Winning, losing, mood, and testosterone.

In two experiments, male college students either won or lost $5 on a task controlled entirely by chance. In both studies, winners reported a more positive mood change than did losers and, in Experiment 2, winners reported a more positive mood change than a neutral group that did not win or lose money. After the task was completed, winners exhibited significantly higher testosterone levels than losers. Levels of cortisol, a hormone associated with stress and arousal, did not differ among the groups, suggesting that a hormone-behavior response pattern for winning and losing is specific to testosterone. These data suggest that winning can alter testosterone levels in men and that mood may mediate such changes.     

Causal attribution and psychobiological response to competition in young men

A contribution to a special issue on Hormones and Human Competition.Psychoneuroendocrine effects of competition have been widely accepted as a clear example of the relationship between androgens and aggressive/dominant behavior in humans. However, results about the effects of competitive outcomes are quite heterogeneous, suggesting that personal and contextual factors play a moderating role in this relationship. To further explore these dimensions, we aimed to examine (i) the effect of competition and its outcome on the psychobiological response to a laboratory competition in young men, and (ii) the moderating role of some cognitive dimensions such as causal attributions. To do so, we compared the responses of 56 healthy young men faced with two competitive tasks with different instructions. Twenty-eight men carried out a task whose instructions led subjects to think the outcome was due to their personal performance (“merit” task), whereas 28 other men faced a task whose outcome was attributable to luck (“chance” task). In both cases, outcome was manipulated by the experimenter. Salivary steroid hormones (testosterone and cortisol), cardiovascular variables (heart rate and blood pressure), and emotional state (mood and anxiety) were measured at different moments before, during and after both tasks. Our results did not support the “winner-loser effect” because no significant differences were found in the responses of winners and losers. However, significantly higher values on the testosterone and cardiovascular variables, along with slight decreases in positive mood, were associated with the merit-based competition, but not the chance-based condition. In addition, an exploratory factorial analysis grouped the response components into two patterns traditionally related to more active or more passive behaviors. Thus, our results suggest that the perception of contributing to the outcome is relevant in the psychobiological response to competition in men. Overall, our results reveal the importance of the appraisal of control and causal attribution in understanding human competitive interactions.     

Hormonal and behavioral responses of starlings during a confrontation with males or females at nest boxes during the reproductive season

We investigated in an aviary experiment the behavioral and hormonal responses of European starlings (Sturnus vulgaris) that were moved from a same sex group to an aviary containing either a nest box alone, a nest box and another male, or a nest box and a female. Luteinizing hormone (LH) and testosterone (T) levels increased significantly and independently of the situation, suggesting that nest boxes were the most important stimulus affecting the levels of these hormones. Some birds occupied more than two boxes (winners), and others a single or no box (losers). Levels of T increased less in males that did not acquire a nest box. However, the increase in LH was similar in all males after the test. Singing was positively correlated with T levels. Winners started singing earlier and sang more during a contest than losers. In the presence of females LH increased more in winners than in losers, while the increase in T was similar in both groups. In females, there was no increase in T but LH increased in the presence of males. Levels were higher in females paired with winners than in females paired with losers. Finally, winners advertised their nest boxes more frequently than losers. These results indicate that within a relatively short time frame levels of LH and T increase following the transfer from a flock to a territorial situation and can react independently from each other depending on reproductive circumstances. For males, the possession of a nest box and, for females, the qualities of the male seemed to be the most important factors stimulating reproduction.     

Sex difference in testosterone response to a video game contest

Testosterone (T) and cortisol (C) were assayed from saliva samples given by young men (n = 28) and women (n = 32) before, during, and after competing with a same-sex partner in a video game. The T response to the competition is different in each sex; the C response is the same. Male results confirm prior reports of a precontest rise in testosterone. Male results did not confirm previous findings that, after a contest, the testosterone of winners is higher than that of losers, perhaps because the video game contest produced little mood difference between male winners and losers. Unlike male testosterone, female testosterone generally decreased throughout the experiment. Trends in T and C are parallel in women but not in men. Apparently T works differently in competition between men than between women.     

