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:

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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.

 

 

 

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.

Studiensammlung 4: (Prenatale) Hormone und Geschlechterunterschiede im Gehirn und Verhalten

Und weil wir heute eh schon eine Studie hier zu Gehirnunterschieden haben hier ein paar weitere Studien:

1.

Fetal Testosterone Influences Sexually Dimorphic Gray Matter in the Human Brain

In nonhuman species, testosterone is known to have permanent organizing effects early in life that predict later expression of sex differences in brain and behavior. However, in humans, it is still unknown whether such mechanisms have organizing effects on neural sexual dimorphism. In human males, we show that variation in fetal testosterone (FT) predicts later local gray matter volume of specific brain regions in a direction that is congruent with sexual dimorphism observed in a large independent sample of age-matched males and females from the NIH Pediatric MRI Data Repository. Right temporoparietal junction/posterior superior temporal sulcus (RTPJ/pSTS), planum temporale/parietal operculum (PT/PO), and posterior lateral orbitofrontal cortex (plOFC) had local gray matter volume that was both sexually dimorphic and predicted in a congruent direction by FT. That is, gray matter volume in RTPJ/pSTS was greater for males compared to females and was positively predicted by FT. Conversely, gray matter volume in PT/PO and plOFC was greater in females compared to males and was negatively predicted by FT. Subregions of both amygdala and hypothalamus were also sexually dimorphic in the direction of Male > Female, but were not predicted by FT. However, FT positively predicted gray matter volume of a non-sexually dimorphic subregion of the amygdala. These results bridge a long-standing gap between human and nonhuman species by showing that FT acts as an organizing mechanism for the development of regional sexual dimorphism in the human brain.

Ergänzung:

(FT was measured from amniotic fluid samples collected between 13 and 20 weeks of gestation (mean FT, 0.79 nmol/L; SD, 0.34 nmol/L; range, 0.25–1.70 nmol/L).

2.

The Impact of Sex, Puberty, and Hormones on White Matter Microstructure in Adolescents

Background: During adolescence, numerous factors influence the organization of the brain. It is unclear what influence sex and puberty have on white matter microstructure, as well as the role that rapidly increasing sex steroids play. Methods: White matter microstructure was examined in 77 adolescents (ages 10–16) using diffusion tensor imaging. Multiple regression analyses were performed to examine the relationships between fractional anisotropy (FA) and mean diffusivity (MD) and sex, puberty, and their interaction, controlling for age. Follow-up analyses determined if sex steroids predicted microstructural characteristics in sexually dimorphic and pubertal-related white matter regions, as well as in whole brain. Results: Boys had higher FA in white matter carrying corticospinal, long-range association, and cortico-subcortical fibers, and lower MD in frontal and temporal white matter compared with girls. Pubertal development was related to higher FA in the insula, while a significant sex-by-puberty interaction was seen in superior frontal white matter. In boys, testosterone predicted white matter integrity in sexually dimorphic regions as well as whole brain FA, whereas estradiol showed a negative relationship with FA in girls. Conclusions: Sex differences and puberty uniquely relate to white matter microstructure in adolescents, which can partially be explained by sex steroids.

Ergänzung:

Hormonal Assessment
Four milliliters of blood was collected via venipuncture between the hours of 7:00 to 10:00 AM at the Oregon Clinical and Translational Research Institute in the same week as the imaging session.

3.

Regional sex differences in grey matter volume are associated with sex hormones in the young adult human brain

Previous studies suggest organizing effects of sex hormones on brain structure during early life and puberty, yet little is known about the adult period. The aim of the present study was to elucidate the role of 17β-estradiol, progesterone, and testosterone on cortical sex differences in grey matter volume (GM) of the adult human brain. To assess sexual dimorphism, voxel-based morphometry (VBM) was applied on structural magnetic resonance images of 34 healthy, young adult humans (17 women, 17 men, 26.6 ± 5 years) using analyses of covariance. Subsequently, circulating levels of sex hormones were associated with regional GM using linear regression analyses. After adjustment for sex and total GM, significant associations of regional GM and 17β-estradiol were observed in the left inferior frontal gyrus (β = 0.39, p = 0.02). Regional GM was inversely associated with testosterone in the left inferior frontal gyrus (β = −0.16, p = 0.04), and with progesterone in the right temporal pole (β = −0.39, p = 0.008). Our findings indicate that even in young adulthood, sex hormones exert organizing effects on regional GM. This might help to shed further light on the underlying mechanisms of both functional diversities and congruence between female and male brains.

