Technisches Verständnis, Berufwahl und Testosteron

Eine Theorie zu den Geschlechterunterschieden besagt, dass pränatales Testosteron und später auch postnatales Testosteron das Gehirn auf eine bestimmte Weise formatiert, die eben auch zu verschiedenen Fertigkeiten führt.

Ich hatte hier schon einmal eine Metastudie zitiert, die folgende Unterschiede festgestellt hat:

Es zeigen sich durchaus deutliche Unterschiede im sprachlichen Bereich (Spelling – 0,45 Language 0,40); Mechanical Reasoning (+0,76), Spatial perception (+0.44); Mental rotation (+0.73); Sexuality: Masturbation (+0.96) Sexuality: Attitudes about casual sex (+0.81); Agreeableness: Tendermindedness (-0.91);

Hier soll es insbesondere um die Eigenschaften gehen, die in einem Zusammenhang mit Technik stehen. Dabei zunächst zu dem Wert von 0,76 bei „Mechanical Reasoning“ eine graphische Darstellung einer solchen Effektstärke (im Bild nur 0,73):

Hier sieht man recht gut, dass gerade in den oberen Bereichen, also denen, die in diesem Bereich eine besondere Stärke haben, Männer zahlenmäßig weitaus stärker vertreten sind. Bei Sprachen wäre dies entsprechend anders herum. Dies zeigt auch, dass es Frauen gibt, die genau so gut in diesen Bereichen sind, aber eben zahlenmäßig deutlich weniger um so größer die Verschiebung ist.

Ein Hinweise darauf, dass dies mit biologischen Faktoren zusammenhängt, insbesondere mit Hormonen geben die „CAH-Frauen„, also Frauen, die aufgrund einer Fehlfunktion der Nebennierenrinde deutlich mehr Testosteron produzieren als andere Frauen.

Diese haben ein stärkeres Interesse an den klassischen MINT-Fächern:

The rare genetic condition congenital adrenal hyperplasia (CAH) boosts androgen hormone exposure in the womb. Women with CAH have stronger interest in science, technology, engineering and mathematics (STEM) careers than women who have normal hormone levels. CAH does not appear to influence male career interests.

Der Grund hierfür könnte eben eine andere Gehirnformatierung aufgrund des pränatalen Testosterons sein:

A battery of tests was administered to 17 patients with congenital adrenal hyperplasia (CAH) and 17 normal controls to investigate the effect of prenatal androgen exposure on cerebral lateralization and cognitive performance. Individuals were compared on measures of hand preference, verbal and performance IQ, and temporal processing asymmetry. A higher incidence of left-handedness was found among CAH participants. CAH individuals exhibited higher performance IQs as opposed to verbal IQs. Temporal processing asymmetries were investigated using an auditory gap detection task. Measures of reaction time and response error revealed a right-ear, therefore left-hemisphere, advantage for gap detection. This right-ear advantage did not differ between CAH individuals and controls. Results partially support the hypothesis that prenatal androgen exposure causes a shift in cerebral lateralization toward right-hemisphere dominance.

Testosteron scheint auch allgemein das räumliche Denken, welches mit diesen Bereichen in Verbindung steht, zu fördern:

It has been proposed that exposure of the central nervous system to high concentrations of androgens during sensitive periods in early development may facilitate the ability to process spatial information. Most tests of this proposal have been derived from nonhuman species. To test this hypothesis in humans, we evaluated spatial reasoning in preadolescent children with congenital adrenal hyperplasia (CAH), a condition characterized by elevated androgens during gestation. The Primary Mental Abilities (PMA) Spatial Relations test was administered to 12 children with CAH (7 girls, 5 boys) and 10 unaffected sibling controls (6 girls, 4 boys), ranging in age from 8 to 12 years. Results showed a significant interaction between sex and clinical status. Girls with CAH achieved significantly higher spatial scores than control girls, whereas boys with CAH showed significantly lower spatial scores than control boys.