Reciprocity between endocrine state and contest behavior in the killifish, Kryptolebias marmoratus

Given the dramatic behavioral effects of winning and losing contests, and pronounced changes in stress and sex steroid hormones post-fight, it is reasonable to suppose that these hormones also dictate future behavior. We sampled water-borne cortisol, testosterone (T), and 11-ketotestosterone (KT) before and after contests in the mangrove killifish, Kryptolebias marmoratus, to determine how endogenous steroid hormone levels might predict and respond to contest dynamics or success. Pre-fight cortisol related negatively, and pre-fight T related positively to contest initiation and winning, particularly in the smaller opponent. In the pairs where a larger fish won the contest, winners with higher pre-fight T and lower pre-fight cortisol delivered more attacks to the losers. Contest duration and escalation influenced post-fight hormone concentrations primarily in losers. Escalation significantly increased post-fight cortisol, T, and KT for losers but not for winners. However, winners that attacked losers at higher rates had higher levels of post-fight cortisol. Losers also demonstrate the most consistent post-fight hormone responses, particularly to contest escalation and duration. Despite the bidirectional relationship between hormones and contest behavior, we found no overall mean differences in pre- or post-fight cortisol, T, or KT between eventual winners and losers. Thus, it is evident that the categorical states of winner and loser cannot alone reveal the complex, reciprocal associations between endocrine systems and social behavior.     

Competition-related testosterone,cortisol, and perceived personal success in recreational women athletes

Thirty-five women participating in one or more intramural flag-football games provided saliva samples before, immediately after, and 10 min after competition and completed an after-competition questionnaire appraising their own performance during the game. As seen in other studies of elite athletes, these recreational athletes, on average, showed significant elevations in testosterone (T) and cortisol (C) across the competition period – the “competition effect”. In winners and losers, T levels at all time points measured were positively related to athletes' appraisals of their own individual performance. Results from this study show that the competition effect for T and C is evident in recreational women athletes and provide preliminary evidence about the relationship between cognitive appraisal and competition-related T levels.     

Immunocompetence and resource holding potential in the damselfly, Calopteryx virgo L

It is generally believed that resource holding potential reliablyreflects male quality, but empirical evidence showing this isscarce. Here we show that the outcome of male-male competitionmay predict male immunocompetence in the territorial damselfly,Calopteryx virgo (Odonata: Calopterygidae). We staged contestsbetween 27 pairs of males and found that winners of the contestsshowed higher immunocompetence, measured as encapsulation response,compared with that of losers. Furthermore, the winners had largerfat reserves. We also collected 29 males that had not been usedin staged contests, and found that in these males encapsulationresponse correlated positively with an individual's fat reserves.Both immunocompetence and resource holding potential seem todepend on energy reserves, suggesting a trade-off between parasiteresistance and energetically costly territorial behavior. Theresults suggest that the outcome of male-male contest can beused to predict male quality in terms of immune defense.     

Modifying effect of the repeated experience of agonistic confrontations on effect of naltrexone in male mice

In mice with different experience of agonistic confrontations: victories or social defeats during 3 and 10 days (T3 and T10 winners and T3 and T10 losers, resp.), T10 winners displayed a lesser aggression and a more hostile behaviour than T3 winners. Naltrexone dose-dependently decreased attacks in the T3 winners and did not affect aggressive grooming, diggings, autogrooming, and exploratory activity. Naltrexone was ineffective in T10 winners. The naltrexone effects were similar in T3 and T10 losers and its high and low doses contrarily affected different parameters of submissive behaviour. The repeated experience of agonistic confrontations seems to modify the naltrexone effects depending on a neurochemical background, differing in winners and losers.     

