Die Wirkung von Testosteron

Der englische Wikipedia Artikel zu Testosteron gibt einen guten Überblick über die durch Testosteron bewirkten Effekte:

In general, androgens such as testosterone promote protein synthesis and thus growth of tissues with androgen receptors.[11]Testosterone can be described as having virilising and anabolic effects (though these categorical descriptions are somewhat arbitrary, as there is a great deal of mutual overlap between them).[12]

Testosterone effects can also be classified by the age of usual occurrence. For postnataleffects in both males and females, these are mostly dependent on the levels and duration of circulating free testosterone.

Before birth

Effects before birth are divided into two categories, classified in relation to the stages of development.

The first period occurs between 4 and 6 weeks of the gestation. Examples include genital virilisation such as midline fusion, phallic urethrascrotal thinning and rugation, and phallic enlargement; although the role of testosterone is far smaller than that of dihydrotestosterone. There is also development of the prostate gland and seminal vesicles.

During the second trimester, androgen level is associated with sex formation.[13] This period affects the femininization or masculinization of the fetus and can be a better predictor of feminine or masculine behaviours such as sex typed behaviour than an adult’s own levels. A mother’s testosterone level during pregnancy is correlated with her daughter’s sex-typical behavior as an adult, and the correlation is even stronger than with the daughter’s own adult testosterone level.[14]

Early infancy

Early infancy androgen effects are the least understood. In the first weeks of life for male infants, testosterone levels rise. The levels remain in a pubertal range for a few months, but usually reach the barely detectable levels of childhood by 4–7 months of age.[15][16] The function of this rise in humans is unknown. It has been theorized that brain masculinizationis occurring since no significant changes have been identified in other parts of the body.[17]The male brain is masculinized by the aromatization of testosterone into estrogen, which crosses the blood–brain barrier and enters the male brain, whereas female fetuses have α-fetoprotein, which binds the estrogen so that female brains are not affected.[18]

Before puberty

Before puberty effects of rising androgen levels occur in both boys and girls. These include adult-type body odor, increased oiliness of skin and hair, acnepubarche(appearance of pubic hair), axillary hair(armpit hair), growth spurt, accelerated bone maturation, and facial hair.[19]

Pubertal

Pubertal effects begin to occur when androgen has been higher than normal adult female levels for months or years. In males, these are usual late pubertal effects, and occur in women after prolonged periods of heightened levels of free testosterone in the blood. The effects include:[19][20]

Growth of spermatogenic tissue in testicles, male fertilitypenis or clitoris enlargement, increased libido and frequency of erection or clitoral engorgement. Growth of jaw, brow, chin, nose, and remodeling of facial bone contours, in conjunction with human growth hormone.[21] Completion of bone maturation and termination of growth. This occurs indirectly via estradiol metabolites and hence more gradually in men than women. Increased muscle strength and mass, shoulders become broader and rib cage expands, deepening of voice, growth of the Adam’s apple. Enlargement of sebaceous glands. This might cause acne, subcutaneous fat in face decreases. Pubic hair extends to thighs and up toward umbilicus, development of facial hair (sideburnsbeardmoustache), loss of scalp hair (androgenetic alopecia), increase in chest hair, periareolar hair, perianal hair, leg hairarmpit hair.

Adult

Testosterone is necessary for normal spermdevelopment. It activates genes in Sertoli cells, which promote differentiation of spermatogonia. It regulates acute HPA (hypothalamic–pituitary–adrenal axis) response under dominance challenge.[22]Androgen including testosterone enhances muscle growth. Testosterone also regulates the population of thromboxane A2 receptors on megakaryocytes and platelets and hence platelet aggregation in humans.[23][24]

Adult testosterone effects are more clearly demonstrable in males than in females, but are likely important to both sexes. Some of these effects may decline as testosterone levels might decrease in the later decades of adult life.[25]

Health risksEdit

Testosterone does not appear to increase the risk of developing prostate cancer. In people who have undergone testosterone deprivation therapy, testosterone increases beyond the castrate level have been shown to increase the rate of spread of an existing prostate cancer.[26][27][28]

Conflicting results have been obtained concerning the importance of testosterone in maintaining cardiovascular health.[29][30]Nevertheless, maintaining normal testosterone levels in elderly men has been shown to improve many parameters that are thought to reduce cardiovascular disease risk, such as increased lean body mass, decreased visceral fat mass, decreased total cholesterol, and glycemic control.[31]

