The hormonal correlates of implicit power motivation

The role of "Social" in the TSST: Social support and social motives partly moderate psychobiological stress responses in addition to biological sex

Prior research has highlighted sex differences in psychobiological stress responses during the Trier Social Stress Test (TSST). This study expands on these findings by exploring how social motives (affiliation and power motives) and social support, as direct predictors and in interaction with biological sex, influence stress responses and reproductive hormones. A sample of 204 participants (108 women, 96 men) underwent the TSST, with social support being manipulated. The biological and psychological responses followed patterns previously documented in the literature. Linear mixed-effect models indicated that biological sex moderated the trajectories of RMSSD, testosterone, progesterone, and well-being across the TSST phases. Additionally, cortisol responses were more pronounced in men, particularly those with strong power motives. Participants receiving social support exhibited lower estradiol levels during the TSST recovery phase compared to the control group. These findings suggest that the impacts of social stress are shaped by complex interactions between biological and social factors, which could be considered in tailored stress interventions.

The influence of real-time quantitative feedback and verbal encouragement on adults' performance in maximal and explosive strength and power in bench press exercise

Background

In sports practice, a wide array of verbal and non-verbal stimuli can elicit diverse motivations and performance changes. Therefore, the primary objective of this study was to compare the impact of various stimuli on maximal strength and power in bench press exercises.

Methods

This study involved 48 university students (average age 20.5 ± 2.8 years; body mass 80.1 ± 20 kg; height 174.6 ± 6.7 cm; BMI 26.2 ± 6 kg/m2) who engaged in an 8-week resistance training program. The students were randomly divided into three experimental groups and one control group. The first group received real-time quantitative feedback (RF) on their power output during the bench press exercise, the second group received verbal encouragement (VE) from an instructor, and the third group exercised without any external stimulus (WS). The control group (CG) underwent only pre- and post-measurements. To compare differences in strength parameters among groups a Two-Way Repeated Measures ANOVA was applied.

Results

The results revealed significant improvements in the mean weight for one repetition maximum in the real-time quantitative feedback group (5 kg, 9.76%, p = 0.001, d = 0.529) and the verbal encouragement group (5.42 kg, 11.51%, p = 0.001, d = 1.201). Positive changes were also observed in the mean power at 20 and 30 kg for the RF, VE, and WS groups, but at 40 kg, significant improvement was only seen in the real-time quantitative feedback group (247 W, 31.30%, p = 0.001, d = 1.199).

Conclusion

These findings underscore the effectiveness of selected stimuli in enhancing maximum strength and power during bench press exercises, with real-time quantitative feedback proving to be the most effective stimulus for improving both maximal strength and power.

Lactobacillus rhamnosus Sex-Specifically Attenuates Depressive-like Behavior and Mitigates Metabolic Consequences in Obesity

Background

Patients with diabetes exhibit an increased prevalence for emotional disorders compared with healthy humans, partially due to a shared pathogenesis including hormone resistance and inflammation, which is also linked to intestinal dysbiosis. The preventive intake of probiotic lactobacilli has been shown to improve dysbiosis along with mood and metabolism. Yet, a potential role of Lactobacillus rhamnosus (Lacticaseibacillus rhamnosus 0030) (LR) in improving emotional behavior in established obesity and the underlying mechanisms are unknown.

Methods

Female and male C57BL/6N mice were fed a low-fat diet (10% kcal from fat) or high-fat diet (HFD) (45% kcal from fat) for 6 weeks, followed by daily oral gavage of vehicle or 1 × 108 colony-forming units of LR, and assessment of anxiety- and depressive-like behavior. Cecal microbiota composition was analyzed using 16S ribosomal RNA sequencing, plasma and cerebrospinal fluid were collected for metabolomic analysis, and gene expression of different brain areas was assessed using reverse transcriptase quantitative polymerase chain reaction.

Results

We observed that 12 weeks of HFD feeding induced hyperinsulinemia, which was attenuated by LR application only in female mice. On the contrary, HFD-fed male mice exhibited increased anxiety- and depressive-like behavior, where the latter was specifically attenuated by LR application, which was independent of metabolic changes. Furthermore, LR application restored the HFD-induced decrease of tyrosine hydroxylase, along with normalizing cholecystokinin gene expression in dopaminergic brain regions; both tyrosine hydroxylase and cholecystokinin are involved in signaling pathways impacting emotional disorders.

Conclusions

Our data show that LR attenuates depressive-like behavior after established obesity, with changes in the dopaminergic system in male mice, and mitigates hyperinsulinemia in obese female mice.

