts. Saliva samples, taken before and twice after the competition, were assayed for testosterone (T), estradiol (E), progesterone (P), and cortisol (C). Implicit needs for power (nPower) and affiliation (nAffiliation) were assessed with a picture-story exercise before the competition. Aggression was measured via the volume at which participants set noise blasts for their opponents. Men competing individually and women competing as teams showed similar T increases after winning. C was differentially associated with outcome in the team matches, with higher post-match cortisol for winning women, and an opposite effect for male teams. Analyses including implicit motives indicated that situational variables interacted with motivational needs in shaping hormonal responses to competition: in naturally cycling women, nPower predicted T increases after winning and T and E decreases after losing. In men, nPower predicted T increases after losing and decreases after winning. In male teams, nPower predicted C increases after losing, but not after winning, whereas in individual competitions, nPower was a general negative predictor of C changes in women. nAffiliation predicted P increases for women competing as teams, and P decreases for women competing individually. Aggression was higher in men, losers, and teams than in women, winners, and individuals. High aggression was associated with high baseline C in women competing individually and with low baseline C and C decreases in women competing as teams and in men generally. Our findings suggest that while situational and gender factors play a role in hormonal responses to competition, they also depend on their interplay with motivational factors. They also suggest that while aggression is strongly affected by situational factors in the context of a competition, it has no direct association with motivational and hormonal correlates of dominance (nPower, T, E) and instead is associated with (mostly) low levels of C.

Sex differences in cortisol's regulation of affiliative behavior

A contribution to a special issue on Hormones and Human Competition. A stress perspective is used to illuminate how competitive defeat and victory shape biology and behavior. We report a field study examining how change in cortisol following perceived defeat (vs. victory) in a competition-in this case, a dog agility competition-relates to affiliative behavior. Following competition, we measured cortisol change and the extent to which dog handlers directed affiliative behaviors toward their dogs. We found striking sex differences in affiliation. First, men were more affiliative toward their dogs after victory, whereas women were more affiliative after defeat. Second, the greater a female competitor's increase in cortisol, the more time she spent affiliating with her dog, whereas for men, the pattern was the exact opposite: the greater a male competitor's increase in cortisol, the less time he spent affiliating with his dog. This pattern suggests that, in the wake of competition, men and women's affiliative behavior may serve different functions-shared celebration for men; shared consolation for women. These sex differences show not only that men and women react very differently to victory and defeat, but also that equivalent changes in cortisol across the sexes are associated with strikingly different behavioral consequences for men and women.

Hormonal systems, human social bonding, and affiliation

Which hormones are implicated in human social bonding and affiliation? And how does field research speak to this issue? We begin by laying out a broad view of how endocrine hormones in general modulate life history allocations of energy and other resources, and the ways in which their neuromodulatory functions must be understood within a broader conceptualization of how they have been shaped to affect allocations. We then turn to four specific hormones or hormone families that have received much attention: oxytocin, opioids, prolactin, and progesterone. Each plays a role in regulating psychological capacities and propensities that underlie individuals' interactions with important social targets. Yet in no case is it clear exactly what regulatory roles these hormones play. We suggest several directions for future research.

Women recovering from social rejection: The effect of the person and the situation on a hormonal mechanism of affiliation

Rejection can motivate either affiliation or withdrawal. In order to study how personality and situational variables influence whether women will be motivated to affiliate versus withdraw, we manipulate social feedback (rejection vs. acceptance) and opportunity for face-to-face interaction (blocked vs. face-to-face) and measure the individual difference variables rejection sensitivity and social anxiety. We test how these variables affect endogenous progesterone and cortisol concentrations, which are presumed to signal motivational responses to rejection. We find that three-way interactions involving social feedback, opportunity for face-to-face interactions, and either social anxiety or rejection sensitivity significantly predict progesterone change, but not cortisol change. Both interactions are driven by sharp progesterone decreases for women high in social anxiety/rejection sensitivity who have been rejected and who have no opportunity to reaffiliate in a face-to-face interaction. This progesterone change may be a physiological marker of motivation for social avoidance following rejection for women who cannot reaffiliate and who are particularly socially anxious or sensitive to rejection.

