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.

 

Räumliches Denken und mathematische Fähigkeiten

Eine interessante Studie behandelt die Frage, inwiefern räumliches Denken und mathematische Fähigkeiten in einem Zusammenhang stehen:

Despite considerable interest in the role of spatial intelligence in science, technology, engineering, and mathematics (STEM) achievement, little is known about the ontogenetic origins of individual differences in spatial aptitude or their relation to later accomplishments in STEM disciplines. The current study provides evidence that spatial processes present in infancy predict interindividual variation in both spatial and mathematical competence later in development. Using a longitudinal design, we found that children’s performance on a brief visuospatial change-detection task administered between 6 and 13 months of age was related to their spatial aptitude (i.e., mental-transformation skill) and mastery of symbolic-math concepts at 4 years of age, even when we controlled for general cognitive abilities and spatial memory. These results suggest that nascent spatial processes present in the first year of life not only act as precursors to later spatial intelligence but also predict math achievement during childhood.

Quelle: Spatial Processing in Infancy Predicts Both Spatial and Mathematical Aptitude in Childhood (Volltext)

Aus den Werten:

Räumliches Denken und Mathematik

Räumliches Denken und Mathematik

Also niedrige bis mittlere Werte.

Aus einer Besprechung der Studie:

Spatial reasoning measured in infancy predicts how children do at math at four years of age, finds a new study published in Psychological Science.

„We’ve provided the earliest documented evidence for a relationship between spatial reasoning and math ability,“ says Emory University psychologist Stella Lourenco, whose lab conducted the research. „We’ve shown that spatial reasoning beginning early in life, as young as six months of age, predicts both the continuity of this ability and mathematical development.“

Was dem Patriarchat wenig Zeit lässt für eine Unterdrückung, aber hoch effektiv wie es ist hat es das sicherlich dennoch geschafft.

Emory graduate student Jillian Lauer is co-author of the study.

The researchers controlled the longitudinal study for general cognitive abilities of the children, including measures such as vocabulary, working memory, short-term spatial memory and processing speed.

„Our results suggest that it’s not just a matter of smarter infants becoming smarter four-year-olds,“ Lourenco says. „Instead, we believe that we’ve honed in on something specific about early spatial reasoning and math ability.“

Gerade wenn es eine eigene „Fähigkeit“ auf dem Bereich gibt, dann kann es dort natürlich dann auch Unterschiede  und besondere Begabungen geben, die gerade diesen Bereich betreffen.

The findings may help explain why some people embrace math while others feel they are bad at it and avoid it. „We know that spatial reasoning is a malleable skill that can be improved with training,“ Lourenco says. „One possibility is that more focus should be put on spatial reasoning in early math education.“

Es dürfte auch erklären, warum einige dieses Training mehr Spass macht oder sie sogar von sich aus eher „Training“ in diesem Bereich betreiben, einfach in dem die Kinder zB lieber mit Spielzeug spielen, was diese Fähigkeiten fordert, während Kinder, die in dem Bereich nicht gut sind, keinen Spass an diesem Spielzeug haben.

Previous research has shown that superior spatial aptitude at 13 years of age predicts professional and creative accomplishments in the fields of science, technology, engineering and math more than 30 years later.

To explore whether individual differences in spatial aptitude are present earlier, Lourenco’s lab tested 63 infants, ages six months to 13 months, for a visual-spatial skill known as mental transformation, or the ability to transform and rotate objects in „mental space.“ Mental transformation is considered a hallmark of spatial intelligence.

The researchers showed the babies a series of paired video streams. Both streams presented a series of two matching shapes, similar to Tetris tile pieces, which changed orientation in each presentation. In one of the video streams, the two shapes in every third presentation rotated to become mirror images. In the other video stream, the shapes only appeared in non-mirror orientations. Eye tracking technology recorded which video stream the infants looked at, and for how long.

This type of experiment is called a change-detection paradigm. „Babies have been shown to prefer novelty,“ Lourenco explains. „If they can engage in mental transformation and detect that the pieces occasionally rotate into a mirror position, that’s interesting to them because of the novelty.“

Eye-tracking technology allowed the researchers to measure where the babies looked, and for how long. As a group, the infants looked significantly longer at the video stream with mirror images, but there were individual differences in the amount of time they looked at it.

Fifty-three of the children, or 84 percent of the original sample, returned at age four to complete the longitudinal study. The participants were again tested for mental transformation ability, along with mastery of simple symbolic math concepts. The results showed that the children who spent more time looking at the mirror stream of images as infants maintained these higher mental transformation abilities at age four, and also performed better on the math problems.

Langzeitstudien sind bei so etwas immer interessant. Und bereits sehr junge Kinder können die verschiedensten Nachrichten über geschlechtliche Fähigkeiten in dem Bereich auch noch nicht aufgenommen haben.

High-level symbolic math came relatively late in human evolution. Previous research has suggested that symbolic math may have co-opted circuits of the brain involved in spatial reasoning as a foundation to build on.

„Our work may contribute to our understanding of the nature of mathematics,“ Lourenco says. „By showing that spatial reasoning is related to individual differences in math ability, we’ve added to a growing literature suggesting a potential contribution for spatial reasoning in mathematics. We can now test the causal role that spatial reasoning may play early in life.“

In addition to helping improve regular early math education, the finding could help in the design of interventions for children with math disabilities. Dyscalculia, for example, is a developmental disorder that interferes with doing even simple arithmetic.