Ego-Boosting Hormone: Self-Reported and Blood-Based Testosterone Are Associated With Higher Narcissism

Grandiose narcissism is defined as increased motivation for status and viewing oneself as entitled and superior to others. We hypothesized that these tendencies might be associated with basal levels of testosterone because testosterone is considered the most social hormone-driving dominance and the motivation to achieve social status. We distinguished between two facets of grandiose narcissism: agentic (i.e., the tendency to self-promotion in order to win others' admiration and social influence) and antagonistic (i.e., a reactive strategy used to restore threatened status). In 283 adult men, we examined the association between these facets of narcissism and blood-tested and self-reported testosterone levels. Agentic narcissism-the default narcissistic strategy-was positively associated with both testosterone indicators. Moreover, self-reported and objectively measured testosterone were positively correlated. These findings extend previous work by showing that the facets of narcissism have distinct hormonal underpinnings.

Influence of Food Type on Human Psychological-Behavioral Responses and Crime Reduction

The purpose of this narrative review is to emphasize the importance of food consumption and meal selection on mental health and brain function, including psychological and behavioral reactions such as mood, loving relationships, violence, and criminal activity. Additionally, by being aware of the link between food and mental health, the community can be encouraged to make informed food choices in order to avoid unfavorable outcomes like criminality. Food behaviors are shifting significantly over the world. There are also significant changes in mood, sadness, happiness, and violence, as well as the spread of the variety and severity of mental diseases that lead to violent acts. Food intake and meal selection have evolved over the last ten years as the variety and accessibility of food options have become easier and more diverse. These modifications might have both beneficial and bad consequences. This article examines the relationship between food intake and its impact on marital satisfaction. The goal of this review is to support or refute the claim that food influences mood, love, or criminal behavior, or vice versa. Various diets can have an impact on one's mental health and brain, influencing psychological reactions and behavioral responses such as mood, loving relationships, violence, and even criminal activity. Food insecurity has been demonstrated in various studies to have a negative impact on health and psychological well-being, leading to despair, loss of happiness, marital conflict, and violence. For example, herbal extracts and flavonoids have the potential to improve gut microbiota and treat mood disorders. Understanding how the gut-brain axis communicates might help guide interventions for mood and cognitive function. Since the root of most diseases and behaviors is significantly related to the type of food consumed, this research addresses this issue in order to reduce the cost of treatment and prevention of crime and delinquency at the community level by consciously choosing the food consumed by the society. In other words, prevention is always better than cure.

No Compelling Evidence that Self-Reported Personality Traits Explain Basal Testosterone and Cortisol’s Associations with Status-Relevant Behavior

Objective

A goal of behavioral neuroendocrinology is to understand how basal hormone levels relate to behavior. Studies of human participants sometimes measure self-reported personality traits, in addition to or instead of direct behavioral observation. Although personality traits often predict their respective behaviors, whether personality explains hormone-behavior relationships remains unclear.

Methods

We obtained data from eight previous studies (total N = 985) that examined baseline testosterone and cortisol as predictors of status-relevant behavior (competitiveness, dominance, risk-taking, aggression, affiliation, and social status). We tested whether the previously reported hormone-behavior relationships are mediated by self-reported personality traits (e.g., trait dominance, prestige, extraversion). As a secondary research question, we also tested whether trait dominance moderated the testosterone-behavior relationships.

Results

As expected, self-reported personality traits often predicted status-relevant behaviors, but there was little evidence that traits also correlated with basal testosterone or the testosterone × cortisol interaction. Across all eight studies, personality traits did not significantly mediate hormone-behavior relationships. Indeed, the effect sizes of the hormone-behavior relationships were robust to the inclusion of personality traits as covariates. Further, we did not find strong or consistent evidence that trait dominance moderates the testosterone-behavior association.

Conclusion

Results suggest that basal testosterone and cortisol predict status-related behavior independent of self-reported personality. We discuss how these results may have broader implications for the physiological mechanisms by which testosterone and cortisol influence behavior, a process that could be unconscious and automatic. We also discuss alternative explanations, limitations, and future directions.