Relationships between competitive wrestling success and neuroendocrine responses

Previous research on wrestling suggests winning wrestlers will have a greater increase in testosterone (Tes) than losing wrestlers, although the physiological mechanism is unknown. To determine the role of the sympathetic nervous system in this phenomenon, 12 male wrestlers from an National Collegiate Athletic Association Division I program wrestled 5 matches over a 2-day period. Serum samples were collected pre (Pre) and immediately postmatch (Post) for the determination of Tes, cortisol (Cort), Tes/Cort, and epinephrine (Epi). The subjects had a combined record of 34 wins, 31 losses, and 4 ties. Testosterone increased (p < 0.05) for both winners and losers, but the increase was greater for winners (X ± SE; nmol · L(-1); winners, pre = 16.4 ± 1.2, post = 23.2 ± 1.5; losers, pre = 14.8 ± 1.0, post = 19.4 ± 1.2). Cortisol and Epi increased similarly for both winners and losers, whereas the Tes/Cort ratio was unaltered at any time. Relative changes in the Epi response (%Δ) for losers were correlated to %ΔTes (r = 0.91), whereas winners did not exhibit similar relationships (r = 0.09). These data suggest that winning wrestlers may use a different regulatory mechanism for their acute Tes responses than losers who appear to depend on sympathetic regulation. Additionally, these data from humans support the biosocial theory of status and the challenge hypothesis developed for competing males in other species.     

Basal and dynamic relationships between implicit power motivation and estradiol in women

This study investigated basal and reciprocal relationships between implicit power motivation (n Power), a preference for having impact and dominance over others, and both salivary estradiol and testosterone in women. 49 participants completed the Picture Story Exercise, a measure of n Power. During a laboratory contest, participants competed in pairs on a cognitive task and contest outcome (win vs. loss) was experimentally varied. Estradiol and testosterone levels were determined in saliva samples collected at baseline and several times post-contest, including 1 day post-contest. n Power was positively associated with basal estradiol concentrations. The positive correlation between n Power and basal estradiol was stronger in single women, women not taking oral contraceptives, or in women with low-CV estradiol samples than in the overall sample of women. Women's estradiol responses to a dominance contest were influenced by the interaction of n Power and contest outcome: estradiol increased in power-motivated winners but decreased in power-motivated losers. For power-motivated winners, elevated levels of estradiol were still present the day after the contest. Lastly, n Power and estradiol did not correlate with self-reported dominance and correlated negatively with self-reported aggression. Self-reported dominance and aggression did not predict estradiol changes as a function of contest outcome. Overall, n Power did not predict basal testosterone levels or testosterone changes as a function of dominance contest outcome.     

Basal and dynamic relationships between implicit power motivation and estradiol in women

This study investigated basal and reciprocal relationships between implicit power motivation (n Power), a preference for having impact and dominance over others, and both salivary estradiol and testosterone in women. 49 participants completed the Picture Story Exercise, a measure of n Power. During a laboratory contest, participants competed in pairs on a cognitive task and contest outcome (win vs. loss) was experimentally varied. Estradiol and testosterone levels were determined in saliva samples collected at baseline and several times post-contest, including 1 day post-contest. n Power was positively associated with basal estradiol concentrations. The positive correlation between n Power and basal estradiol was stronger in single women, women not taking oral contraceptives, or in women with low-CV estradiol samples than in the overall sample of women. Women's estradiol responses to a dominance contest were influenced by the interaction of n Power and contest outcome: estradiol increased in power-motivated winners but decreased in power-motivated losers. For power-motivated winners, elevated levels of estradiol were still present the day after the contest. Lastly, n Power and estradiol did not correlate with self-reported dominance and correlated negatively with self-reported aggression. Self-reported dominance and aggression did not predict estradiol changes as a function of contest outcome. Overall, n Power did not predict basal testosterone levels or testosterone changes as a function of dominance contest outcome.     

The effects of competition and implicit power motive on men's testosterone,emotion recognition,and aggression

A contribution to a special issue on Hormones and Human Competition.We investigated the effects of competition on men's testosterone levels and assessed whether androgen reactivity was associated with subsequent emotion recognition and reactive and proactive aggression. We also explored whether personalized power (p Power) moderated these relationships. In Study 1, 84 males competed on a number tracing task and interpreted emotions from facial expressions. In Study 2, 72 males competed on the same task and were assessed on proactive and reactive aggression. In both studies, contrary to the biosocial model of status (Mazur, 1985), winners' testosterone levels decreased significantly while losers' levels increased, albeit not significantly. Personalized power moderated the effect of competition outcome on testosterone change in both studies. Using the aggregate sample, we found that the effect of decreased testosterone levels among winners (compared to losers) was significant for individuals low in p Power but not for those with medium or high p Power. Testosterone change was positively related to emotion recognition, but unrelated to either aggression subtype. The testosterone-mediated relationship between winning and losing and emotion recognition was moderated by p Power. In addition, p Power moderated the direct (i.e., non-testosterone mediated) path between competition outcome and emotion recognition and both types of aggression: high p-Power winners were more accurate at deciphering others' emotions than high p-Power losers. Finally, among high p-Power men, winners aggressed more proactively than losers, whereas losers aggressed more reactively than winners. Collectively, these studies highlight the importance of implicit power motivation in modulating hormonal, cognitive, and behavioral outcomes arising from human competition.     