„Dyscalculia has an estimated prevalence of five to seven percent, which is roughly the same as dyslexia,“ Lourenco says. „Dyscalculia, however, has generally received less attention, despite math’s importance to our technological world.“

Ich finde die Studie auch gerade interessant, weil Geschlechterunterschiede im räumlichen Denken sehr gut belegt sind und auch viele Studien dazu existieren, die eine Abhängigkeit vom (pränatalen) Testosteronspiegel sehen:

Es passt insoweit, dass diese in jungen Jahren bereits erkennbar sind.

Dazu auch hier im Blog:

Das Gender Equality Paradox in den Naturwissenschaften, Technology und den Ingenieurwissenschaften sowie der Mathematik

Eine interessante Studie zum Gender Equality Paradox, von Gisbjert Stoet und David Geary:

The underrepresentation of girls and women in science, technology, engineering, and mathematics (STEM) fields is a continual concern for social scientists and policymakers. Using an international database on adolescent achievement in science, mathematics, and reading (N =472,242), we showed that girls performed similarly to or better than boys
in science in two of every three countries, and in nearly all countries, more girls appeared capable of college-level STEM study than had enrolled. Paradoxically, the sex differences in the magnitude of relative academic strengths and pursuit of STEM degrees rose with increases in national gender equality. The gap between boys’ science achievement and girls’ reading achievement relative to their mean academic performance was near universal. These sex differences in academic strengths and attitudes toward science correlated with the STEM graduation gap. A mediation analysis suggested that life-quality pressures in less gender-equal countries promote girls’ and women’s engagement with STEM subjects.

Quelle: The Gender-Equality Paradox in Science, Technology, Engineering, and Mathematics Education (Abstract/ Full (Scihub))

Für Leser dieses Blogs nichts neues: Insbesondere die Interessen der Frauen scheinen in eine andere Richtung zu gehen und sie von STEM-Fächern fern zu halten.

Die ersten Grafik zeigt Unterschiede zwischen Jungs und Mädchen in den Naturwissenschaften (Blau), in Mathematik (Grün) und im Lesen (Rot). Die Berechnung erfolgte, indem die Werte der Mädchen von den Werten der Jungs abgezogen wurden, waren die Mädchen also besser, dann schlägt es nach Links aus, waren die Jungs besser, dann nach Rechts.

Unterschiede wissenschaft Maenner Frauen

Unterschiede Wissenschaft Maenner Frauen

Wie man sieht, waren üblicherweise die Mädchen im Lesen besser, aber auch häufiger in Mathe oder Naturwissenschaften, wenn man PISA betrachtet.

Auf der rechten Seite findet sich dann eine Betrachtung, bei der es um die „persönliche Stärken“ ging:

Next, we calculated the percentage of boys and girls who had science, mathematics, or reading as their personal academic strength; this contrasts with the above analysis that focused on the overall magnitude of these strengths independently of whether they were the students’ personal strength. We found that on average (across nations), 24% of girls had science as their strength, 25% of girls had mathematics as their strength, and 51% had reading. The corresponding values for boys were 38% science, 42% mathematics, and 20% reading.

Thus, despite national averages that indicate that boys’ performance was consistently higher in science than that of girls relative to their personal mean across academic areas, there were substantial numbers of girls
within nations who performed relatively better in science than in other areas. Within Finland and Norway, two countries with large overall sex differences in the intraindividual science gap and very high GGGI scores, there were 24% and 18% of girls, respectively, who had science as their personal academic strength, relative to 37% and 46% of boys

Demnach waren Mädchen zwar in vielen Bereichen der Naturwissenschaften oder der Mathematik relativ stark, aber es war nicht ihre persönliche Stärke, vielleicht auch, weil sie eben im Lesen ganz besonders stark waren

Die nächste Grafik vergleicht die Unterschiede zwischen den Geschlechtern bei der Begeisterung für die Naturwissenschaften mit dem Global Gender Gap Index, der insbesondere angeben sollte, inwiefern Frauen in einem Land benachteiligt sind:

Unterschiede wissenschaft Maenner Frauen

Unterschiede wissenschaft Maenner Frauen

Dabei zeigt sich, dass gerade Länder mit sehr großen Unterschieden zwischen den Geschlechtern in dem Interesse für Naturwissenschaften einen hohen Wert bei dem Global Gender Pay Index haben. Ganz oben mit Dabei Länder wie Deutschland, Dänemark, Schweden und Island (das Land mit dem höchsten GGGI).

Die weitere Grafik zeigt in A) wie viele Frauen in der Schule die Befähigung hätten, ein STEM-Fach zu wählen, in B), wie viele die Fähigkeiten und die richtige Einstellung hätten um STEM zu wählen und in C) wie viele die Fähigkeiten und die Einstellung hätten und bei denen die Fähigkeiten auch gerade die persönliche Stärke wären. Und dies im Verhältnis dazu, wie viele Frauen dann tatsächlich in dem Bereich weiter machen.