High androgen levels are associated with menstrual cycle irregularities in both clinical populations and healthy women.[32]

Sexual arousalEdit

When testosterone and endorphins in ejaculated semen meet the cervical wall after sexual intercourse, females receive a spike in testosterone, endorphin, and oxytocin levels, and males after orgasm during copulation experience an increase in endorphins and a marked increase in oxytocin levels. This adds to the hospitable physiological environment in the female internal reproductive tract for conceiving, and later for nurturing the conceptus in the pre-embryonic stages, and stimulates feelings of love, desire, and paternal care in the male (this is the only time male oxytocin levels rival a female’s).[citation needed]

Testosterone levels follow a nyctohemeral rhythm that peaks early each day, regardless of sexual activity.[33]

There are positive correlations between positive orgasm experience in women and testosterone levels where relaxation was a key perception of the experience. There is no correlation between testosterone and men’s perceptions of their orgasm experience, and also no correlation between higher testosterone levels and greater sexual assertiveness in either sex.[34]

Sexual arousal and masturbation in women produce small increases in testosterone concentrations.[35] The plasma levels of various steroids significantly increase after masturbation in men and the testosterone levels correlate to those levels.[36]

Mammalian studies

Studies conducted in rats have indicated that their degree of sexual arousal is sensitive to reductions in testosterone. When testosterone-deprived rats were given medium levels of testosterone, their sexual behaviors (copulation, partner preference, etc.) resumed, but not when given low amounts of the same hormone. Therefore, these mammals may provide a model for studying clinical populations among humans suffering from sexual arousal deficits such as hypoactive sexual desire disorder.[37]

In every mammalian species examined demonstrated a marked increase in a male’s testosterone level upon encountering a novelfemale. The reflexive testosterone increases in male mice is related to the male’s initial level of sexual arousal.[38]

In non-human primates, it may be that testosterone in puberty stimulates sexual arousal, which allows the primate to increasingly seek out sexual experiences with females and thus creates a sexual preference for females.[39] Some research has also indicated that if testosterone is eliminated in an adult male human or other adult male primate’s system, its sexual motivation decreases, but there is no corresponding decrease in ability to engage in sexual activity (mounting, ejaculating, etc.).[39]

In accordance with sperm competition theory, testosterone levels are shown to increase as a response to previously neutral stimuli when conditioned to become sexual in male rats.[40]This reaction engages penile reflexes (such as erection and ejaculation) that aid in sperm competition when more than one male is present in mating encounters, allowing for more production of successful sperm and a higher chance of reproduction.

Males

In men, higher levels of testosterone are associated with periods of sexual activity.[41]Testosterone also increased in heterosexual men after having had a brief conversation with a woman. The increase in testosterone levels was associated with the degree that the women thought the men were trying to impress them.[42]

Men who watch a sexually explicit movie have an average increase of 35% in testosterone, peaking at 60–90 minutes after the end of the film, but no increase is seen in men who watch sexually neutral films.[43] Men who watch sexually explicit films also report increased motivation, competitiveness, and decreased exhaustion.[44] A link has also been found between relaxation following sexual arousal and testosterone levels.[45]

Men’s levels of testosterone, a hormone known to affect men’s mating behaviour, changes depending on whether they are exposed to an ovulating or nonovulating woman’s body odour. Men who are exposed to scents of ovulating women maintained a stable testosterone level that was higher than the testosterone level of men exposed to nonovulation cues. Testosterone levels and sexual arousal in men are heavily aware of hormone cycles in females.[46] This may be linked to the ovulatory shift hypothesis,[47]where males are adapted to respond to the ovulation cycles of females by sensing when they are most fertile and whereby females look for preferred male mates when they are the most fertile; both actions may be driven by hormones.