Narcissism moderates the association between basal testosterone and generosity in men

Research has linked hormones to behavioral outcomes in intricate ways, often moderated by psychological dispositions. The associations between testosterone and antisocial or prosocial outcomes also depend on dispositions relevant to status and dominance. In two studies (N1 = 68, N2 = 83), we investigated whether endogenous testosterone, measured in saliva, and narcissism, a psychological variable highly relevant to status motivation, interactively predicted men's preferences regarding resource allocation. Narcissism moderated the links between testosterone and social value orientation: among low narcissists testosterone negatively predicted generosity in resource allocation and probability of endorsing a prosocial (vs. pro-self) value orientation, whereas among high narcissists testosterone tended to positively predict generosity and the probability of endorsing a prosocial (vs. pro-self) value orientation. We discuss these results as examples of calibrating effects of testosterone on human behavior, serving to increase and maintain social status. We advocate the relevance of psychological dispositions, alongside situations, when examining the role of T in social outcomes.

The causal effect of testosterone on men's competitive behavior is moderated by basal cortisol and cues to an opponent's status: Evidence for a context-dependent dual-hormone hypothesis

Testosterone has been theorized to direct status-seeking behaviors, including competitive behavior. However, most human studies to date have adopted correlational designs, and findings across studies are inconsistent. This experiment (n = 115) pharmacologically manipulated men's testosterone levels prior to a mixed-gender math competition and examined basal cortisol (a hormone implicated in stress and social avoidance) and context cues related to an opponent's perceived status (an opponent's gender or a win/loss in a prior competition) as factors that may moderate testosterone's impact on competitive behavior. We test and find support for the hypothesis that testosterone given to low-cortisol men evokes status-seeking behavior, whereas testosterone given to high-cortisol men evokes status-loss avoidance. In the initial rounds of competition, testosterone's influence on competitive decisions depended on basal cortisol and opponent gender. After providing opponent-specific win-lose feedback, testosterone's influence on decisions to reenter competitions depended on basal cortisol and this objective cue to status, not gender. Compared to placebo, men given exogenous testosterone who were low in basal cortisol showed an increased tendency to compete against male and high-status opponents relative to female and low-status opponents (status-seeking). Men given exogenous testosterone who were high in basal cortisol showed the opposite pattern-an increased tendency to compete against female and low-status opponents relative to male and high-status opponents (status-loss avoidance). These results provide support for a context-dependent dual-hormone hypothesis: Testosterone flexibly directs men's competitive behavior contingent on basal cortisol levels and cues that signal an opponent's status. (PsycInfo Database Record (c) 2022 APA, all rights reserved).

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.

Enhanced Originality of Ideas in Women During Ovulation: A Within-Subject Design Study

The signaling theory suggests that creativity may have evolved as a signal for mates. Indeed, its aesthetic value might not have been necessary for survival, but it could have helped to attract a mate, fostering childbearing. If we consider creativity as such a signal, we should expect it will be enhanced in the context related to sexual selection. This hypothesis was tested mainly for men. However, both men and women display physical and mental traits that can attract a mate. Previous studies showed that women can be more creative during their peak fertility. We advanced these findings in the present study, applying reliable measures of menstrual cycle phases (examining saliva and urine samples) and the highly recommended within-subject design. We also introduced and tested possible mediators of the effect. We found women’s ideas to be more original during ovulation compared to non-fertile phases of the ovulatory cycle. The results are discussed in the context of signaling theory and alternative explanations are considered.

The powerful self: How social power and gender influence face perception

While ample evidence supports an association between power and dominance, little is still known about how temporary experiences of power influence the way people come to see themselves and others. The present research investigates the effect of social power on self- and other-face recognition, and examines whether gender modulates the direction of this effect. Male and female participants were induced to feel either powerful or powerless and had to recognize their own face and those of same-sex strangers from a series of images ranging from a dominant to a submissive version of the original. Results showed that males more frequently chose a dominant self-image under high power, whereas females selected a submissive self-image under low power. When presented with faces of same-sex targets female participants relied on low-power features (i.e., submissiveness) of the self in the perception of others (assimilation effect), whereas male participants more often selected a dominant image of strangers when feeling powerless (constrast effect). The effects of power did not extend to more deliberate judgments of dominance and likability, suggesting that respective biases in face recollection operated at an implicit level. This research underscores the cognitive and motivational underpinnings of power and related gender gaps in power attainment.

Cortisol and Testosterone in Leadership Practice

This study sought to discover whether and how biological parameters can predict leadership behavior in the following leadership-related tasks: a face-to-face negotiation (Study 1), an individual problem-solving case (Study 2), and a group-based problem-solving case (Study 3). We replicated previous work by Mehta, Mor, Yap and Prasad in testing the dual-hormone hypothesis related to testosterone increase and cortisol decrease (Study 1), but our findings do not provide evidence to support the dual-hormone hypothesis. In Study 2, we found that high openness was a significant predictor in the individual problem-solving case. The results from Study 3 indicated that higher openness was related to a better score on the group exercise. Our findings did not support the dual-hormone model, and we did not find support for the seller-specific effect reported in Mehta et al. The original study included 64 participants with complete hormone data, while our replicational study involved 114 participants with complete hormone data.