Unterschiede wissenschaft Maenner Frauen

Unterschiede wissenschaft Maenner Frauen

Hier noch einmal der Erläuterungstext:

Fig. 5. Scatterplots showing the relation between the percentage of female students estimated to choose further science, technology, engineering, and math (STEM) study after secondary education and the estimated percentage of female STEM graduates in tertiary education. Red lines indicate the estimated (horizontal) and actual (vertical) average graduation percentage of women in STEM fields. For instance, in (c), we estimated that 34% of women would graduate college with a STEM degree (internationally), but only 28% did so. Identity lines (i.e., 45° lines) are colored blue; points above the identity lines indicate fewer women STEM graduates than expected. Panel (a) displays the percentage of female students estimated to choose STEM study on the basis of ability alone (see the text for criteria). Although there was considerable cross-cultural
variation, on average around 50% of students graduating in STEM fields could be women, which deviates considerably from the actual percentage of women among STEM graduates. The estimate of women STEM students shown in (b) was based on both ability, as in (a), and being above the international median score in science attitudes. The estimate shown in (c) is based on ability, attitudes, and having either mathematics or science as a personal strength

Wie man sieht sinkt der Anteil immer mehr, wenn man mehr Variablen dazu nimmt.

Es wäre interessant, noch einmal die Zahlen für die Jungs daneben zu stellen.

Aus der Studie:

Thus far, we have shown that the sex differences in STEM graduation rates and in science literacy as an academic strength become larger with gains in gender equality and that schools prepare more girls for further STEM study than actually obtain a STEM college degree. We will now consider one of the factors that might explain why the graduation gap may be larger in the more gender-equal countries. Countries with the highest gender equality tend to be welfare states (to varying degrees) with a high level of social security for all its citizens; in contrast, the less gender-equal countries have less secure and more difficult living conditions, likely leading to lower levels of life satisfaction (Pittau et al., 2010). This may in turn influence one’s utility beliefs about the value of science and pursuit of STEM occupations, given that these occupations are relatively high paying and thus provide the economic security that is less certain in countries that are low in gender equality. We used OLS as a measure of overall life circumstances; this is normally distributed and is a good proxy for economic opportunity and hardship and social and personal well-being (Pittau et al., 2010). In more equal countries, overall life satisfaction was higher (rs = .55, 95% CI = [.35, .70], p < .001, n = 62). Accordingly, we tested whether low prospects for a satisfied life may be an incentive for girls to focus more on science in school and, as adults, choose a career in a relatively higher paid STEM field. If our hypothesis is correct, then OLS should at least partially mediate the relation between gender equality and the sex differences in STEM graduation. A formal mediation analysis using a bootstrap method with 5,000 iterations confirmed the mediational model path of life satisfaction for STEM graduation (mean indirect effect = −0.19, SE = 0.08, Sobel’s z = −2.24, p < .025, 95% CI of bootstrapped samples = [−0.39, −0.04]). The effect of the direct path in the mediation model was statistically significant (mean direct effect = −0.34, SE = 0.135, 95% CI of bootstrapped samples = [−0.65, −0.02], p = .038), and the mediation was considered partial (proportion mediated = 0.35, 95% CI = [0.06, 0.95], p = .013; Table S3 in the Supplemental Material). A sensitivity analysis of this mediation (Imai, Keele, & Tingley, 2010; Tingley, Yamamoto, Hirose, Keele, & Imai, 2014) showed the point at which the average causal mediation effect (ACME) was approximately zero (ρ = −0.4, 95% CI = [−0.11, 0.15], R RM Y 2* 2* = 0.16, R R   M Y 2 2 = 0.07; Fig. S1 in the Supplemental Material). The latter finding suggests that an unknown third variable may have confounded the mediation model (see Discussion)

Das wäre also eine Erklärung darüber, dass in Ländern mit hohem GGGI üblicherweise auch ein gewisser Wohlstand und eine hohe Sicherheit geboten wird, so dass man eher meint seinen Neigungen nachgehen zu können, während in Ländern mit niedrigeren GGGI diese Sicherheit gerade in Berufen mit gutem Verdienst liegt.

Vielleicht auch nicht zu unterschätzen: Entsprechende Berufe erlauben auch eher das Verlassen des Landes in reichere, modernere Länder mit einem höheren Lebensstandard. Ich kenne einige Osteuropäer (m/w), die hier mit relativ technischen Berufen gute Stellen gefunden haben.

Using the most recent and largest international database on adolescent achievement, we confirmed that girls performed similarly or better than boys on generic science literacy tests in most nations. At the same time, women obtained fewer college degrees in STEM disciplines than men in all assessed nations, although the magnitude of this gap varied considerably. Further, our analysis suggests that the percentage of girls who would likely be successful and enjoy further STEM study was considerably higher than the percentage of women graduating in STEM fields, implying that there is a loss of female STEM capacity between secondary and tertiary education. One of the main findings of this study is that, paradoxically, countries with lower levels of gender equality had relatively more women among STEM graduates than did more gender-equal countries. This is a paradox, because gender-equal countries are those that give girls and women more educational and empowerment opportunities and that generally promote girls’ and women’s engagement in STEM fields (e.g., Williams & Ceci, 2015). In our explanation of this paradox, we focused on decisions that individual students may make and decisions and attitudes that are likely influenced by broader socioeconomic considerations. On the basis of expectancy-value theory (Eccles, 1983; Wang & Degol, 2013), we reasoned that students should at least, in part, base educational decisions on their academic strengths. Independently of absolute levels of performance, boys on average had personal academic strengths in science and mathematics, and girls had strengths in reading comprehension. Thus, even when girls’ absolute science scores were higher than those of boys, as in Finland, boys were often better in science relative to their overall academic average. Similarly, girls might have scored higher than boys in science, but they were often even better in reading. Critically, the magnitude of these sex differences in personal academic strengths and weaknesses was strongly related to national gender equality, with larger differences in more gender-equal nations. These intraindividual differences in turn may contribute, for instance, to parental beliefs that boys are better at science and mathematics than girls (Eccles & Jacobs, 1986; Gunderson, Ramirez, Levine, & Beilock, 2012). We also found that boys often expressed higher selfefficacy, more joy in science, and a broader interest in science than did girls. These differences were also larger in more gender-equal countries and were related to the students’ personal academic strength. We discuss some implications below (Interventions).