Females

Androgens may modulate the physiology of vaginal tissue and contribute to female genital sexual arousal.[48] Women’s level of testosterone is higher when measured pre-intercourse vs pre-cuddling, as well as post-intercourse vs post-cuddling.[49] There is a time lag effect when testosterone is administered, on genital arousal in women. In addition, a continuous increase in vaginal sexual arousal may result in higher genital sensations and sexual appetitive behaviors.[50]

When females have a higher baseline level of testosterone, they have higher increases in sexual arousal levels but smaller increases in testosterone, indicating a ceiling effect on testosterone levels in females. Sexual thoughts also change the level of testosterone but not level of cortisol in the female body, and hormonal contraceptives may affect the variation in testosterone response to sexual thoughts.[51]

Testosterone may prove to be an effective treatment in female sexual arousal disorders,[52] and is available as a dermal patch. There is no FDA approved androgen preparation for the treatment of androgen insufficiency; however, it has been used off-label to treat low libido and sexual dysfunction in older women. Testosterone may be a treatment for postmenopausal women as long as they are effectively estrogenized.[52]

Romantic relationships

Falling in love decreases men’s testosterone levels while increasing women’s testosterone levels. There has been speculation that these changes in testosterone result in the temporary reduction of differences in behavior between the sexes.[53] However, it is suggested that after the „honeymoon phase“ ends—about four years into a relationship—this change in testosterone levels is no longer apparent.[53] Men who produce less testosterone are more likely to be in a relationship[54] or married,[55] and men who produce more testosterone are more likely to divorce;[55] however, causality cannot be determined in this correlation. Marriage or commitment could cause a decrease in testosterone levels.[56] Single men who have not had relationship experience have lower testosterone levels than single men with experience. It is suggested that these single men with prior experience are in a more competitive state than their non-experienced counterparts.[57] Married men who engage in bond-maintenance activities such as spending the day with their spouse/and or child have no different testosterone levels compared to times when they do not engage in such activities. Collectively, these results suggest that the presence of competitive activities rather than bond-maintenance activities are more relevant to changes in testosterone levels.[58]

Men who produce more testosterone are more likely to engage in extramarital sex.[55]Testosterone levels do not rely on physical presence of a partner; testosterone levels of men engaging in same-city and long-distance relationships are similar.[54] Physical presence may be required for women who are in relationships for the testosterone–partner interaction, where same-city partnered women have lower testosterone levels than long-distance partnered women.[59]

Fatherhood

Fatherhood also decreases testosterone levels in men, suggesting that the resulting emotional and behavioral changes promote paternal care.[60] The way testosterone levels change when a child is in distress is indicative of fathering styles. If the levels reduce, then there is more empathy by the father than in fathers whose levels go up.[61]

Motivation

Testosterone levels play a major role in risk-taking during financial decisions.[62][63]

Aggression and criminality

Most studies support a link between adult criminality and testosterone, although the relationship is modest if examined separately for each sex. Nearly all studies of juvenile delinquency and testosterone are not significant. Most studies have also found testosterone to be associated with behaviors or personality traits linked with criminality such as antisocial behavior and alcoholism. Many studies have also been done on the relationship between more general aggressive behavior/feelings and testosterone. About half the studies have found a relationship and about half no relationship.[64]

Testosterone is only one of many factors that influence aggression and the effects of previous experience and environmental stimuli have been found to correlate more strongly. A few studies indicate that the testosterone derivative estradiol (one form of estrogen) might play an important role in male aggression.[64][65][66][67] Studies have also found that testosterone facilitates aggression by modulating vasopressin receptors in the hypothalamus.[68]

The sexual hormone can encourage fair behavior. For the study subjects took part in a behavioral experiment where the distribution of a real amount of money was decided. The rules allowed both fair and unfair offers. The negotiating partner could subsequently accept or decline the offer. The fairer the offer, the less probable a refusal by the negotiating partner. If no agreement was reached, neither party earned anything. Test subjects with an artificially enhanced testosterone level generally made better, fairer offers than those who received placebos, thus reducing the risk of a rejection of their offer to a minimum. Two later studies have empirically confirmed these results.[69][70][71]However men with high testosterone were significantly 27% less generous in an ultimatum game.[72] The Annual NY Academy of Sciences has also found anabolic steroid use which increase testosterone to be higher in teenagers, and this was associated with increased violence.[73] Studies have also found administered testosterone to increase verbal aggression and anger in some participants.[74]

Testosterone is significantly correlated with aggression and competitive behaviour and is directly facilitated by the latter. There are two theories on the role of testosterone in aggression and competition.[75] The first one is the challenge hypothesis which states that testosterone would increase during puberty thus facilitating reproductive and competitive behaviour which would include aggression.[75]Thus it is the challenge of competition among males of the species that facilitates aggression and violence.[75] Studies conducted have found direct correlation between testosterone and dominance especially among the most violent criminals in prison who had the highest testosterone levels.[75] The same research also found fathers (those outside competitive environments) had the lowest testosterone levels compared to other males.[75]