4.

Pubertal hormones organize the adolescent brain and behavior

Maturation of the reproductive system during puberty results in elevated levels of gonadal steroid hormones. These hormones sculpt neural circuits during adolescence, a time of dramatic rewiring of the nervous system. Here, we review the evidence that steroid-dependent organization of the adolescent brain programs a variety of adult behaviors in animals and humans. Converging lines of evidence indicate that adolescence may be a sensitive period for steroid-dependent brain organization and that variation in the timing of interactions between the hormones of puberty and the adolescent brain leads to individual differences in adult behavior and risk of sex-biased psychopathologies.

5.

Prenatal hormones and childhood sex-segregation: Playmate and play style preferences in girls with congenital adrenal hyperplasia

We investigated playmate and play style preference in children with congenital adrenal hyperplasia (CAH) (26 females, 31 males) and their unaffected siblings (26 females, 17 males) using the Playmate and Play Style Preferences Structured Interview (PPPSI). Both unaffected boys and girls preferred same-sex playmates and sex-typical play styles. In the conflict condition where children chose between a same-sex playmate engaged in an other-sex activity or an other-sex playmate engaged in a same-sex activity, boys (both CAH and unaffected brothers) almost exclusively chose playmates based on the preferred play style of the playmate as opposed to the preferred gender label of the playmate. By contrast, unaffected girls used play style and gender label about equally when choosing playmates. Girls with CAH showed a pattern similar to that of boys: their playmate selections were more masculine than unaffected girls, they preferred a boy-typical play style and, in the conflict condition, chose playmates engaged in a masculine activity. These findings suggest that prenatal androgen exposure contributes to sex differences in playmate selection observed in typically-developing children, and that, among boys and girls exposed to high levels of androgens prenatally, play style preferences drive sex segregation in play.

6.

Prenatal Hormones and Postnatal Socialization by Parents as Determinants of Male-Typical Toy Play in Girls With Congenital Adrenal Hyperplasia

Toy choices of 3- to 10-year-old children with congenital adrenal hyperplasia (CAH) and of their unaffected siblings were assessed. Also assessed was parental encouragement of sex-typed toy play. Girls with CAH displayed more male-typical toy choices than did their unaffected sisters, whereas boys with and without CAH did not differ. Mothers and fathers encouraged sex-typical toy play in children with and without CAH. However, girls with CAH received more positive feedback for play with girls’ toys than did unaffected girls. Data show that increased male-typical toy play by girls with CAH cannot be explained by parental encouragement of male-typical toy play. Although parents encourage sex-appropriate behavior, their encouragement appears to be insufficient to override the interest of girls with CAH in cross-sexed toy

7.

Increased aggression and activity level in 3- to 11-year-old girls with congenital adrenal hyperplasia

Experimental research in a wide range of mammals has documented powerful influences of androgen during early development on brain systems and behaviors that show sex differences. Clinical research in humans suggests similar influences of early androgen concentrations on some behaviors, including childhood play behavior and adult sexual orientation. However, findings have been inconsistent for some other behaviors that show sex differences, including aggression and activity level in children. This inconsistency may reflect small sample sizes and assessment limitations. In the present study, we assessed aggression and activity level in 3- to 11-year-old children with CAH (38 girls, 29 boys) and in their unaffected siblings (25 girls, 21 boys) using a questionnaire that mothers completed to indicate current aggressive behavior and activity level in their children.

Data supported the hypotheses that:

  • 1. unaffected boys are more aggressive and active than unaffected girls;
  • 2. girls with CAH are more aggressive and active than their unaffected sisters; and
  • 3. boys with and without CAH are similar to one another in aggression and activity level.