Implicit Motives and Men's Perceived Constraint in Fatherhood

Research shows that implicit motives influence social relationships. However, little is known about their role in fatherhood and, particularly, how men experience their paternal role. Therefore, this study examined the association of implicit motives and fathers’ perceived constraint due to fatherhood. Furthermore, we explored their relation to fathers’ life satisfaction. Participants were fathers with biological children (N = 276). They were asked to write picture stories, which were then coded for implicit affiliation and power motives. Perceived constraint and life satisfaction were assessed on a visual analog scale. A higher implicit need for affiliation was significantly associated with lower perceived constraint, whereas the implicit need for power had the opposite effect. Perceived constraint had a negative influence on life satisfaction. Structural equation modeling revealed significant indirect effects of implicit affiliation and power motives on life satisfaction mediated by perceived constraint. Our findings indicate that men with a higher implicit need for affiliation experience less constraint due to fatherhood, resulting in higher life satisfaction. The implicit need for power, however, results in more perceived constraint and is related to decreased life satisfaction.

The endocrinology of human caregiving and its intergenerational transmission

Variation in the quality of parental care has a tremendous impact on a child's social–emotional development. Research investigating the predictors of this variability in human caregiving behavior has mostly focused on learning mechanisms. Evidence is currently accumulating for the complementary underlying role of steroid hormones and neuropeptides. An overview is provided of the hormones and neuropeptides relevant for human caregiving behavior. Then the developmental factors are described that stimulate variability in sensitivity to these hormones and neuropeptides, which may result in variability in the behavioral repertoire of caregiving. The role of genetic variation in neuropeptide and steroid receptors, the role of testosterone and oxytocin during fetal development and parturition, and the impact of experienced caregiving in childhood on functioning of the neuroendocrine stress and oxytocin system are discussed. Besides providing a heuristic framework for further research on the ontogenetic development of human caregiving, a neuroendocrine model is also presented for the intergenerational transmission of caregiving practices. Insight into the underlying biological mechanisms that bring about maladaptive caregiving behavior, such as neglect and insensitive parenting, will hopefully result in more efficient approaches to reduce the high prevalence of such behavior and to minimize the impact on those affected.

Effects of intranasal oxytocin on steroid hormones in men and women

BACKGROUND

Recent interest in the social and cognitive effects of intranasal oxytocin prompts a need for understanding its physiological effects in humans. Few studies have examined the effects of intranasal oxytocin on steroid hormones. Filling this gap is especially important given the evidence that steroid hormones participate in some of the same behavioral functions as oxytocin, e.g. in stress, processing of emotional stimuli, aggression, trust, empathy, and parental care.

METHODS

In randomized, double-blind experiments, we administered oxytocin (24 IU) or saline placebo to 97 healthy participants. Saliva samples were collected before and at several time points after the oxytocin/placebo administration to assess the levels of cortisol, progesterone, and testosterone.

RESULTS

Oxytocin had no effects on testosterone, progesterone, or cortisol in women or men.

CONCLUSION

Acute intranasal oxytocin does not affect the levels of cortisol, testosterone or progesterone in humans, at least in the absence of a stressful context. These data suggest that acute oxytocin does not have a direct impact on the human hypothalamic-pituitary-adrenal or hypothalamic-pituitary-gonadal axes under nonstressful circumstances. This knowledge helps rule out potential mechanisms for some of the effects of oxytocin in humans and adds to the generally limited body of knowledge on the basic physiological or psychological effects of intranasal oxytocin in human beings.

Histories of abuse predict stronger within-person covariation of ovarian steroids and mood symptoms in women with menstrually related mood disorder

OBJECTIVE

Individual differences in sensitivity to cyclical changes in ovarian steroids estradiol (E2) and progesterone (P4) have been implicated in the pathophysiology of menstrually related mood disorder (MRMD). However, no prospective studies have investigated psychosocial risk factors for sensitivity to hormone effects on mood in MRMD. Using a repeated measures approach and multilevel models, we tested the hypothesis that a history of abuse provides a context in which within-person elevations of E2 and P4 prospectively predict daily symptoms.

METHOD

66 women with prospectively-confirmed MRMD recruited for a trial of oral contraceptives provided 1 month of baseline hormone and mood data prior to randomization. Lifetime physical and sexual abuse experiences were assessed. Across one cycle, women completed daily measures of symptoms and provided blood samples on 5 days across the menstrual cycle. Current E2 and P4 were centered within person (CWP) such that higher values represented cyclical elevations in hormones.