The second theory is similar and is known as „evolutionary neuroandrogenic (ENA) theory of male aggression“.[76][77] Testosterone and other androgens have evolved to masculinize a brain in order to be competitive even to the point of risking harm to the person and others. By doing so, individuals with masculinized brains as a result of pre-natal and adult life testosterone and androgens enhance their resource acquiring abilities in order to survive, attract and copulate with mates as much as possible.[76] The masculinization of the brain is not just mediated by testosterone levels at the adult stage, but also testosterone exposure in the womb as a fetus. Higher pre-natal testosterone indicated by a low digit ratio as well as adult testosterone levels increased risk of fouls or aggression among male players in a soccer game.[78] Studies have also found higher pre-natal testosterone or lower digit ratio to be correlated with higher aggression in males.[79][80][81][82][83]

The rise in testosterone levels during competition predicted aggression in males but not in females.[84] Subjects who interacted with hand guns and an experimental game showed rise in testosterone and aggression.[85] Natural selection might have evolved males to be more sensitive to competitive and status challenge situations and that the interacting roles of testosterone are the essential ingredient for aggressive behaviour in these situations.[86] Testosterone produces aggression by activating subcortical areas in the brain, which may also be inhibited or suppressed by social norms or familial situations while still manifesting in diverse intensities and ways through thoughts, anger, verbal aggression, competition, dominance and physical violence.[87] Testosterone mediates attraction to cruel and violent cues in men by promoting extended viewing of violent stimuli.[88] Testosterone specific structural brain characteristic can predict aggressive behaviour in individuals.[89]

Estradiol is known to correlate with aggression in male mice.[90] Moreover, the conversion of testosterone to estradiol regulates male aggression in sparrows during breeding season.[91] Rats who were given anabolic steroids that increase testosterone were also more physically aggressive to provocation as a result of „threat sensitivity“.[92]

Brain

The brain is also affected by this sexual differentiation;[13] the enzyme aromataseconverts testosterone into estradiol that is responsible for masculinization of the brain in male mice. In humans, masculinization of the fetal brain appears, by observation of gender preference in patients with congenital diseases of androgen formation or androgen receptor function, to be associated with functional androgen receptors.[93]

There are some differences between a male and female brain (possibly the result of different testosterone levels), one of them being size: the male human brain is, on average, larger.[94] Men were found to have a total myelinated fiber length of 176,000 km at the age of 20, whereas in women the total length was 149,000 km (approx. 15% less).[95]

No immediate short term effects on mood or behavior were found from the administration of supraphysiologic doses of testosterone for 10 weeks on 43 healthy men.[96] A correlation between testosterone and risk tolerance in career choice exists among women.[62][97]

Attention, memory, and spatial ability are key cognitive functions affected by testosterone in humans. Preliminary evidence suggests that low testosterone levels may be a risk factor for cognitive decline and possibly for dementia of the Alzheimer’s type,[98][99][100][101] a key argument in life extension medicine for the use of testosterone in anti-aging therapies. Much of the literature, however, suggests a curvilinear or even quadratic relationship between spatial performance and circulating testosterone,[102]where both hypo- and hypersecretion (deficient- and excessive-secretion) of circulating androgens have negative effects on cognition.

 

Testosteron, Libido und der „Male Gaze“

 Ich hatte hier schon einmal einmal aus der Aussage des Transsexuellen Griffin Hansburry zitiert, der sich über die Wirkung von Testosteron, gerade auf seinen Sexualtrieb äußerte, zitiert nach einem Buch.

Jetzt habe ich durch Zufall die etwas längere Stelle gefunden, in der er noch einiges mehr anführt:

Alex Blumberg
What were some of the changes that you didn’t expect?

Griffin Hansbury
The most overwhelming feeling is the incredible increase in libido and change in the way that I perceived women and the way I thought about sex.

Before testosterone, I would be riding the subway, which is the traditional hotbed of lust in the city. And I would see a woman on the subway and I would think, she’s attractive. I’d like to meet her. What’s that book she’s reading? I could talk to her. This is what I would say. There would be a narrative. There would be this stream of language. It would be very verbal.

After testosterone, there was no narrative. There was no language whatsoever. It was just, I would see a woman who was attractive– or not attractive. She might have an attractive quality– nice ankles or something– and the rest of her would be fairly unappealing to me.