Dass Jungs die Naturwissenschaften mehr interessieren als die Mädchen und diese dafür andere Fächer eher interessieren, könnte auch daran liegen, dass es eben einen großen Dinge-Leute-Unterschied in den Interessen gibt.

Dazu noch einmal aus einer anderen Studie:

ocational interests predict educational and career choices, job performance, and career success (Rounds & Su, 2014). Although sex differences in vocational interests have long been observed (Thorndike, 1911), an appropriate overall measure has been lacking from the literature. Using a cross-sectional sample of United States residents aged 14 to 63 who completed the Strong Interest Inventory assessment between 2005 and 2014 (N 1,283,110), I examined sex, age, ethnicity, and year effects on work related interest levels using both multivariate and univariate effect size estimates of individual dimensions (Holland’s Realistic, Investigative, Artistic, Social, Enterprising, and Conventional). Men scored higher on Realistic (d 1.14), Investigative (d .32), Enterprising (d .22), and Conventional (d .23), while women scored higher on Artistic (d .19) and Social (d .38), mostly replicating previous univariate findings. Multivariate, overall sex differences were very large (disattenuated Mahalanobis’ D 1.61; 27% overlap). Interest levels were slightly lower and overall sex differences larger in younger samples. Overall sex differences have narrowed slightly for 18-22 year-olds in more recent samples. Generally very small ethnicity effects included relatively higher Investigative and Enterprising scores for Asians, Indians, and Middle Easterners, lower Realistic scores for Blacks and Native Americans, higher Realistic, Artistic, and Social scores for Pacific Islanders, and lower Conventional scores for Whites. Using Prediger’s (1982) model, women were more interested in people (d 1.01) and ideas (d .18), while men were more interested in things and data. These results, consistent with previous reviews showing large sex differences and small year effects, suggest that large sex differences in work related interests will continue to be observed for decades.

Dann aus der hier besprochenen Studie weiter:

Explanations

We propose that when boys are relatively better in science and mathematics while girls are relatively better at reading than other academic areas, there is the potential for substantive sex differences to emerge in STEM-related educational pathways. The differences are expected on the basis of expectancy-value theory and are consistent with prior research (Eccles, 1983; Wang & Degol, 2013). The differences emerge from a seemingly rational choice to pursue academic paths that are a personal strength, which also seems to be common academic advice given to students, at least in the United Kingdom (e.g., Gardner, 2016; Universities and Colleges Admissions Service, 2015). The greater realization of these potential sex differences in gender-equal nations is the opposite of what some scholars might expect intuitively, but it is consistent with findings for some other cognitive and social sex differences (e.g., Lippa, Collaer, & Peters, 2010; Pinker, 2008; Schmitt, 2015). One possibility is that the liberal mores in these cultures, combined with smaller financial costs of foregoing a STEM path (see below), amplify the influence of intraindividual academic strengths. The result would be the differentiation of the academic foci of girls and boys during secondary education and later in college, and across time, increasing sex differences in science as an academic strength and in graduation with STEM degrees. Whatever the processes that exaggerate these sex differences, they are abated or overridden in less genderequal countries. One potential reason is that a well-paying STEM career may appear to be an investment in a more secure future. In line with this, our mediation analysis suggests that OLS partially explains the relation between gender equality and the STEM graduation gap. Some caution when interpreting this result is needed, though. Mediation analysis depends on a number of assumptions, some of which can be tested using a sensitivity analysis, which we conducted (Imai, Keele, & Yamamoto, 2010). The sensitivity analysis gives an indication of the correlation between the statistical error component in the equations used for predicting the mediator (OLS) and the outcome (STEM graduation gap); this includes the effect of unobserved confounders. Given the range of ρ values in the sensitivity analysis (Fig. S1), it is possible that a third variable could be associated with OLS and the STEM graduation gap. A related limitation is that the sensitivity analysis does not explore confounders that may be related to the predictor variable (i.e., GGGI). Future research that includes more potential confounders is needed, but such data are currently unavailable for many of the countries included in our analysis. Relation to previous studies of gender equality and educational outcomes Our current findings agree with those of previous studies in that sex differences in mathematics and science performance vary strongly between countries, although we also believe that the link between measures of gender equality and these educational gaps (e.g., as demonstrated by Else-Quest, Hyde, & Linn, 2010; Guiso, Monte, Sapienza, & Zingales, 2008; Hyde & Mertz, 2009; Reilly, 2012) can be difficult to determine and is not always found (Ellison & Swanson, 2010; for an in-depth discussion, see Stoet & Geary, 2015). We believe that one factor contributing to these mixed results is the focus on sex differences in absolute performance, as contrasted with sex differences in academic strengths and associated attitudes. As we have shown, if absolute performance, interest, joy, and selfefficacy alone were the basis for choosing a STEM career, we would expect to see more women entering STEM career paths than do so (Fig. 5). It should be noted that there are careers that are not STEM by definition, although they often require STEM skills. For example, university programs related to health and health care (e.g., nursing and medicine) have a majority of women. This may partially explain why even fewer women than we estimated pursue a college degree in STEM fields despite obvious STEM ability and interest. Interventions Our results indicate that achieving the goal of parity in STEM fields will take more than improving girls’ science education and raising overall gender equality. The generally overlooked issue of intraindividual differences in academic competencies and the accompanying influence on one’s expectancies of the value of pursuing one type of career versus another need to be incorporated into approaches for encouraging more women to enter 12 Stoet, Geary the STEM pipeline. In particular, high-achieving girls whose personal academic strength is science or mathematics might be especially responsive to STEM-related interventions. In closing, we are not arguing that sex differences in academic strengths or wider economic and life-risk issues are the only factors that influence the sex difference in the STEM pipeline. We are confirming the importance of the former (Wang et al., 2013) and showing that the extent to which these sex differences manifest varies consistently with wider social factors, including gender equality and life satisfaction. In addition to placing the STEM-related sex differences in broader perspective, the results provide novel insights into how girls’ and women’s participation in STEM might be increased in gender-equal countries.