On the PMA Perceptual Speed test, given for comparison, girls with CAH scored significantly lower than control girls, producing a double dissociation. The results demonstrate that group differences in spatial proficiency can be detected in preadolescent children with CAH. The findings replicate and extend results reported previously by Resnick, Berenbaum, Gottesman, and Bouchard (1986), and are consistent with an organizing effect of early androgens on brain areas subserving spatial processes.

Und noch eine Studie in die gleiche Richtung:

Administered a cognitive test battery that emphasized spatial ability, verbal fluency, and perceptual speed and accuracy to 17 females (aged 12.7–23.2 yrs) and 8 males (aged 13–29.9 yrs) with congenital adrenal hyperplasia (CAH) and 13 normal female relatives (aged 11.4–31.1 yrs) and 14 unaffected male relatives (aged 12.5–28.8 yrs). In addition, 13 fathers and 15 mothers of CAH patients participated. Ss also completed the Progressive Matrices, a vocabulary test, and an early life activities questionnaire (ELAQ). Findings indicate that CAH females, as compared with normal females, showed significantly enhanced performance on hidden pattern, card rotation, and mental rotation tests of spatial ability. On the ELAQ, CAH females, relative to normal females, showed significantly lower frequencies of participation in activities involving verbal expression and a trend toward greater participation in spatial manipulation activities. However, differences between CAH females and normal females in early childhood activities did not account for observed differences in spatial ability, given the absence of a significant correlation between the spatial manipulation activity scale and spatial ability. There was an absence of reliable differences between male CAH patients and controls across spatial tasks. Results are consistent with an effect of pre- and perinatal androgenizing hormones on the development of spatial ability. (58 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)

Eine andere Studie sieht einen Zusammenhang zwischen dem Wunsch zu konstruieren oder Konstruktionen zu analysieren und pränatalen Testosteron:

This study examines foetal testosterone (fT) levels (measured in amniotic fluid) as a candidate biological factor, influencing sex differences in systemizing. Systemizing is a cognitive process, defined as the drive to analyze or construct systems. A recent model of psychological sex differences suggests that this is a major dimension in which the sexes differ, with males being more drawn to systemize than females. Participants included 204 children (93 female), age 6–9 years, taking part in a long-term study on the effects of fT. The systemizing quotient – children’s version was administered to these mothers to answer on behalf of their child. Males (mean = 27.79 ± 7.64) scored significantly higher than females (mean = 22.59 ± 7.53), confirming that boys systemize to a greater extent than girls. Stepwise regression analysis revealed that fT was the only significant predictor of systemizing preference when the sexes were examined together. Sex was not included in the final regression model, suggesting that fT levels play a greater role than the child’s sex in terms of differences in systemizing preference. This study suggests that the levels of fT are a biological factor influencing cognitive sex differences and lends support to the empathizing–systemizing theory of sex differences.

Eine weitere behandelt den Zusammenhang von räumlichen Denken und dem technischen Verständnis:

In three experiments we tested the effects of spatial visualization ability on performance of a motion-verification task, in which subjects were shown a diagram of a mechanical system and were a~ked to yerify a sentence stating the motion of one of the system components. We propose that this task Involves component processes of (1)sentence comprehension, (2) diagram compre- ~ension, (3) text-diagram integration, and (4)mental animation. Subjects with low spatial ability made more errors than did subjects with high spatial ability on this task, and they made more errors on items in which more system components had to be animated to solve the problem. In contrast, the high-spatial subjects were relatively accurate on all trials. These results indicate that spatial visualization is correlated with accuracy on the motion-verification task and suggest that this correlation is primarily due to the mental animation component of the task. Reaction time and eye-fixation data revealed no differences in how the high- and low-spatial subjects decomposed the task. The data of the two groups of subjects were equally consistent with a piecemeal model of mental animation, in which components are animated one by one in order of the causal chain of events in the system.