But that was enough to basically just flood my mind with aggressive pornographic images, just one after another. It was like being in a pornographic movie house in my mind. And I couldn’t turn it off. I could not turn it off. Everything I looked at, everything I touched turned to sex.

I was an editorial assistant. And I would be standing at the Xerox machine, and this big, shuddering, warm, inanimate object would just drive me crazy. It was very erotic to me.

Alex Blumberg
The Xerox machine.

Griffin Hansbury
The Xerox machine. Or a car. I remember walking up Fifth Avenue one day, and this red convertible went by. It was a Mustang. And I remember just getting this jolt in my pants, this very physical, visceral, sexual reaction to seeing a red convertible.

Alex Blumberg
What did you do with that? I mean, what did you think?

Griffin Hansbury
Well, I felt like a monster a lot of the time. And it made me understand men. It made me understand adolescent boys a lot. Suddenly, hair is sprouting and I’m turning into this beast. And I would really berate myself for it.

I remember walking up Fifth Avenue, and there was a woman walking in front of me. And she was wearing this little skirt and this little top. And I was looking at her ass. And I kept saying to myself, don’t look at it. Don’t look at it. And I kept looking at it.

And I walked past her. And this voice in my head kept saying, turn around to look at her breasts. Turn around. Turn around. Turn around. And my feminist, female background kept saying, don’t you dare, you pig. Don’t turn around. And I fought myself for a whole block, and then I turned around and checked her out.

And before, it was cool. When I would do a poetry reading, I would get up and I would read these poems about women on the street. And I was a butch dyke, and that was very cutting edge. And that was very sexy and raw. And now I’m just a jerk.

[LAUGHTER]

So I do feel like I’ve lost this edge, this nice, avant garde kind of–

And I’ve gotten into a lot of arguments with women friends, coworkers who did not know about my past as a female. I call myself a post-feminist. And I had a woman say, you’re not a post-feminist. You’re a misogynist. And I said, that’s impossible. I can’t be a misogynist. I couldn’t explain to her how I had come to this point in my life. And to her, I was just a misogynist. And that’s unfortunate because it’s a lot more complicated than that.

Alex Blumberg
[LAUGHTER] I’ll say. Wow. Testosterone didn’t just turn you into a man. It turned you into Rush Limbaugh.

Griffin Hansbury
I know. That I was not expecting. That I was not expecting.

Ich finde die Wirkung von Testosteron, gerade auch bei Transsexuellen, aber auch bei sonstiger Einnahme, macht deutlich, wie die Biologie in unsere Denkweise eingreift. Ich verweise insoweit auch auf die anderen Artikel dazu in diesem Blog:

Es spricht dagegen, dass diese Verhaltensweisen durch eine patriarchale Gesellschaft erlernt sind, allenfalls ist das Unterdrücken dieser erlernt, eben weil es als höflich gilt, nicht zu schauen.

Testosteron führt insofern vielleicht zu einer höheren Anfälligkeit für sexuelle Signale, wahrscheinlich gerade optische Signale. Vielleicht ist es auch schlicht eine Folge der höheren „Geilheit“, dass diese mit einer höheren Priorität wahrgenommen werden.

Die Biologie übt hier nicht im engeren Sinne eine Kontrolle über unser Handeln aus, wir haben nach wie vor einen freien Willen und können uns entscheiden eine Frau nicht „anzustarren“.  Aber sie verändert unsere Motivation zu einem bestimmten Verhalten und dies kann so stark sein, dass wir das Gefühl haben, dass wir die bestimmte Handlung einfach durchführen müssen. Dazu noch einmal seine genaue Schilderung

And I walked past her. And this voice in my head kept saying, turn around to look at her breasts. Turn around. Turn around. Turn around. And my feminist, female background kept saying, don’t you dare, you pig. Don’t turn around. And I fought myself for a whole block, and then I turned around and checked her out.

„ich kämpfte gegen mich selbst für einen ganzen Block und drehte mich dann um, um sie mir anzuschauen“ gibt gut wieder wie die Biologie in dieser Hinsicht arbeitet.