Der Rat „Wähle Fächer nach deinen Stärken“ ist ja in der Tat etwas, was man Leuten raten würde. Und da würden eben viele Mädchen in der Schule dann beispielsweise eher Sprachen als Leistungskurs wählen oder Deutsch oder andere Fächer, in denen sie solche Stärken besser ausspielen können. Wer aber einen Englisch und Geschichte als Leistungskurs hat, der wird dann üblicherweise nicht Physik studieren, selbst wenn derjenige auch in Physik keine schlechten Noten hatte.

Zudem gibt es eben auch Fächer, die weniger „theoretisch“ sind und in denen man mehr mit Leuten zu tun hat, in denen man ebenfalls bestimmte Fähigkeiten aus dem oben geprüften Bereichen braucht, etwa BWL oder medizinische Fächer.

Das alles mag dazu beitragen, dass Mädchen sich bereits früh für andere Bereiche entscheiden und dort ihre Stärken ausbauen, so dass sie dann später nicht mehr die STEM-Fächer studieren, für die sie sich zudem auch weniger interessieren.

Siehe auch:

 

Geschlechterunterschiede im Gehirn sind bereits im Alter von einem Monat vorhanden

Ein interessante Studie zu Geschlechterunterschieden im Gehirn bei Säuglingen:

The developing brain undergoes systematic changes that occur at successive stages of maturation. Deviations from the typical neurodevelopmental trajectory are hypothesized to underlie many early childhood disorders; thus, characterizing the earliest patterns of normative brain development is essential. Recent neuroimaging research provides insight into brain structure during late childhood and adolescence; however, few studies have examined the infant brain, particularly in infants under 3 months of age. Using high-resolution structural MRI, we measured subcortical gray and white matter brain volumes in a cohort (N = 143) of 1-month infants and examined characteristics of these volumetric measures throughout this early period of neurodevelopment. We show that brain volumes undergo age-related changes during the first month of life, with the corresponding patterns of regional asymmetry and sexual dimorphism. Specifically, males have larger total brain volume and volumes differ by sex in regionally specific brain regions, after correcting for total brain volume. Consistent with findings from studies of later childhood and adolescence, subcortical regions appear more rightward asymmetric. Neither sex differences nor regional asymmetries changed with gestation-corrected age. Our results complement a growing body of work investigating the earliest neurobiological changes associated with development and suggest that asymmetry and sexual dimorphism are present at birth.

Quelle: Investigation of brain structure in the 1-month infant (Scihub Volltext Link)

Aus der Studie:

Unterschiede Gehirn Mann Frau 1 Monat

Unterschiede Gehirn Mann Frau 1 Monat

Da geht es um die

  1. Größe des Gehirns von männlichen und weiblichen Babies nach Geburt.
  2. Das Volumen der weißen Substanz im Gehirn
  3. Das Volumen der grauen Substanz im Gehirn

Wie man sieht ist das Gehirn der männlichen Babies im Durchschnitt zB größer, und zwar über die hier erfassten Alter hinweg, auch wenn es einzelne männliche Babies mit relativ kleinen und einige Mädchen mit relativ großen Gehirnvolumen gibt. Der Trend ist aber recht deutlich.

Auch die Daten zu den verschiedenen Bereichen zeigen deutliche Unterschiede:

Unterschiede Gehirn Mann Frau 1 Monat

Unterschiede Gehirn Mann Frau 1 Monat

Es wird schwer das mit einer unterschiedlichen Sozialisiation zu erklären. Sie müsste dann wohl bereits im Mutterleib ansetzen. Was allerdings pränatale Hormone in der Tat machen, wie man beispielsweise an dem Testosteronspiegel sieht:

Testosteron Maenner Frauen

Testosteron Maenner Frauen

Aus einer Besprechung der Studie:

Dean’s team found that the boys’ brains were 8.3 per cent bigger, in line with the sex difference in brain volume found in adults and the few other available infant studies. Also as seen in adults, male brains had relatively more white matter (connecting tissue) and female brains more grey matter, relative to total brain size.