Agonistic behaviour and endogenous plasma hormones in male Japanese quail

Agonistic relationships established among male Japanese quail (Coturnix coturnix) in shortterm dyadic encounters of a round-robin tournament were stable and appeared to be maintained by a form of recognition. The aggressive or submissive behaviour displayed by competitors throughout the tournament did not relate to their circulating levels of luteinizing hormone, androstenedione, 5 α-dihydrotestosterone or corticosterone. However, plasma levels of testosterone were correlated with fighting success in the early phases of the tournament, before agonistic associations were defined. Once relationships stabilized, levels of plasma testosterone in winners declined to values comparable with those of the losers and the qualitatively distinct displays observed in winners or losers were no longer correlated with plasma levels of testosterone. In light of other work, these data suggest that androgens, primarily testosterone, influence the aggressiveness of an individual in initial encounters, helping in turn to determine dominance relationships between opponents. Thereafter, other factors such as learned response biases take precedence. The maintenance of stable social relationships appears to be independent of circulating levels of testosterone in adult male Japanese quail.     

Testosterone,status, and mood in human males

Experimental literature on nonhuman primates indicates that a male's testosterone level changes when his status changes, rising when he achieves or defends a dominant position, and falling when he is dominated. Three experiments are reported which test for a similar effect among adult human males. In the first experiment, subjects played in doubles tennis matches in which winners received prizes of $ 100 apiece. Most winners of matches who had decisive victories showed subsequent rises in testosterone relative to losers of these matches; however, the winners of one very close match, in which there was no clear cut triumph, did not show testosterone rises. In the second experiment, subjects won $100 prizes, or not, depending on the random draw of a lottery. Winners in this situation, where their fortunes came without any effort of their own, did not show subsequent testosterone rises which were greater than those of losers. The third experiment used the natural setting of a medical school graduation. Rises in testosterone were observed among new recipients of the M.D. degree 1 and 2 days after the ceremony. In these experiments, changes in testosterone showed some relationship to subjects' moods. These results suggest that when a man achieves a rise in status through his own efforts, and he has an elation of mood over the achievement, then he is likely to have a rise in testosterone.     

Plasma concentrations of sex steroids and fighting in male Tilapia zillii

In laboratory-held Tilapia zillii the gonadosomatic index ( I _G) is an accurate predictor of dominance in pairwise fights between males. Immediately after fighting no differences were detected between winners, losers or controls, in plasma concentrations of testosterone (T) or 11-ketotestosterone (11KT). 11KT was correlated negatively with I _G and positively with T. 11KT appeared to be the major androgen in this species, but there was no evidence that simple differences in levels of these sex steroids mediated aggressive behaviour.     

Is boldness a resource-holding potential trait? Fighting prowess and changes in startle response in the sea anemone,Actinia equina

Contest theory predicts the evolution of a stable mixture of different strategies for fighting. Here, we investigate the possibility that stable between-individual differences in startle-response durations influence fighting ability or 'resource-holding potential' (RHP) in the beadlet sea anemone, Actinia equina. Both winners and losers showed significant repeatability of pre-fight startle-response durations but mean pre-fight startle-response durations were greater for eventual losers than for eventual winners, indicating that RHP varies with boldness. In particular, individuals with short startle responses inflicted more attacks on their opponent. Both repeatability and mean-level responses were changed by the experience of fighting, and these changes varied with outcome. In losers, repeatability was disrupted to a greater extent and the mean startle-response durations were subject to a greater increase than in winners. Thus, following a fight, this behavioural correlate of RHP behaves in a way similar to post-fight changes in physiological status, which can also vary between winners and losers. Understanding the links between aggression and boldness therefore has the potential to enhance our understanding of both the evolution of animal personality and the 'winner and loser effects' of post-fight changes in RHP.     