Das Gefühl an sich, nämlich „ich drehe mich erst etwas später um, damit es nicht so auffällt“ dürften auch die meisten Männer kennen. Auch die Selbstüberredung und Rechtfertigung, die mit biologischen Motivationen zusammenhängt werden die meisten kennen „Ich schau nur ganz kurz, ich bin weit genug weg, sie wird es gar nicht auf sich beziehen“ oder „ich habe heute eh kaum was gegessen, der Tag war so anstrengend, ich habe mich die Schokolade wirklich verdient, ich hole die Kalorien morgen wieder rein“.

Das ihm selbst sein Verhalten so ungewöhnlich erscheint macht auch den Unterschied zwischen Männern und Frauen deutlich.

Werte von Testosteron bei Mann und Frau über verschiedene Lebensphasen

Das Testosteron in biologischen Theorien zu Geschlecht und Geschlechterunterschieden eine wichtige Rolle spielt sollte den meisten Lesern dieses Blogs inzwischen deutlich geworden sein. Es lohnt sich daher einmal die unterschiedlichen Testosteronstände – pränatal und postnatal – näher zu betrachten. Hier also eine Grafik dazu:

 

Testosteron Maenner Frauen
Testosteron Maenner Frauen

Hier sieht man gut, wie unterschiedlich die Werte für Männer und Frauen sind und das bereits vor der Geburt und mit einiger Bewegung. Auch kurz nach der Geburt steigt der Testosteronspiegel bei männlichen Babies noch einmal deutlich an.  Das passt natürlich gut zu den Theorien, wie Geschlechterunterschiede durch pränatales Testosteron entstehen. Gut zu erklären wäre damit auch, wie in der Pubertät mit dem ansteigenden Testosteronspiegel das Interesse an Sex entsteht.

Zudem hatte Roslin auch noch einmal auf Zahlen hingewiesen:

Childhood

Testosterone levels are relatively low during infancy, averaging less than 30 nanograms/deciliter, or ng/dL, in male babies and below 10 ng/dL in female infants, according to the University of Michigan Health System. By 10 to 13 years of age, boys should have between 1 and 619 ng/dL of testosterone in their blood, while girls will run somewhere between 2 and 33 ng/dL.

Adolescence

Testosterone is a major trigger for puberty in boys, and normal blood levels in adolescent males surge as high as 970 ng/dL by the age of 17. A 17-year-old female, on the other hand, usually has only 8 to 53 ng/dL in her blood.

Adulthood

According to MayoClinic.com, testosterone levels in men peak during the teen and early adult years, then decrease about 1 percent a year after age 30. Men in their 20s or 30s generally score testosterone levels of 270 to 1,080 ng/dL, but women in that age bracket run between 10 and 70 ng/dL.

Senior Years

Testosterone drops down to 350 to 890 ng/dL in men between the ages of 40 to 59 years, and then stays between 350 and 720 ng/dL after the age of 60. Adult women run between 10 and 70 ng/dL before menopause, but see a big drop to 7 to 40 ng/dL with the onset of menopause.

Man sieht also auch noch mal in den Zahlen und üblichen Schwankungen, dass der Testosteronspiegel von Männern und Frauen sehr unterschiedlich sind.

Zu den Auswirkungen:

Testosteron, Lügen und prosoziales Verhalten

Eine Studie hat untersucht, wie sich Testosteron auf die Bereitschaft zu Lügen auswirkt:

Lying is a pervasive phenomenon with important social and economic implications. However, despite substantial interest in the prevalence and determinants of lying, little is known about its biological foundations. Here we study a potential hormonal influence, focusing on the steroid hormone testosterone, which has been shown to play an important role in social behavior. In a double-blind placebo-controlled study, 91 healthy men (24.32±2.73 years) received a transdermal administration of 50 mg of testosterone (n = 46) or a placebo (n = 45). Subsequently, subjects participated in a simple task, in which their payoff depended on the self-reported outcome of a die-roll. Subjects could increase their payoff by lying without fear of being caught. Our results show that testosterone administration substantially decreases lying in men. Self-serving lying occurred in both groups, however, reported payoffs were significantly lower in the testosterone group (p<0.01). Our results contribute to the recent debate on the effect of testosterone on prosocial behavior and its underlying channels.