Motives and Laterality: Exploring the Links

Objectives

We explored associations between the needs for power, achievement, and affiliation and functional cerebral asymmetries (FCAs), guided by three established hypotheses about the nature of these associations.

Methods

One-hundred-and-seven participants completed picture-story measures of dispositional motives and activity inhibition (AI), a frequent moderator of motive-behavior associations, tasks measuring FCAs (line bisection, chimeric emotional face judgments, turning bias, perceptual and response asymmetries on the Poffenberger task), self-reported laterality preferences (handedness, footedness, ear and eye preference), and interhemispheric interaction (crossed-uncrossed difference). They also completed an experiment manipulating hand contractions (left, right, both, neither) while they worked on a second picture-story motive measure.

Results

Dispositional power motivation was associated with stronger rightward asymmetry and less interhemispheric transfer in high-AI and stronger leftward asymmetry and more interhemispheric transfer in low-AI individuals. For the affiliation motive, findings were fewer and in the opposite direction of those for the power motive. These findings emerged for men, but not for women. Left- or right-hand contractions led to increases in power and achievement motivation, but not affiliation motivation. Only left-hand contractions led to decreased AI.

Conclusions

We discuss these findings in the context of sex-dimorphic organizing and activating effects of steroids on motives and laterality.

Testosterone administration in women increases the size of their peripersonal space

Peripersonal space (PPS) is the space immediately surrounding the body, conceptualised as a sensory-motor interface between body and environment. PPS size differs between individuals and contexts, with intrapersonal traits and states, as well as social factors having a determining role on the size of PPS. Testosterone plays an important role in regulating social-motivational behaviour and is known to enhance dominance motivation in an implicit and unconscious manner. We investigated whether the dominance-enhancing effects of testosterone reflect as changes in the representation of PPS in a within-subjects testosterone administration study in women (N = 19). Participants performed a visuo-tactile integration task in a mixed-reality setup. Results indicated that the administration of testosterone caused a significant enlargement of participants' PPS, suggesting that testosterone caused participants to implicitly appropriate a larger space as their own. These findings suggest that the dominance-enhancing effects of testosterone reflect at the level of sensory-motor processing in PPS.

Leader emergence and affective empathy: A dynamic test of the dual-hormone hypothesis

Personal distress is a building block of empathy, yet has received scant attention in studies of individual differences in leadership. We investigate whether the effect of leader emergence on men's distress is influenced by their personalized power motive (p Power) and changes in their testosterone (T) and cortisol (C) levels. In an experiment involving 96 males, p Power modulated the direction and intensity of T change in emergent leaders, with high p-Power leaders showing a more positive T change compared to their low p-Power counterparts. We also conducted a dynamic test of the dual-hormone hypothesis in which participants' changes in T and C interacted to produce differences in personal distress. Contrary to expectations, positive changes in T were associated with increased distress at negative changes in C. Given that high T and low C are associated with leadership, we explain these findings and question the assumption that personal distress represents a shortcoming in leaders.

Convergent, Discriminant, and Incremental Validity of the Pictorial Attitude Implicit Association Test and the Picture Story Exercise as Measures of the Implicit Power Motive

The Pictorial Attitude Implicit Association Test (PA–IAT) has recently been proposed as new measure of implicit motives. We report a study that provides the first evidence for the convergent validity of the PA–IAT by showing that the PA–IAT correlates significantly with a standard measure of implicit motives [i.e. the Picture Story Exercise (PSE)]. Discriminant validity of the PA–IAT was verified in the sense that the PA–IAT shared virtually no common variance with explicit motive measures. Our analyses revealed that the PA–IAT and PSE can best be conceived as related but distinct measures. We further showed that the PA–IAT had incremental validity in predicting performance on a memory recall task over and above the PSE. In general, our results confirm that the PA–IAT is a valid measure of implicit motives and can serve as valid alternative to the PSE. Copyright © 2012 John Wiley & Sons, Ltd.