Natürlich könnte auch Selbstvertrauen und eben der Stereotyp Threat dafür verantwortlich sein. Eine weitere Studie beleuchtet dies näher:

Compared spatial-mechanical skills and mathematics self-confidence as mediators of gender differences in mathematics. 187 8th grade students (aged 13.3-14.8 yrs) completed: (1) the Vandenberg Mental Rotation Test; (2) the Mechanical Reasoning subtest of the DAT battery (G. Bennett et al, 1990); (3) the Water Levels Test (M. Sholl, 1989); (4) 3 spatial-mechanical reasoning measures; (5) academic self-confidence measures; and (6) male and female subtests of the 3rd International Mathematics and Science Study (TIMSS). Results show that significant correlations between gender and mathematics performance, favoring males. A spatial-mechanical composite accounted for 74% of the total indirect effects, whereas mathematics self-confidence accounted for 26%. By 8th grade, female Ss‘ relatively poorer spatial and mechanical skills contributed to lower scores on types of mathematics at which male Ss typically excelled.

Feingold beleuchtet die Geschlechterunterschiede über die verschiedenen Altersstufen:

Gender differences in cognitive abilities were determined using the norms from the four standardizations of the Differential Aptitude Tests conducted between 1947 and 1980, and from the four standardizations of the Preliminary Scholastic Aptitude Test/Scholastic Aptitude Test conducted between 1960 and 1983. The standardized gender differences (d s) were averaged over grade of examinees and year of standardization to obtain a mean effect size for each ability, and variations among effect sizes were examined for grade, year, and Grade × Year trends. Girls scored higher than boys on scales of grammar, spelling, and perceptual speed; boys had higher means on measures of spatial visualization, high school mathematics, and mechanical aptitude; and no average gender differences were found on tests of verbal reasoning, arithmetic, and figural reasoning. Gender differences declined precipitously over the years surveyed, and the increases in these differences over the high school grades have diminished. The important exception to the rule of vanishing gender differences is that the well-documented gender gap at the upper levels of performance on high school mathematics has remained constant over the past 27 years.

Eine Auswertung der amerikanischen SAT geht in die gleiche Richtung:

For over 20 years, above-level testing with the College Board Scholastic Aptitude Test (SAT) has been used to assess the abilities of well over 1 000 000 highly able 12–13-year-olds (students in the top 3% in intellectual ability). In this population, the predictive validity of the mathematical part of the SAT, SAT-M, for academic and vocational criteria has been demonstrated over 10-year gaps. Here, we document aspects of the psychological and achievement profiles of these highly able students, paying particular attention to sex differences. Males score higher on SAT-M (i.e., mathematical reasoning ability) than females; this difference is accompanied by differences between the sexes in spatial–mechanical reasoning abilities and in a number of lifestyle and vocational preferences. Collectively, these attributes appear to play a key role in structuring male–female disparities in pursuing advanced educational credentials and careers in the physical sciences. After profiling a number of the behavioural characteristics of the highly able, we examine some underlying biological correlates of these phenotypic manifestations. These include hormonal influences, medical and bodily conditions and enhanced right hemispheric activation.

Interessantes zu diesen Unterschieden  in „A Tale of two hormones“ von Patricia Hausmann (PDF):

Sie stellt dar:

  • das vieles dafür spricht, dass Frauen nicht in die technischen Berufe, insbesondere solche die räumliches Denken erfordern, gehen, weil sie dies nicht wollen, nicht weil sie davon abgehalten werden
  • Sie stellt dar, dass Männer eher theoretische Fächer und Frauen eher soziale/ästhetische Fächer wählen.
  • sie stellt dar, dass selbst Frauen, die mathematisch begabt sind, eher soziale oder sprachliche Fächer wählen, da sie in diesen meist auch begabt sind und diese sie mehr interessieren.
  • sie stellt dar, dass es nicht an der Wissenschaft an sich oder dem rauhen Klima dort liegen kann: Die Frauen, die aus den STEM-Fächern verschwanden, haben sich häufig anderen Wissenschaftsbereichen zugewandt.
  • sie verweist darauf, dass Theorien, die die Unterschiede mit Vorurteilen und gesellschaftlicher Abschreckung erklären nicht erklären können, warum Mädchen häufig bis zum Einsetzen der Pubertät in diesen Fächern nicht hinterher hängen, dann aber mit den Pubertät und den Hormonen ein entsprechender Wandel eintritt.
  • sie verweist darauf, dass auch spätere Testosterongaben das räumliche Denken bei Frauen verbessern und ihre sprachlichen Fähigkeiten verschlechtern.