A number of specific neural areas were larger in males, such as parts of the limbic system involved in emotions, including the amygdala, insula, thalamus and putamen. The researchers also found evidence for relatively larger hippocampi, an area involved in memory, which has more commonly been found to be larger in females, although not universally so. Meanwhile female brains were relatively larger in other limbic areas such as parts of the cingulate gyrus, caudate and parahippocampal gyrus, and they had a few white-matter structures that were relatively larger.

These sex differences were smaller than has been observed in adults, which suggests that maturation continues this differentiation, likely through the high volume of sex steroid receptors in these brain areas. The alternative suggestion is that the subsequent differentiation is due to socialisation, but for the forces of socialisation to work along the same lines as pre-existing biological forces would suggest that socialisation is at most a feedback loop between biology and society.

There were a lot of brain areas that differed structurally between the sexes, but it would be irresponsible to draw any firm conclusions about what they might mean for function and behaviour. For instance,  what could differences in overall insula size possibly mean psychologically when the area is associated with “compassion and empathy, perception, motor control, self-awareness, cognitive functioning”, “interpersonal experience” and “psychopathology”?

Insofern liegt noch viel Arbeit vor den Forschern, bis sie die Unterschiede wirklich verstehen. Aber dennoch entzieht diese Studie vielen, die auf einen Blank Slate abstellen und annehmen, dass Geschlechterunterschiede nur auf Sozialisiation zurück gehen können einiges an Boden bzw. erfordert, dass diese ihre Thesen kritisch hinterfragen.

Vgl auch:

Homosexualität am Gesicht erkennen

Die Studie war bereits Thema in den Kommentaren:

We show that faces contain much more information about sexual orientation than can be perceived and interpreted by the human brain. We used deep neural networks to extract features from 35,326 facial images. These features were entered into a logistic regression aimed at classifying sexual orientation. Given a single facial image, a classifier could correctly distinguish between gay and heterosexual men in 81% of cases, and in 74% of cases for women. Human judges achieved much lower accuracy: 61% for men and 54% for women. The accuracy of the algorithm increased to 91% and 83%, respectively, given five facial images per person. Facial features employed by the classifier included both fixed (e.g., nose shape) and transient facial features (e.g., grooming style). Consistent with the prenatal hormone theory of sexual orientation, gay men and women tended to have gender-atypical facial morphology, expression, and grooming styles. Prediction models aimed at gender alone allowed for detecting gay males with 57% accuracy and gay females with 58% accuracy. Those findings advance our understanding of the origins of sexual orientation and the limits of human perception. Additionally, given that companies and governments are increasingly using computer vision algorithms to detect people’s intimate traits, our findings expose a threat to the privacy and safety of gay men and women.

Quote: Deep neural networks are more accurate than humans at detecting sexual orientation from facial images.

Aus dem Spiegelartikel dazu:

Sie zeigten, wie ein Computer mithilfe von Gesichterkennungssoftware die sexuelle Orientierung von Menschen erkennt.

Und das mit extrem hoher Trefferquote: Ausgehend von nur einem Foto erkannte das Programm 81 Prozent aller schwulen Männer und 74 Prozent aller homosexuellen Frauen. Menschliche Probanden, denen die gleichen Bilder vorgelegt wurden, kamen hier nur auf 61 und 54 Prozent Trefferquote. Noch gruseliger wurden die Ergebnisse, wenn man dem Rechner fünf Bilder einer Person vorlegte. Dann erkannte die Software 91 Prozent der homosexuellen Männer und 83 Prozent der Frauen.

Auch interessant: Das dort verlinkte Bild:

homosexuell Gesicht

homosexuell Gesicht

Das linke Gesicht wurde aus heterosexuellen Personen zusammengesetzt, das rechte aus homsoexuellen Personen.

Interessanterweise kommen mir in beiden Fällen die heterosexuellen Gesichter unattraktiver vor. Vielleicht auch nur, weil  sie jeweils dicker aussehen.

Aus meiner Sicht ein durchaus zu erwartendes Ergebnis:

Die vorherrschende Theorie führt an, dass Homosexualität in einer engen Verbindung mit insbesondere pränatalen Hormonen steht:

Und auch Gesichter sind männlicher oder weiblicher unter der Einwirkung der Hormone:

vgl zB diese Studie:

Prenatal testosterone may have a powerful masculinizing effect on postnatal physical characteristics. However, no study has directly tested this hypothesis. Here, we report a 20-year follow-up study that measured testosterone concentrations from the umbilical cord blood of 97 male and 86 female newborns, and procured three-dimensional facial images on these participants in adulthood (range: 21–24 years). Twenty-three Euclidean and geodesic distances were measured from the facial images and an algorithm identified a set of six distances that most effectively distinguished adult males from females. From these distances, a ‘gender score’ was calculated for each face, indicating the degree of masculinity or femininity. Higher cord testosterone levels were associated with masculinized facial features when males and females were analysed together (n = 183; r = −0.59), as well as when males (n = 86; r = −0.55) and females (n = 97; r = −0.48) were examined separately (p-values < 0.001). The relationships remained significant and substantial after adjusting for potentially confounding variables. Adult circulating testosterone concentrations were available for males but showed no statistically significant relationship with gendered facial morphology (n = 85, r = 0.01, p = 0.93). This study provides the first direct evidence of a link between prenatal testosterone exposure and human facial structure.