RESULTS

Rates of physical (27%) and sexual (29%) abuse were high, consistent with previous work documenting a link between trauma and MRMD. In women with a history of physical abuse, cyclical increases in P4 predicted greater mood and interpersonal symptoms on the three days following that sample. In women with a history of sexual abuse, cyclical increases in E2 predicted greater anxiety symptoms on the three days following that sample.

CONCLUSIONS

Results inform further inquiry into the role of severe life stressors and stress response systems in MRMD. We discuss areas for future research on the psychosocial and physiological pathways through which abuse may influence the link between hormones and symptoms.

Gamma-hydroxybutyrate enhances mood and prosocial behavior without affecting plasma oxytocin and testosterone

Gamma-hydroxybutyrate (GHB) is a GHB-/GABAB-receptor agonist. Reports from GHB abusers indicate euphoric, prosocial, and empathogenic effects of the drug. We measured the effects of GHB on mood, prosocial behavior, social and non-social cognition and assessed potential underlying neuroendocrine mechanisms. GHB (20mg/kg) was tested in 16 healthy males, using a randomized, placebo-controlled, cross-over design. Subjective effects on mood were assessed by visual-analogue-scales and the GHB-Specific-Questionnaire. Prosocial behavior was examined by the Charity Donation Task, the Social Value Orientation test, and the Reciprocity Task. Reaction time, memory, empathy, and theory-of-mind were also tested. Blood plasma levels of GHB, oxytocin, testosterone, progesterone, dehydroepiandrosterone (DHEA), cortisol, aldosterone, and adrenocorticotropic-hormone (ACTH) were determined. GHB showed stimulating and sedating effects, and elicited euphoria, disinhibition, and enhanced vitality. In participants with low prosociality, the drug increased donations and prosocial money distributions. In contrast, social cognitive abilities such as emotion recognition, empathy, and theory-of-mind, and basal cognitive functions were not affected. GHB increased plasma progesterone, while oxytocin and testosterone, cortisol, aldosterone, DHEA, and ACTH levels remained unaffected. GHB has mood-enhancing and prosocial effects without affecting social hormones such as oxytocin and testosterone. These data suggest a potential involvement of GHB-/GABAB-receptors and progesterone in mood and prosocial behavior.

Testing the Affiliation Hypothesis of Homoerotic Motivation in Humans: The Effects of Progesterone and Priming

The frequency of homoerotic behavior among individuals who do not identify as having an exclusively homosexual sexual orientation suggests that such behavior potentially has adaptive value. Here, we define homoerotic behavior as intimate erotic contact between members of the same sex and affiliation as the motivation to make and maintain social bonds. Among both male and female nonhuman primates, affiliation is one of the main drivers of homoerotic behavior. Correspondingly, in humans, both across cultures and across historical periods, homoerotic behavior appears to play a role in promoting social bonds. However, to date, the affiliation explanation of human homoerotic behavior has not been adequately tested experimentally. We developed a measure of homoerotic motivation with a sample of 244 men and women. Next, we found that, in women (n = 92), homoerotic motivation was positively associated with progesterone, a hormone that has been shown to promote affiliative bonding. Lastly, we explored the effects of affiliative contexts on homoerotic motivation in men (n = 59), finding that men in an affiliative priming condition were more likely to endorse engaging in homoerotic behavior compared to those primed with neutral or sexual concepts, and this effect was more pronounced in men with high progesterone. These findings constitute the first experimental support for the affiliation account of the evolution of homoerotic motivation in humans.

Public speaking in front of an unreceptive audience increases implicit power motivation and its endocrine arousal signature

The present study explored the motivational characteristics of the Trier Social Stress Test (TSST; Kirschbaum, Pirke, & Hellhammer, 1993). Seventy-two participants either completed the public-speaking component of the TSST or, as a control condition, the friendly TSST (Wiemers, Schoofs, & Wolf, 2013) and wrote picture stories both before and after treatment. Stories were coded for motivational imagery related to power, achievement, and affiliation as well as for activity inhibition, a marker of functional brain lateralization during stress. The TSST had a specific arousing effect on power motivation, but not on other motivational needs, on activity inhibition, or on story length. TSST-elicited increases in power imagery, but not in achievement or affiliation imagery, were associated with a relatively greater salivary alpha-amylase response and with a relatively lesser salivary cortisol response. These findings suggest that the TSST specifically induces power-related stress.