These data suggest that early androgens have a masculinizing effect on both aggressive behavior and activity level in girls.

8.

Prenatal androgen exposure alters girls’ responses to information indicating gender-appropriate behaviour

Individual variability in human gender-related behaviour is influenced by many factors, including androgen exposure prenatally, as well as selfsocialization and socialization by others postnatally. Many studies have looked at these types of influences in isolation, but little is known about how they work together. Here, we report that girls exposed to high concentrations of androgens prenatally, because they have the genetic condition congenital adrenal hyperplasia, show changes in processes related to selfsocialization of gender-related behaviour. Specifically, they are less responsive than other girls to information that particular objects are for girls and they show reduced imitation of female models choosing particular objects. These findings suggest that prenatal androgen exposure may influence subsequent gender-related behaviours, including object (toy) choices, in part by changing processes involved in the self-socialization of gendered behaviour, rather than only by inducing permanent changes in the brain during early development. In addition, the findings suggest that some of the behavioural effects of prenatal androgen exposure might be subject to alteration by postnatal socialization processes. The findings also suggest a previously unknown influence of early androgen exposure on later processes involved in self socialization of gender-related behaviour, and thus expand understanding of the developmental systems regulating human gender development.

9.

How early hormones shape gender development

Highlights
Prenatal androgens influence sex-related characteristics to varying degrees.
• Androgens facilitate male-typed activities through interest in things versus people.
• Androgens are associated with some aspects of brain structure and activation.
• Current work is focused on interplay of hormones and social environment.
• Relevant to questions regarding sex-related psychopathology, prenatal programming.
 
Many important psychological characteristics show sex differences, and are influenced by sex hormones at different developmental periods. We focus on the role of sex hormones in early development, particularly the differential effects of prenatal androgens on aspects of gender development. Increasing evidence confirms that prenatal androgens have facilitative effects on male-typed activity interests and engagement (including child toy preferences and adult careers), and spatial abilities, but relatively minimal effects on gender identity. Recent emphasis has been directed to the psychological mechanisms underlying these effects (including sex differences in propulsive movement, and androgen effects on interest in people vs things), and neural substrates of androgen effects (including regional brain volumes, and neural responses to mental rotation, sexually arousing stimuli, emotion, and reward). Ongoing and planned work is focused on understanding the ways in which hormones act jointly with the social environment across time to produce varying trajectories of gender development, and clarifying mechanisms by which androgens affect behaviors. Such work will be facilitated by applying lessons from other species, and by expanding methodology. Understanding hormonal influences on gender development enhances knowledge of psychological development generally, and has important implications for basic and applied questions, including sex differences in psychopathology, women’s underrepresentation in science and math, and clinical care of individuals with variations in gender expression.

10.

The organizing actions of adolescent gonadal steroid hormones on brain and behavioral development

Highlights

• Adolescence is a sensitive period for the effects of hormones on brain and behavior.
• Testicular hormones masculinize and defeminize social and reproductive behaviors.
• Ovarian hormones have both feminizing and defeminizing effects on female behavior.
• Gonadal steroid hormones drive many brain structural changes during adolescence.
• Adolescence may be part of a protracted postnatal steroid-sensitive period.

Abstract
Adolescence is a developmental period characterized by dramatic changes in cognition, risk-taking and social behavior. Although gonadal steroid hormones are well-known mediators of these behaviors in adulthood, the role gonadal steroid hormones play in shaping the adolescent brain and behavioral development has only come to light in recent years. Here we discuss the sex-specific impact of gonadal steroid hormones on the developing adolescent brain. Indeed, the effects of gonadal steroid hormones during adolescence on brain structure and behavioral outcomes differs markedly between the sexes. Research findings suggest that adolescence, like the perinatal period, is a sensitive period for the sex-specific effects of gonadal steroid hormones on brain and behavioral development. Furthermore, evidence from studies on male sexual behavior suggests that adolescence is part of a protracted postnatal sensitive period that begins perinatally and ends following adolescence. As such, the perinatal and peripubertal periods of brain and behavioral organization likely do not represent two discrete sensitive periods, but instead are the consequence of normative developmental timing of gonadal hormone secretions in males and females.