Ich hatte einmal zu den Gründen für Homosexualität ausgeführt:

1. Männliche Homosexualität:

  • Die Hoden des Fötus produzieren nicht genug Testosteron
  • Die Hoden des Fötus entwickeln sich zu spät und produzieren erst nach der entscheidenen Phase Testosteron
  • Das Testosteron wird mangels entsprechender Rezeptoren an der Blut-Hirn-Schranke/im ganzen Körper nicht erkannt.
  • Das Testosteron wird mangels entsprechender Rezeptoren an der Blut-Hirn-Schranke nur teilweise/abgeschächt erkannt
  • Das Östrogen wird im Gehirn mangels entsprechender Rezeptoren nicht erkannt.
  • Die Mutter stellt in der entscheidenden Phase nicht genug Testosteron bereit.
  • Der Schwellenwert ist überhoch eingestellt, so dass das weibliche Programm trotz ausreichend Testosteron nicht durchgeführt wird.
  • Antiandrogene blockieren die Rezeptoren in der entscheidenden Phase.
  • Medikamente/andere Stoffe senken den Testosteronspiegel in der entscheidenden Phase
  • Umweltbedingungen senken des Testosteronspiegel in der entscheidenden Phase
  • Ein Zusammenspiel dieser Faktoren

2. Weibliche Homosexualität:

  • Der Fötus hat einen erhöhten Testosteronspiegel (über eine Überproduktion der Nebennierenrinde und der Eierstöcke)
  • Die Mutter stellt ein Übermass an Testosteron bereit.
  • Der Schwellenwert für das 2.  Bauschema Mann ist in diesem Bereich extrem niedrig angesetzt.
  • Medikamente sorgen für eine Erhöhung des Testosteronspiegels in der empfindlichen Phase
  • überempfindliche Rezeptoren suggerieren einen erhöhten Testosteronspiegel.
  • Ein Zusammenspiel dieser Faktoren

Wie man sieht muss damit nicht zwangsläufig die Homosexualität sich auch im Gesicht zeigen. Etwa weil der „Schwellenwert“ niedrig angesetzt ist oder der Wert nur in einer bestimmten Phase sehr hoch ist. Gerade wenn der Hormonspiegel aber dauerhaft erhöht ist spricht vieles für eine Übereinstimmung.

Insofern aus meiner Sicht ein sehr nachvollziehbares Ergebnis

 

Spielverhalten in der Jugend und sexuelle Orientierung

Eine interessante Langzeitstudie beobachtete Spielverhalten und verglich sie dann später mit der sexuellen Orientierung als Erwachsener:

Abstract
Lesbian and gay individuals have been reported to show more interest in other-sex, and/or less interest in same-sex, toys, playmates, and activities in childhood than heterosexual counterparts.

Yet, most of the relevant evidence comes from retrospective studies or from prospective studies of clinically-referred, extremely gender nonconforming children. In addition, findings are mixed regarding the relationship between childhood gender-typed behavior and the later sexual orientation spectrum from exclusively heterosexual to exclusively lesbian/gay.

The current study drew a sample (2,428 girls and 2,169 boys) from a population-based longitudinal study, and found that the levels of gender-typed behavior at ages 3.50 and 4.75 years, although less so at age 2.50 years, significantly and consistently predicted adolescents’ sexual orientation at age 15 years, both when sexual orientation was conceptualized as two groups or as a spectrum. In addition, within-individual change in gender-typed behavior during the preschool years significantly related to adolescent sexual orientation, especially in boys. These results suggest that the factors contributing to the link between childhood gender-typed behavior and sexual orientation emerge during early development. Some of those factors are likely to be nonsocial, because nonheterosexual individuals appear to diverge from gender norms regardless of social encouragement to conform to gender roles.

Quelle: Childhood Gender-Typed Behavior and Adolescent Sexual Orientation: A Longitudinal Population-Based Study

Ein Junge, der eher mädchentypisches Spielzeug mag, ist also mit einer höheren Wahrscheinlichkeit schwul.

Die Frage ist nun, in welcher Richtung die Kausalität verläuft:

  • macht spielen mit Mädchenspielzeug schwul?
  • spielen Schwule eher mit Mädchenspielzeug, weil sie „weiblicher“ sind

Letzterer Theorie würde gut zu den „Hormontheorien“ passen. Danach entsteht Homosexualität, weil bestimmte Hormone nicht zur richtigen Zeit vor der Geburt, in der die für die sexuelle Orientierung zuständigen Gehirnbereiche angelegt werden, einen bestimmten Hormonstand haben. Die Hormone, insbesondere pränatales Testosteron, regelt, ob man Männer oder Frauen attraktiv findet: Ist zu dieser Zeit ein hinreichend hoher Stand an Testosteron vorhanden (und spielen andere, vielleicht epigenetische Faktoren mit), dann wird der Junge heterosexuell, wenn nicht, dann besteht eine Chance, dass er homosexuell wird. Die gleichen Hormone beinflussen auch die Vorliebe für bestimmte Spielzeuge. Dabei wird davon ausgegangen, dass Spielen eine Vorbereitung auf das Erwachsenenleben sind, so dass es auch sinnvoll ist, dass Personen, die ganz andere Aufgaben im Erwachsenenleben erfüllen werden, sich auch eher für andere Bereiche interessieren, mit denen sie dies spielerisch erlernen können.