Beyond the challenge hypothesis: The emergence of the dual-hormone hypothesis and recommendations for future research

The challenge hypothesis makes specific predictions about the association between testosterone and status-seeking behaviors, but the findings linking testosterone to these behaviors are often inconsistent. The dual-hormone hypothesis was developed to help explain these inconsistencies. Specifically, according to this hypothesis, testosterone's association with status-seeking behavior depends on levels of cortisol. Here, we (1) describe the dual-hormone hypothesis in relation to the challenge hypothesis; (2) review recent studies that tested the dual-hormone hypothesis as well as meta-scientific evidence of heterogeneous dual-hormone findings across studies; (3) discuss potential explanations for this heterogeneity, including methodological considerations, contextual factors, and individual differences; and (4) provide recommendations for new work aimed at testing and extending the dual-hormone hypothesis.

Social withdrawal and testosterone levels in early adolescent boys

Social withdrawal may lead to mental health problems and can have a large impact on a life course, particularly among boys. To support adolescents with social withdrawal, an integrative understanding of the biological bases would be helpful. Social dominance, a possible opposite of social withdrawal, is known to have positive associations with testosterone levels. A previous study suggested that social withdrawal has a negative relationship with sexual maturity among adolescent boys. However, the relationship between social withdrawal and testosterone in adolescence is unknown. This study aimed to examine whether social withdrawal was negatively associated with testosterone levels in early adolescent boys. Salivary samples were collected from 159 healthy early adolescent boys (mean age [standard deviation]: 11.5 [0.73]) selected from participants of the "population-neuroscience study of the Tokyo Teen Cohort" (pn-TTC). Social withdrawal and confounding factors, such as the secondary sexual characteristics and their age in months, were evaluated by self-administered questionnaires completed by the primary parents. The degree of social withdrawal was assessed with the Child Behaviour Checklist (CBCL). Levels of salivary testosterone, and cortisol as a control, were measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Logistic regression was conducted to examine the association between social withdrawal and testosterone levels. A higher risk of social withdrawal was associated with a lower salivary testosterone level after adjustment for age in months (odds ratio 0.55, 95 % confidence interval 0.33-0.94), and the association remained significant after adjusting for body mass index, the degree of anxiety/depression and pubertal stage. Thus, we found a negative relationship between social withdrawal and testosterone levels in early adolescent boys. These findings may help to clarify the biological foundations of and to develop support for social withdrawal.

Salivary cytokines as a biomarker of social stress in a mock rescue mission

Using salivary inflammatory markers as a noninvasive biomonitoring technique within natural social contexts has become increasingly important to link social and biological responses. Many studies have associated circulating cytokines to distinct aspects of physical activity and social/emotional behavior; however, they have not been linked to success and failure in a naturalistic setting for military personnel performing tasks. In this study, salivary cytokines were studied in a group of fifteen Air Force Reserve Officers' Training Corps (ROTC; 14 males, 1 female) subjects performing three mock hostage rescue missions, designed to prompt responses associated with baseline, success, and failure. Each subject completed the tasks of the mission individually and again in randomly assigned teams. Participants were outfitted via direct skin contact with comfortable external Zephyr™ sensors to monitor heart rate, breathing rate, and activity while completing each task. Saliva samples were collected before and after the completion of each mission, and cytokine levels were quantified using enzyme-labelled immunoassay (ELISA) beads. These biomarkers were used to describe the body's immune response to success and failure when performing a mock rescue mission individually and in a team. All measured cytokine levels increased following failed missions performed individually, compared to cytokine levels associated with successful missions. When completing the tasks as a team, there were no significant differences in cytokine response between success and failure; however, being in a team stimulated an increased pre-mission cytokine response, suggesting the concept of teamwork and performing with peers for the first time had a more significant impact than the notion of failing. Additionally, none of the cytokines tested for individual missions correlated to physical activity markers (heart rate, breathing rate, activity) measured during performance. These results indicate a potentially new noninvasive method of determining social stress levels under taxing conditions.

The complex and bidirectional interaction between sex hormones and exercise performance in team sports with emphasis on soccer

A constant topic reported in the lay press is the effect of sex hormones on athletic performance and their abuse by athletes in their effort to enhance their performance or to either boost or sidestep their hard, protracted, and demanding training regimens. However, an issue that it is almost never mentioned is that the athletic training itself affects the endogenous production of androgens and estrogens, while also being affected by them. Among sports, soccer is a particularly demanding activity, soccer players needing to possess high levels of endurance, strength, and both aerobic and anaerobic capacity, with the very great physiological, metabolic, physical, and psychological exertion required of the players being both influenced by sex steroids and, reciprocally, affecting sex steroid levels. This review focuses on the currently available knowledge regarding the complex relationship between athletic training and competition and sex steroid hormone adaptation to the demands of the exercise effort. In the first part of the review, we will examine the effects of endogenous testosterone, estrogen, and adrenal androgens on athletic performance both during training and in competition. In the second part, we will explore the reciprocal effects of exercise on the endogenous sex hormones while briefly discussing the recent data on anabolic androgenic steroid abuse.