11.

Effects of chromosomal sex and hormonal influences on shaping sex differences in brain and behavior: Lessons from cases of disorders of sex development

Sex differences in brain development and postnatal behavior are determined largely by genetic sex and in utero gonadal hormone secretions. In humans however, determining the weight that each of these factors contributes remains a challenge because social influences should also be considered. Cases of disorders of sex development (DSD) provide unique insight into how mutations in genes responsible for gonadal formation can perturb the subsequent developmental hormonal milieu and elicit changes in normal human brain maturation. Specific forms of DSDs such as complete androgen insensitivity syndrome (CAIS), congenital adrenal hyperplasia (CAH), and 5α-reductase deficiency syndrome have variable effects between males and females, and the developmental outcomes of such conditions are largely dependent on sex chromosome composition. Medical and psychological works focused on CAH, CAIS, and 5α-reductase deficiency have helped form the foundation for understanding the roles of genetic and hormonal factors necessary for guiding human brain development. Here we highlight how the three aforementioned DSDs contribute to brain and behavioral phenotypes that can uniquely affect 46,XY and 46,XX individuals in dramatically different fashions

Aus der Studie:

CAH ein Schaubild

CAH, CAIS und 5-alpha reductace Deficiency: ein Schaubild

Weiteres aus der Studie:

Research focused on cases of DSD have helped the scientific community better understand the interplay between gonadal hormones and sex chromosome complement with regard to generating some of the sex differences observed in humans. These works have shed light on the likelihood that testosterone exposure, as opposed to sex chromosomes, is a larger contributing factor for guiding one’s sexual orientation and to a lesser extent gender identity. We see that 46,XX CAH individuals that have been exposed to in utero testosterone experience a greater degree of dissatisfaction in gender assignment in addition to above-average levels of homosexual and bisexual fantasies, a proxy for sexual preference. As previously mentioned, other variables are present in CAH cases such as life-long medical interventions and psychosocial confounds. These variables may constitute an environmental factor that, when coupled with biological predispositions, generates variations in sexual orientation and gender identity. That sexual orientation is determined solely by in utero hormonal milieu is unlikely. We see that the vast majority of CAH women, despite having been exposed to above-average levels of testosterone, identify as heterosexual as measured by both partners and sexual fantasies. The science of sexual orientation is still weakly understood at the mechanistic level; however, considerable amounts of research have proposed many possibilities for the causes of same-sex attraction (LeVay, 2012; Bailey et al., 2016).

The strongest evidence that adds support for the influence of testosterone in structuring gender identity comes from the work focused on 46,XY CAIS, in which nearly all individuals researched indicate feelings typical of female gender. In addition to self-reports and clinical evaluations, recent fMRI studies have also demonstrated that CAIS women not only feel female but also neurologically respond more similarly to 46,XX women than to 46,XY men when observing sexual images. However, new studies are continually emerging suggesting that gender identity and sexual orientation in individuals with CAIS are not as clear as once thought, and the rates of nonheterosexual and gender dysphoria may be much higher than currently stated. In addition to CAH and CAIS, 5α-reductase deficiencies have also demonstrated the strong role of testosterone’s ability to organize the human brain hormonally and influence adult gender identity and behavior. If early in utero exposure had no influence in guiding brain gender, we would expect considerable difficulty with the female-to-male transition observed in pubertal years in those with 5α-reductase deficiency. What we observe, however, is that an overwhelming majority of individuals with this condition comfortably transitioned into the new gender role at puberty, a worldwide observation occurring throughout many different types of social environments. Despite the convincing findings for the role of testosterone in generating these observations, the influence of social and other environmental variables are also factors that require consideration.