Die erste Theorie hingegen würde wohl eher stark konservativen Kräften in die Hände spielen, würde aber immerhin zu einem Blank Slate und Rollentheorien passen: Weil er später lernt, dass es Frauenspielzeug ist, würde er sich eher als Frau verhalten und deswegen auch eher auf Männer stehen. Wäre für mich eher ein sehr gewagter Schluss, der auch nicht dazu passt, dass auch andere Kinder, bei denen man die Hormone gemessen hat, etwa CAH-Mädchen ein von der Geschlechterrolle abweichendes Verhalten zeigen und lieber mit dem anderen Geschlecht und dessen Spielzeug spielen.

Hier die Werte:

sexuelle Orientierung und Spielverhalten Mädchen

sexuelle Orientierung und Spielverhalten Mädchen

sexuelle Orientierung und Spielverhalten jungen

sexuelle Orientierung und Spielverhalten jungen

In Beiden sieht man, dass die Unterschiede immer größer werden. Mit etwas unter 5 Jahren erreichen die 100% heterosexuellen Mädchen einen Wert bei „männliches Spielverhalten“ von 34,79 und die 100% lesbischen Mädchen einen Wert von 53,97

Bei den Jungs ist es für „männlicheres Spielverhalten “ bei den älteren Kindern bei den Heteros 63,79 und bei den Homosexuellen 54,83.

Es ist auch interessant, dass sich die Unterschiede im Spielverhalten bei den Jungs durchgehend mit dem „Grad“ der späteren sexuellen Orientierung hin zum gleichen Geschlecht vergrößern.

Bei den Mädchen ist dies weniger eindeutig, der große Sprung kommt erst bei denen, die 100% lesbisch sind. Das übrige Feld liegt teilweise recht dicht beieinander.

Das könnte damit zusammenhängen, dass die notwendige „Schwelle“ in den Hormonen bei Frauen höher liegt.

Die Studie passt aus meiner Sicht sehr gut zu den biologischen Erklärungen und es scheint mir schwer zu sein, sie in ein soziales Modell zu bringen. Wer dazu eine Idee hat, der kann es gerne in den Kommentaren darstellen.

In der oben verlinkten Tabelle ist auch noch am Ende eine Auswertung der Daten zu einzelnen Aktivitäten vorhanden: Mit dem gleichen Geschlecht Händchen halten zeigt geringere Unterschiede im Spielverhalten als tatsächlicher Sex, gerade bei Männern.

Geschlechtertypisches Verhalten und sexuelle Orientierung

Eine interessante Studie hat geschlechtertypisches Verhalten und sexuelle Orientierung verglichen:

Abstract Lesbian and gay individuals have been reported to show more interest in other-sex, and/or less interest in same-sex, toys, playmates, and activities in childhood than heterosexual counterparts. Yet, most of the relevant evidence comes from retrospective studies or from prospective studies of clinically-referred, extremely gender nonconforming children. In addition, findings are mixed regarding the relationship between childhood gender-typed behavior and the later sexual orientation spectrum from exclusively heterosexual to exclusively lesbian/gay. The current study drew a sample (2,428 girls and 2,169 boys) from a population-based longitudinal study, and found that the levels of gender-typed behavior at ages 3.50 and 4.75 years, although less so at age 2.50 years, significantly and consistently predicted adolescents’ sexual orientation at age 15 years, both when sexual orientation was conceptualized as two groups or as a spectrum. In addition, within-individual change in gender-typed behavior during the preschool years significantly related to adolescent sexual orientation, especially in boys. These results suggest that the factors contributing to the link between childhood gender-typed behavior and sexual orientation emerge during early development. Some of those factors are likely to be nonsocial, because nonheterosexual individuals appear to diverge from gender norms regardless of social encouragement to conform to gender roles.

Quelle: Childhood Gender-Typed Behavior and Adolescent Sexual Orientation: A Longitudinal Population-Based Study

Ein Ergebnis, welches nach den biologischen Theorien, nach denen die sexuelle Orientierung und das geschlechtertypische Verhalten insbesondere durch pränatales Testosteron hervorgerufen werden und später unter der Wirkung der Sexualhormone, insbesondere auch Testosteron weiterentwickelt wird, gut zu erklären ist. Es ist allerdings aus meiner Sicht weit aus schwieriger mit sozialen Theorien zu erklären.

Yeyo dazu:

Wie er richtig anmerkt kann man auch überlegen, ob andere Kausalitäten vorliegen: Es könnte auch sein, dass tatsächliche geschlechteruntypisches Spielen schwul macht. Das wäre allerdings eine Interpretation, welche die meisten Genderfeministen wohl eher nicht vertreten werden wollen, da sie sehr konservativen Kreisen und ihren Ideen, dass man Kinder eben möglichst mit den für ihr Geschlecht typischen Spielzeug spielen lassen sollte, entspricht.

Es zeigt, folgt man der Theorie, dass beides – Geschlechteruntypisches Spielen und eine von der Norm abweichende Sexualität – auf einem gemeinsamen Grund beruht, nämlich den Hormonen, aber auch gut, wie dieser weit verbreitete Irrtum, dass das falsche Spielzeug die sexuelle Orientierung beeinflusst entstehen konnte. Es wäre dann eine schlichte Falschdeutung der Kausalitäten.