Testosterone, Cortisol and Financial Risk-Taking

Both testosterone and cortisol have major actions on financial decision-making closely related to their primary biological functions, reproductive success and response to stress, respectively. Financial risk-taking represents a particular example of strategic decisions made in the context of choice under conditions of uncertainty. Such decisions have multiple components, and this article considers how much we know of how either hormone affects risk-appetite, reward value, information processing and estimation of the costs and benefits of potential success or failure, both personal and social. It also considers how far we can map these actions on neural mechanisms underlying risk appetite and decision-making, with particular reference to areas of the brain concerned in either cognitive or emotional functions.

The Effect of Testosterone Administration and Digit Ratio (2D:4D) on Implicit Preference for Status Goods in Healthy Males

Testosterone has been linked to social status seeking in humans. The present study investigated the effects of testosterone administration on implicit and explicit preferences for status goods in healthy male participants (n = 64), using a double-blind, placebo-controlled, between-subjects design. We also investigated the interactive effect between second-to-fourth digit ratio (2D:4D; i.e., a proximal index of prenatal testosterone) and testosterone treatment on status preferences. Results showed that testosterone administration has no discernable influence on self-reported willingness-to-pay (i.e., the explicit measure) or implicit attitudes towards status goods. Individuals with lower 2D:4D (i.e., more masculine) had more positive attitudes for high-status goods on an Implicit Association Task, and this association was abolished with testosterone administration. These data suggest interactive effects of acute testosterone administration and prenatal testosterone exposure on human social status seeking, and highlight the utility of implicit methods for measuring status-related behavior.

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.

Winners, losers, and posers: The effect of power poses on testosterone and risk-taking following competition

A contribution to a special issue on Hormones and Human Competition. The effect of postural power displays (i.e. power poses) on hormone levels and decision-making has recently been challenged. While Carney et al. (2010) found that holding brief postural displays of power leads to increased testosterone, decreased cortisol and greater economic risk taking, this failed to replicate in a recent high-powered study (Ranehill et al. 2015). It has been put forward that subtle differences in social context may account for the differences in results. Power displays naturally occur within the context of competitions, as do changes in hormones, and researchers have yet to examine the effects of poses within this ecologically relevant context. Using a large sample of 247 male participants, natural winners and losers of a physical competition were randomly assigned to hold a low, neutral or high-power postural display. We found no main effect of pose type on testosterone, cortisol, risk or feelings of power. Winners assigned to a high-power pose had a relative, albeit small, rise in testosterone compared to winners who held neutral or low-power poses. For losers, we found little evidence that high-power poses lead to increased testosterone relative to those holding neutral or low-powered poses. If anything, the reverse was observed - losers had a reduction in testosterone after holding high-power poses. To the extent that changes in testosterone modulate social behaviors adaptively, it is possible that the relative reduction in testosterone observed in losers taking high-powered poses is designed to inhibit further "winner-like" behavior that could result in continued defeat and harm. Still, effects were small, multiple comparisons were made, and the results ran counter to our predictions. We thus treat these conclusions as preliminary.

Testosterone and androgen receptor gene polymorphism are associated with confidence and competitiveness in men

A contribution to a special issue on Hormones and Human Competition. Studies in non-human animals and humans have demonstrated the important role of testosterone in competitive interactions. Here, we investigated whether endogenous testosterone levels predict the decision to compete, in a design excluding spite as a motive underlying competitiveness. In a laboratory experiment with real monetary incentives, 181 men solved arithmetic problems, first under a noncompetitive piece rate, followed by a competition incentive scheme. We also assessed several parameters relevant to competition, such as risk taking, performance, and confidence in one's own performance. Salivary testosterone levels were measured before and 20min after the competition task using mass spectrometry. Participants were also genotyped for the CAG repeat polymorphism of the androgen receptor gene, known to influence the efficacy of testosterone signaling in a reciprocal relationship to the number of CAG repeats. We observed a significant positive association between basal testosterone levels and the decision to compete, and that higher testosterone levels were related to greater confidence in one's own performance. Whereas the number of CAG repeats was not associated with the choice to compete, a lower number of CAG repeats was related to greater confidence in those who chose to compete, but this effect was attributable to the polymorphism's effect on actual performance. An increase in testosterone levels was observed following the experiment, and this increase varied with self-reported high-school math grades. We expand upon the latest research by documenting effects of the androgen system in confidence in one's own ability, and conclude that testosterone promotes competitiveness without spite.