Demonstration of Strength and Concealment of Weakness in Escalating Fights of Male Swordtails (Xiphophorus helleri)

In the green swordtail (Xiphophorus helleri) confrontations between strange males regularly escalate to high levels of mutual Bites and Fin Grips, even between males differing greatly in size. The original expectation of early game theory models that the behaviours of the ultimate winners and losers are indistinguishable until shortly before the end of the fight could not be confirmed. A significant characteristic of loser behaviour is that the Biting rates are higher before and after escalation. Conversely, Fin Grips are more frequent in the ultimate winners than the losers. However, such behavioural differences are very poor predictors of the outcome of the fight from the viewpoint of a single fighting individual during the contest. Correct forecasts did not exceed 67%. The escalating fights of swordtails are considered as trials of strength in which the stronger male tries to demonstrate strength by the most costly behaviour pattern available, namely Fin Grips, and the weaker male conceals weakness quite successfully by countering with the same tactic and suppressing signs of weakness such as Avoidance behaviour.     

Testosterone, and winning and losing in human competition

Testosterone and cortisol were measured in six university tennis players across six matches during their varsity season. Testosterone rose just before most matches, and players with the highest prematch testosterone had the most positive improvement in mood before their matches. After matches, mean testosterone rose for winners relative to losers, especially for winners with very positive moods after their victories and who evaluated their own performance highly. Winners with rising testosterone had higher testosterone before their next match, in contrast to losers with falling testosterone, who had lower testosterone before their next match. Cortisol was not related to winning or losing, but it was related to seed (top players having low cortisol), and cortisol generally declined as the season progressed. These results are consistent with a biosocial theory of status.     

Testosterone dynamics during encounter: role of emotional factors

This study attempts to develop a new theory to explain the varying dynamics of testosterone levels in dominant (winners) and subordinate (losers) males, both pre- and post-encounter. The crux of our new theory consists of the following four theses: (1) the strengthening of testosterone synthesis is a result of not only the existence of challenges, but also of a positive mood before an encounter that is associated with the anticipation of a victory; (2) in situations where the anticipation of victory is present but the positive mood is absent, no rise in testosterone levels will occur; (3) testosterone acts as a "pleasure" hormone and usually releases in situations where the individual achieves or anticipates possible satisfaction; (4) an increased release of testosterone to the blood not only decreases anxiety but also elevates the mood, which increases animal's/human's assertiveness and consequently aggressiveness.     

Assessment Strategies and the Effects of Fighting Experience on Future Contest Performance in the Green Anole (Anolis carolinensis)

Social experiences can be useful sources of information for animals charged with making fitness‐related decisions. Fighting experience can alter an animal's perception of its fighting ability possibly leading to changes in future contest decisions, which may increase/decrease their probability of winning future contests. Winner and loser effects have been revealed in a wide array of animals, but studies using reptilian models are rare. This study investigated the impact of fighting experience on future contest performance and outcome in the green anole lizard and investigated the assessment strategies used by anoles during contests of different intensities. To determine whether the green anole expresses winner or loser effects, focal animals engaged in a primary contest with a smaller (larger) opponent to gain a winning (losing) experience; opponent size asymmetries were a significant predictor of contest outcome. Focal individuals were isolated for 2 d before being given a secondary contest with a size‐matched, naïve opponent. We found no evidence of winner or loser effects 2 d following a previous contest. Although previous contest outcome did not dictate future contest success, dynamics of the previous contest did. Highly aggressive primary contest losers won a significant proportion of the secondary contests, while less aggressive losers were more apt to lose the secondary contest. Secondary contest success of prior winners was not influenced by earlier contest performance. Further analyses of contest dynamics reveal that individuals may use different assessment strategies depending on the intensity of the contest. Our results demonstrate that future contest success may be driven more by individual performance in a prior contest and less by prior contest outcome.