Cognitive Conclusions
Studying cases of DSDs has also provided insight into some of the biological parameters that generate sex differences in cognitive abilities such as visuospatial awareness and targeting ability. From studies with 46,XX CAH individuals it has been well established that in utero androgen exposure seems to enhance the ability to mentally rotate objects as well as improving hand–eye coordination during targeting tasks. This trait appears to be dependent on sex chromosome complement in addition to hormone exposure, insofar as 46,XY males with CAH actually perform worse than their matched controls, which is unexpected given the fact that CAH males would have equal or elevated levels of circulating testosterone. This raises the notion, as mentioned above, that proper timing and dosage are also likely to be important for enhancing such abilities and that simply having above-average levels of testosterone during development would not generate a “super-male.” CAIS provides another insight into this matter, demonstrating that the ability to respond to testosterone on an XY background is critical to establishing baseline spatial performance abilities. fMRI studies demonstrate that 46,XY CAIS had less inferior parietal lobe neuroactivation when performing spatial rotation tasks, a feature that resembles 46,XX females more than control genetic males. These fMRI studies on CAIS individuals once again minimize social influences and allow for a more unbiased assessment of the requirement for testosterone over genetic composition for shaping these cognitive performance sex differences.
Structural Conclusions
From the MRI studies that have been conducted in patients with CAH, it is clear that DSDs affect more than gonadal development. As highlighted, the central nervous system is highly sensitive to various hormones, and imbalances of these can greatly affect downstream behavior as well as overall brain structure. Variations in amygdala volume seem to be present in some individuals with CAH; however the effect is different depending on sex chromosome composition. Specifically, 46,XY males with CAH show unilateral reductions in the left amygdala, whereas 46,XX females with CAH show bilateral reductions in overall volume. Alterations in amygdala volume seem to be consistent with long-term glucocorticoid replacement therapies because findings for non-CAH patients on such hormone regiments also show amygdala abnormalities. The documentations of white matter irregularities seem to be unaffected by chromosomal sex and to cause similar variations in both males and females with CAH. The explanations for these results are not agreed upon, and more research will be needed before causations can be associated with the unusual white matter findings. Although limited, these discoveries have opened a new area for potential investigation focusing on the role of glucocorticoid influences in the developing brain in addition to the more frequently studied gonadal hormonal contributions. Unfortunately, no extensive structural studies have been conducted in patients with CAIS or 5α-reductase deficiencies. These findings would be invaluable in determining the direct effect of testosterone on the structures that in MRI studies have shown alterations in CAH. Future work focusing on outcomes in individuals with DSD will continue to aid in deciphering the contributions of chromosomal sex and hormones to shaping the sexually dimorphic human brain.

12.

Feminists wrestle with testosterone: Hormones, socialization and cultural interactionism as predictors of women’s gendered selves 

Sociology of gender has developed beyond a personality-centered idea of ‘‘sex-roles’’ to an approach that stresses interaction and social structure. At the same time, there has been a concurrent development in the psychological sex-differences and medical literatures toward including the biological bases of sex-typed behavior and gender identities. In this paper, while we conceptualize gender as a social structure, we focus only on the individual level of analysis: testing the relative strength of (maternal circulating) prenatal hormones, childhood socialization, and the power of expectations attached to adult social roles (cultural interactionist) as explanations for women’s self-reported feminine and masculine selves. Our findings are complex, and support some importance of each theory. Prenatal hormones, childhood socialization, and cultural interactionism were all influential factors for gendered selves. While cultural expectations predicted only feminine selves, prenatal hormones were more robust predictors of masculine sense of self. While personality may be a relatively stable characteristic influenced by the body and childhood socialization, our results reinforce the importance of studying how the social world responds to and reinforces gendered personality.

12.

Genetic association suggests that SMOC1 mediates between prenatal sex hormones and digit ratio

Abstract

Men and women differ statistically in the relative lengths of their index and ring fingers; and the ratio of these lengths has been used as a biomarker for prenatal
testosterone. The ratio has been correlated with a wide range of traits and conditions including prostate cancer, obesity, autism, ADHD, and sexual orientation. In a genome-wide association study of 979 healthy adults, we find that digit ratio is strongly associated with variation upstream of SMOC1 (rs4902759: P = 1.41 9 10-8) and a meta-analysis of this and an independent study shows a probability of P = 1.5 9 10-11. The protein encoded by SMOC1 has recently been shown to play a critical role in limb development; its expression in prostate tissue is dependent on sex hormones, and it has been implicated in the sexually dimorphic development of the gonads. We put forward the hypothesis that SMOC1 provides a link between prenatal hormone exposure and digit ratio.