The role of testosterone and estrogen in consumer behavior and social & economic decision making: A review

A contribution to a special issue on Hormones and Human Competition.This manuscript reviews the current literature on the actions of the steroid hormones testosterone and estradiol in shaping humans' behavior within two applied contexts, specifically consumer behavior and decision making (both social and economic). The theoretical argument put forth is that steroids shape these everyday behaviors and choices in service to being more competitive in achieving long-term goals related to resource acquisition, mating success, and social dominance. In addition, a discussion of the increased research focus on the role of steroids in other applied business domains will highlight the relevant applications of basic science discoveries in behavioral endocrinology.

Testosterone and reproductive effort in male primates

Considerable evidence suggests that the steroid hormone testosterone mediates major life-history trade-offs in vertebrates, promoting mating effort at the expense of parenting effort or survival. Observations from a range of wild primates support the "Challenge Hypothesis," which posits that variation in male testosterone is more closely associated with aggressive mating competition than with reproductive physiology. In both seasonally and non-seasonally breeding species, males increase testosterone production primarily when competing for fecund females. In species where males compete to maintain long-term access to females, testosterone increases when males are threatened with losing access to females, rather than during mating periods. And when male status is linked to mating success, and dependent on aggression, high-ranking males normally maintain higher testosterone levels than subordinates, particularly when dominance hierarchies are unstable. Trade-offs between parenting effort and mating effort appear to be weak in most primates, because direct investment in the form of infant transport and provisioning is rare. Instead, infant protection is the primary form of paternal investment in the order. Testosterone does not inhibit this form of investment, which relies on male aggression. Testosterone has a wide range of effects in primates that plausibly function to support male competitive behavior. These include psychological effects related to dominance striving, analgesic effects, and effects on the development and maintenance of the armaments and adornments that males employ in mating competition.

ALL OUR SONS: THE DEVELOPMENTAL NEUROBIOLOGY AND NEUROENDOCRINOLOGY OF BOYS AT RISK

Why are boys at risk? To address this question, I use the perspective of regulation theory to offer a model of the deeper psychoneurobiological mechanisms that underlie the vulnerability of the developing male. The central thesis of this work dictates that significant gender differences are seen between male and female social and emotional functions in the earliest stages of development, and that these result from not only differences in sex hormones and social experiences but also in rates of male and female brain maturation, specifically in the early developing right brain. I present interdisciplinary research which indicates that the stress-regulating circuits of the male brain mature more slowly than those of the female in the prenatal, perinatal, and postnatal critical periods, and that this differential structural maturation is reflected in normal gender differences in right-brain attachment functions. Due to this maturational delay, developing males also are more vulnerable over a longer period of time to stressors in the social environment (attachment trauma) and toxins in the physical environment (endocrine disruptors) that negatively impact right-brain development. In terms of differences in gender-related psychopathology, I describe the early developmental neuroendocrinological and neurobiological mechanisms that are involved in the increased vulnerability of males to autism, early onset schizophrenia, attention deficit hyperactivity disorder, and conduct disorders as well as the epigenetic mechanisms that can account for the recent widespread increase of these disorders in U.S. culture. I also offer a clinical formulation of early assessments of boys at risk, discuss the impact of early childcare on male psychopathogenesis, and end with a neurobiological model of optimal adult male socioemotional functions.

Effects of two dominance manipulations on the stress response: Cognitive and embodied influences

In response to stress, physiological and mental resources are allocated towards those systems that are needed for rapid responding in terms of fight or flight. On the other hand, long term regenerative processes such as growth, digestion and reproduction are attenuated. Levels of the sex steroid testosterone are reduced in participants that suffer from chronic stress. However, beyond its role for reproductive functions, testosterone plays an important role in the regulation of social status and dominance, testosterone levels increase during competition or when the social status is challenged. The Trier Social Stress Test (TSST), a laboratory stressor with a substantial social-evaluative component, can provoke an increase in salivary testosterone levels. Still, so far the reported findings regarding acute stress effects on testosterone are equivocal, possibly due to moderating effects. In this study we experimentally manipulated social dominance in 56 healthy participants (28m) by two independent manipulations (body posture and cognitive role taking) and subjected them to the TSST. We analyzed salivary testosterone and cortisol levels as dependent measures for the endocrine stress response. The role taking manipulation interacted with the testosterone response: we found the strongest increase when participants had to put themselves in a dominant (vs. submissive) role. Our results suggest that transient changes in testosterone levels during stress reflect a response to status threat that is affected by social dominance.