Eine lohnenswerte Darstellung auf ca. 5 Seiten.

Ein weiterer Artikel beleuchtet die Motive der Mädchen, bestimmte Karrierewege nicht einzuschlagen:

When she examined why students elected to take advanced math and physics courses in high school, she found that they did not base their selections on the obvious factors, such as what courses they liked. Instead, utility mattered most. „How important was the course to their long-term goals?“ she says. „Already in high school, they’ve made decisions about what they want to do later.“

And mathematically talented girls took themselves out of the physics-engineering pipeline for much the same reasons that Mr. Stanley enumerated. „The females are more likely than the males to say they want a job where they can help other people,“ Ms. Eccles says. „Males are more likely to say they want a job where they can be their own boss and make lots of money.“ As a result, many young women with high math skills in her study ended up studying biology instead of physics or engineering.

But unlike Mr. Stanley, Ms. Eccles sees room to change the interest gap, by educating students better about career choices. „You have to change their views of these professions,“ she says. „Engineers do help people. Physical scientists do help people. We’ve got to get a lot more information to high-school kids about what the physical sciences are like.“

Meiner Meinung nach wird ein Hinweis darauf, dass auch Ingenieure Menschen helfen, nicht viel nützen. Denn es dürfte eben um den direkten Umgang mit Menschen gehen, das Gefühl mit diesen zu arbeiten und ihnen dabei zu helfen, nicht das abstrakte Helfen indem man ein technisches Produkt verbessert.

Helen Fisher et al gehen noch einmal auf die Digit Ratio und Verhalten ein :

Constellations of biobehavioral traits are associated with activity in the testosterone and estrogen systems, due to fetal priming or hormonal alterations during the life course. Using these data, we developed two 14-item measures to investigate the traits associated with these hormone systems. To reach adequate internal consistency, we used participants of an Internet dating site; the final sample was 39,913 individuals. Factorial structure and correlations with several validating criteria were consistent with the hypothesis that these scales measured these neurochemical systems (Fisher, 2009; Fisher et al., in preparation). Two of these validity measures are discussed: gender loading of each scale; and degree to which members of each scale pursued particular occupations. Then we investigated the hypothesis that individuals scoring high on either of these scales also expressed a specific second to fourth digit ratio of the right hand. Individuals who reported a longer 4th finger relative to 2nd expressed high scores on the proposed testosterone scale; individuals who reported a longer 2nd finger relative to 4th or 2nd and 4th digits of equal length expressed high scores on the proposed estrogen/oxytocin scale. These data are consistent with the hypothesis that these 2D:4D ratios are artifacts of hormonal priming in utero.

Aus der Studie:

We predicted that those who scored highest on the proposed testosterone scale would be the most likely to pursue a career in engineering or an analogous math-based occupation. We had also predicted that those who scored highest on the proposed estrogen/ oxytocin scale would be the most likely to pursue a career in teaching, social work, or profession focused on social advocacy. Self-report information regarding occupation was provided in a free text field, and a participant was designated as a ‘‘teacher” if the text field included the string ‘‘educat” or ‘‘teach.” A participant was designated as an ‘‘engineer” if the text field included the string ‘‘engineer.” In the sample of 39,913 participants, 16,382 completed the ‘‘occupation” field. Of these, 3.1% were teachers and 2.1% were engineers by our criteria. The ‘‘teachers” obtained a mean score of 27.5 on the proposed estrogen/oxytocin scale vs. a score of 24.8 obtained by engineers, t = 7.68, df = 852, p < .001, eta = .25. Teachers obtained a relative mean score of 23.1 on the proposed testosterone scale vs. a score of 28.1 obtained by engineers, t = 14.44, df = 852, p < .001, eta = .44. As predicted, teachers scored higher than engineers on the proposed estrogen/oxytocin scale and engineers scored higher than teachers on the proposed testosterone scale. This effect was partly due to gender. In this sample, 81.1% of the engineers were men and 79.0% of the teachers were women. However, the effect was still seen when men and women were examined separately. Among males, mean scores were 28.6 on the proposed testosterone scale for engineers vs. 25.5 for teachers, t = 5.80, df = 384, p < .001, eta = .28. Female engineers scored 25.7 on the proposed testosterone scale vs. 22.4 for female teachers, t = 4.96, df = 466, p < .001, eta = .22. On the proposed estrogen/oxytocin scale, female teachers scored 27.5 vs. 25.5 for female engineers, t = 3.15, df = 466, p < .01, eta = .14; male teachers scored 27.1 vs. 24.7 for male engineers, t = 4.35, df = 384, p < .001, eta = .22.

Zur Variabilität und den zeitlichen Entwicklungen

This study addresses developmental trends in gender reality for 6–17 year-old children (a total of 16,322 males and 15,412 females) in Taiwan. Typically, large, representative and normative data sets for 11 cognitive and affective tests were analyzed. Results revealed that gender differences in personality, interest, and learning styles were fairly stable across age levels. Cognitive advantages for each gender, however, varied with developmental phase. The hypothesis of “greater male variability” was supported in most domains. Consideration of compounded and accumulative effects may be crucial for explaining gender reality in outcome behaviors and career choices.

Und noch eine Studie zu den Digit Ratios bei Mathematikstudenten:

This study found evidence that female pre-service teaching students who were inclined toward mathematics exhibited smaller, more masculine, digit ratios than those who were not as mathematically inclined. The right-hand 2D:4D ratios of the female pre-service teaching students who had a mathematics major or minor as their chosen field of study were compared to the right-hand 2D:4D ratios of the female pre-service teaching students who did not have a mathematics major or minor as their chosen field of study. The 2D:4D ratios of those with the mathematics major or minor was found to be statistically significantly less than those without.

Also männlichere Digit Ratios bei Mathemathikstudentinnen, um so weiter um so niedriger.

Bei Programmieren das gleiche Bild:

Being able to use information communication technology (ICT) effectively has become an essential element of participation within an increasingly digital culture. However, there are differences in participation within this digital culture. Prenatal testosterone exposure is thought to influence the development of numeric capabilities and relate to levels of anxiety, both of which contribute towards engagement with ICT. This study examined whether an index of prenatal exposure to testosterone, digit ratio (2D:4D), is related to successful involvement within a computer-technology context – performance in a Java programming course. Three studies (N = 73,75,65) identified a consistent negative correlation between 2D:4D digit ratio and attainment (r ≈ −0.2). A fourth study (N = 119) found that 2D:4D digit ratio positively correlated with two indices of computer-related anxieties, as well as anxiety sensitivity (r = 0.32/0.51). These results suggest that males and females who have been exposed to higher levels of testosterone within the womb perform better upon academic assessments of Java-related programming ability within computer science education, and have lower levels of computer-related anxieties outside computer science education. Thus, the 2D:4D index of prenatal testosterone exposure correlated with the two factors that directly impact upon ICT engagement, which is increasingly essential to effectively participate within educational and occupational environments.

Eine etwas ungeordnete Sammlung. Aber immerhin ein Anfang. Es sind denke ich einige interessante Studien dabei, die durchaus bestätigen, dass die Berufswahl biologische Hintergründe und Männer und Frauen im Schnitt verschiedene Eigenschaften haben.

Gegenstudien sind wie immer herzlich willkommen!