Anmerkung: Finde ich interessant: Wenn das Protein, welches Einfluss auf die Entwicklung der Gliedmaßen hat, wiederum abhängig von Testosteron ist, dann würde das durchaus erklären, warum die Digit Ratio ein Indikator  für pränatales Testosteron ist, es könnte je nach Zusammenspiel auch zeigen, warum es ein teilweise unzuverlässiger Anzeiger ist, eben weil die Mechanismen unterschiedlich sind.

13.

Exposure to prenatal life events stress is associated with masculinized play behavior in girls

Previous research has shown that prenatal exposure to endocrine-disrupting chemicals can alter children’s neurodevelopment, including sex-typed behavior, and that it can do so in different ways in males and females. Non-chemical exposures, including psychosocial stress, may disrupt the prenatal hormonal milieu as well. To date, only one published study has prospectively examined the relationship between exposure to prenatal stress and gender-specific play behavior during childhood, finding masculinized play behavior in girls who experienced high prenatal life events stress, but no associations in boys. Here we examine this question in a second prospective cohort from the Study for Future Families. Pregnant women completed questionnaires on stressful life events during pregnancy, and those who reported one or more events were considered “stressed”. Families were recontacted several years later (mean age of index child: 4.9 years), and mothers completed a questionnaire including the validated Preschool Activities Inventory (PSAI), which measures sexually dimorphic play behavior. In sex-stratified analyses, after adjusting for child’s age, parental attitudes towards gender-atypical play, age and sex of siblings, and other relevant covariates, girls (n=72) exposed to prenatal life events stress had higher scores on the PSAI masculine sub-scale (β=3.48, p=0.006) and showed a trend towards higher (more masculine) composite scores (β=2.63, p=0.08). By contrast, in males (n=74), there was a trend towards an association between prenatal stress and higher PSAI feminine sub-scale scores (β=2.23, p=0.10), but no association with masculine or composite scores. These data confirm previous findings in humans and animal models suggesting that prenatal stress is a non-chemical endocrine disruptor that may have androgenic effects on female fetuses and anti-androgenic effects on male fetuses.

Anmerkung: Die Werte sind allerdings anscheinend sehr gering

14.

Relations between prenatal testosterone levels and cognitive abilities at 4 years.

Relations between prenatal testosterone (T) levels and cognitive abilities at age 4 were examined for 28 girls and 30 boys. Prenatal T levels were measured in 2nd trimester amniotic fluid samples obtained by amniocentesis and were examined in relation to scores on tests of cognitive abilities. For girls, prenatal T levels showed a curvilinear (inverted U-shaped) relation to language comprehension and classification abilities. Linear relations also were observed in that prenatal T levels were inversely related to girls‘ scores on tasks assessing counting and number facts. Similarly, girls with high average block building scores had lower prenatal T and cognitive abilities were not observed. The observation of relations in girls and not boys is discussed, and the findings are examined in relation to theories of hormone-behavior relations.

15.

Relations between prenatal testosterone and cerebral lateralization in children.

Several theorists have proposed that the sex steroid testosterone acts on the fetal brain during a critical period of development to influence cerebral lateralization (N. Geschwind & A. M. Galaburda, 1987; M. Hines & C. Shipley, see PA, Vol 71:8996; S. F. Witelson, see PA, Vol 79:26441. In the present study. relations were examined between prenatal testosterone levels in 2nd trimester amniotic fluid and lateralization of speech, affect, and handedness at age 10. Girls with higher prenatal testosterone levels were more strongly right-handed and had stronger left-hemisphere speech representation. Boys with higher prenatal testosterone levels had stronger right-hemisphere specialization for the recognition of emotion. This pattern of results is most consistent with Witelson’s (1991) claim that prenatal testosterone leads to greater lateralization of function.