Quelle: Testosterone Administration Reduces Lying in Men

In der Studie werden dann auch weitere Studien zur Wirkung von Testosteron behandelt:

Our findings contribute to the recent debate on a potential effect of testosterone on prosocial behavior [6], [9], [22]. So far, two studies suggest an effect of testosterone administration on prosocial behavior [6], [9]. However, these data are open to several interpretations regarding the underlying channel. Three hypotheses emerge from the debate [22]: 1) Testosterone has a direct influence on prosocial preferences, i.e., testosterone administration makes people more prosocial. 2) Testosterone increases concerns for social status, which may then lead to more prosocial behavior. 3) Testosterone affects beliefs about the behavior or beliefs of other players. One study [6] finds that single-dose administration of testosterone increases proposer offers in the ultimatum game in a sample of 60 women (but see [19], [23]). The authors interpret higher offers as an expression of testosterone enhanced status concerns, i.e., proposers want to avoid status threatening rejections and therefore behave more prosocially. However, high offers cannot be interpreted as prosocial behavior per se, but may be strategically motivated. Offers in the ultimatum game depend on beliefs about the rejection behavior of the other player. Recent research suggests that testosterone could render an individual’s belief about other people more pessimistic. For example, testosterone administration reduces trustworthiness judgments of unfamiliar faces [10] and testosterone is positively related to vigilant responses to angry faces [24]. In fact, testosterone could therefore lead proposers to expect a higher rejection threshold, which would also explain higher offers in the ultimatum game. The second study opts for a different behavioral paradigm to investigate the relation between testosterone and prosocial behavior [6]. This study finds that testosterone administration increases contributions in a public good game for high 2D:4D ratio individuals in a sample of 24 women. It is possible that testosterone administration rendered subjects more prosocial. However, as in [6] it cannot be ruled out that an effect of testosterone on beliefs drives the results since the incentive structure of the public good game was such that even a perfectly selfish player with certain beliefs would contribute to the public good.

Ich hatte die Studie bezüglich des Testosterons und dem höheren Beitrag zum Gemeinwohl hier auch bereits besprochen. Es scheint als habe Testosteron eine durchaus soziale Ader. In dem oben verlinkten Beitrag habe ich spekuliert, dass dies besonders wichtig ist, weil Männer gerade auf die Bündnisse untereinander angewiesen sind, sei es im Bezug auf Jagd oder auch Kampf. Eine andere Studie zu höheren Investitionen in die Gruppe hatte ich hier besprochen.

Aus der weiteren Besprechung in der Studie:

potential interpretation for our findings is that testosterone administration affects a concern for self-image [25], or pride [16], i.e., enhances behavior which will make a subject feel proud and leads to the avoidance of behavior considered “cheap” or dishonorable. Subjects in our testosterone group may therefore lie less. This is intriguing because pride could be an affective mechanism underlying a link between testosterone and dominance behavior. An interpretation of our findings in terms of pride is in line with anecdotal and correlational evidence indicating that testosterone plays a positive part in heroic altruism [17]. It is also in line with reports that high testosterone individuals display more disobedient behavior in prison environments where proud individuals may be less willing to follow the strict rules and comply with orders [26], [27]. Finally, a relation between pride, testosterone, and the willingness to engage in “cheap” behavior also fits the observation that the five inmates with the lowest testosterone levels in a sample of 87 female prison inmates were characterized as “sneaky” and “treacherous” by prison staff members [27]. Further experiments manipulating whether lying is an honorable action (e.g., lying for charity) or not (lying for self) are needed to clarify the role of pride in the effect of testosterone on human social behavior. An alternative interpretation of our results, which we cannot rule out, is that testosterone has a direct effect on prosocial behavior, making people more honest per se.

Das Fett markierte finde ich eine interessante Möglichkeit: Wenn Testosteron den Stolz beziehungsweise das allgemeine Statusdenken und Dominanzdenken betrifft, dann würde das meiner Meinung nach viele andere Punkte auch erklären. Es würde dann insbesondere von den kulturellen und sozialen Einstellungen abhängen, wie jemand diesen Konflikt umsetzt. Das mag in einem Experiment wie dem oben genannten dazu führen, dass man zu stolz ist, um zu betrügen, einen anderen Mann mag es verleiten, nicht vor einem körperlichen Konflikt zurückzuschrecken und diesen durch Gewalt zu entscheiden. Es würde auch gut in ein System der intrasexuellen Konkurrenz einzupassen sein, bei der Stress und niedrige Hierarchiestufen den Testoteronspiegel senken und somit vielleicht Tricks und Betrügereien lohnender machen, während bei einem hohen Testosteronspiegel die Wahrheit als Costly Signal in Kauf genommen werden kann.