Testosterone, cortisol, and human competition

Testosterone and cortisol figure prominently in the research literature having to do with human competition. In this review, we track the history of this literature, concentrating particularly on major theoretical and empirical contributions, and provide commentary on what we see as important unresolved issues. In men and women, athletic competition is typically associated with an increase in testosterone (T) and cortisol (C). Hormone changes in response to non-athletic competition are less predictable. Person (e.g., power motivation, mood, aggressiveness, social anxiety, sex, and baseline levels of T and C) and context (e.g., whether a competition is won or lost, the closeness of the competition, whether the outcome is perceived as being influenced by ability vs. chance, provocations) factors can influence hormone responses to competition. From early on, studies pointed to a positive relationship between T and dominance motivation/status striving. Recent research, however, suggests that this relationship only holds for individuals with low levels of C - this is the core idea of the dual-hormone hypothesis, and it is certain that the broadest applications of the hypothesis have not yet been realized. Individuals differ with respect to the extent to which they embrace competition, but the hormonal correlates of competitiveness remain largely unexplored. Although rapid increases in both T and C associated with competition are likely adaptive, we still know very little about the psychological benefits of these hormonal changes. Administration studies have and will continue to contribute to this inquiry. We close with a discussion of what, we think, are important methodological and mechanistic issues for future research.

Exogenous testosterone increases men's perceptions of their own physical dominance

Men's testosterone is associated with several constructs that are linked to dominance rank, such as risk-taking, mating success, and aggression. However, no study has directly tested the relationship between men's self-perceived dominance and testosterone using an experimental design. We employed a within-subjects, double-blind, placebo-controlled paradigm to assess whether testosterone influences men's self-perceived dominance. Exogenous testosterone or a placebo was administered to healthy adult men and self-perceptions of physical dominance were subsequently assessed by having participants select what they believed to be their true face from an array of images digitally manipulated in masculinity. Men picked a more masculine version of their own face after testosterone versus placebo--an effect that was particularly pronounced among men with relatively low baseline testosterone. These findings indicate that a single administration of testosterone can rapidly modulate men's perceptions of their own physical dominance, which may explain links between testosterone and dominance-related behaviors.

The Influence of Facial Characteristics on the Relation between Male 2D:4D and Dominance

Although relations between 2D:4D and dominance rank in both baboons and rhesus macaques have been observed, evidence in humans is mixed. Whereas behavioral patterns in humans have been discovered that are consistent with these animal findings, the evidence for a relation between dominance and 2D:4D is weak or inconsistent. The present study provides experimental evidence that male 2D:4D is related to dominance after (fictitious) male-male interaction when the other man has a dominant, but not a submissive or neutral face. This finding provides evidence that the relationship between 2D:4D and dominance emerges in particular, predictable situations and that merely dominant facial characteristics of another person are enough to activate supposed relationships between 2D:4D and dominance.

Salivary Testosterone Is Consistently and Positively Associated with Extraversion: Results from The Netherlands Study of Depression and Anxiety

BACKGROUND

Testosterone has been postulated as a 'social' hormone, but the relationship between testosterone and personality traits linked with socially oriented behaviors such as extraversion remains unclear. The objective of our study was to investigate the association between baseline salivary testosterone levels and the Big Five personality traits.

METHODS

We studied the relationship between salivary testosterone (morning and evening) and NEO-FFI (Five-Factor Inventory) personality traits in 1,611 participants with lifetime or current depression and/or anxiety and 482 participants without depression/anxiety of the Netherlands Study of Depression and Anxiety (NESDA).

RESULTS

The personality domain of extraversion was independently associated with higher salivary testosterone, both in healthy subjects (β = 0.094; p = 0.04) and in subjects with lifetime or current depression and/or anxiety (β = 0.092; p < 0.001). In multivariable adjusted analyses, extraversion remained the only personality trait that was positively associated with salivary testosterone (β = 0.079; p = 0.006).

CONCLUSION

We conclude that salivary testosterone is consistently and positively related to extraversion, supporting the notion of a hormonal basis of this personality trait, which may be linked to the tendency to strive for and maintain social status. © 2015 S. Karger AG, Basel.