Tiefe Stimmen und Politik

Tiefe Stimmen scheinen in der Politik eine gewisse Rolle zu spielen:

Dass die Höhe respektive Tiefe der Stimme die Attraktivität beeinflusst, ist in der Anthropologie an sich nichts Neues. Männer mit tieferen Stimmen werden laut Studien als anziehend, physisch stark und sozial dominant wahrgenommen. Bei Frauen ist die Sachlage etwas komplizierter: Hohe Stimmen gelten einerseits als attraktiv, andererseits scheinen sie der sozialen Dominanz abträglich zu sein.

Anderson hat nun mit der Biologin Susan Peters und dem Politikwissenschaftler Casey Klofstad die Stimme als Faktor politischer Wahlen untersucht. Die drei Forscher baten Frauen und Männer ins Labor, um folgenden Satz ins Mikrofon zu sprechen: „I urge you to vote for me this November“ – „Ich bitte Sie mich im November zu wählen“.

Daraus stellten die drei Forscher Varianten in höherer und tieferer Stimmlage her, die sie wiederum mehr als 150 Probanden vorspielten. Das Urteil war einhellig. Sowohl Frauen als auch Männer entschieden sich für die Kandidaten mit der tieferen Stimme. Eine zweite Testrunde legte Differenzen offen: Kandidatinnen mit sonorem Organ wurden sowohl von Frauen als auch von Männern als kompetenter, stärker und vertrauenswürdiger eingestuft.

Oder wie es die Forscher selbst fassen:

It is well known that non-human animals respond to information encoded in vocal signals, and the same can be said of humans. Specifically, human voice pitch affects how speakers are perceived. As such, does voice pitch affect how we perceive and select our leaders? To answer this question, we recorded men and women saying ‘I urge you to vote for me this November’. Each recording was manipulated digitally to yield a higher- and lower-pitched version of the original. We then asked men and women to vote for either the lower- or higher-pitched version of each voice. Our results show that both men and women select male and female leaders with lower voices. These findings suggest that men and women with lower-pitched voices may be more successful in obtaining positions of leadership. This might also suggest that because women, on average, have higher-pitched voices than men, voice pitch could be a factor that contributes to fewer women holding leadership roles than men. Additionally, while people are free to choose their leaders, these results clearly demonstrate that these choices cannot be understood in isolation from biological influences.

Quelle: Sounds like a winner: voice pitch influences perception of leadership capacity in both men and women

Aus Sicht der Evolution recht einfach zu erklären. Bei Männern lassen tiefe Stimmen auf viel Testosteron und große Brustkästen schließen. Also auf jemanden, der mit einer gewissen Wahrscheinlichkeit als Sieger aus einem intrasexuellen Konflikt hervorgeht. Es lohnt sich also ihn zu bevorzugen.

Bei Frauen wirken helle Stimmen attraktiver, weil sie auf Östrogene hindeuten. Tiefe Stimmen hingegen deuten eher auf Testosteron hin und damit in der Tat auf mehr Dominanz und Wettbewerbsfähigkeit. Auch das Auseinanderdriften ist damit verständlich.

Hinzu kommt, dass Frauen in einem Kampf um die Anführerrolle gegen stärkere Männer schlechte Karten haben, sofern sie nicht selbst andere Männer auf ihre Seite zogen. Auch nicht die beste Voraussetzung für den Kampf um die Führung, was vielleicht erklärt, warum wir Frauen in diesem Bereich weniger auf unserem Radar haben.

Ungerecht? Ja, natürlich. Aber die Natur ist eben nicht gerecht, moralisch oder gut.

Nachteilig für weibliche Kandidaten in der Politik, dem Betrieb oder andere Führungspositionen? Auch das. Aber es zeigt eben auch wieder, dass wir in solchen Bereichen immer noch von unserer Biologie beeinflusst werden, auch wenn wir das gar nicht in dem Maße merken. Die Leute werden ja nicht darauf abstellen, was eine tiefere Stimme bedeutet, sondern einfach ein bestimmtes Gefühl haben, dass der mit der tieferen Stimme irgendwie vertrauenserweckender, dominanter, anführerhafter klingt.

Ich zitiere noch mal aus der Studie:

Additionally, while people are free to choose their leaders, these results clearly demonstrate that these choices cannot be understood in isolation from biological influences

Wie so häufig.