Gender differences: Asya Kazantseva about male and female brain
The human brain is not fully understood, giving rise to numerous speculations. Is homosexuality a social construct or due to innate factors? As sexual difference is manifested at the level of the brain.
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In order to talk about men and women, you need to try to understand, than they differ from each other, and what determines the formation of sex. We all used to think that at the moment of conception in the ovum with X chromosome gets sperm with either X chromosome or Y chromosome, and only depends on, it's a boy or a girl. Nothing will change, everything is already predetermined. In fact, fertilization is only the first stage of sex determination, and then there are other stages, and between them is possible misalignment. And so real man and real woman is only an extreme form of the continuous spectrum, which gives you many different options.
At the moment of conception we have genes, chromosomes men or women chromosome or some kind of unusual, an intermediate set of chromosomes, but then should turn on endocrine glands, which normally develop as female, and only in the case if you have a Y chromosome, it produced proteins can begin to form the male endocrine glands. If this happens, then begins to form male anatomy — this occurs on the second, third, fourth month of pregnancy. If produced male hormones, androgens, they affect brain development, this occurs from the fourth to the seventh months of pregnancy. The anatomical differences between men from women from the point of view of the brain is laid in this period, and in a very small extent, continue to form after birth. And after that is influenced by social aspects.
What happens during conception? The woman is a person whose sex chromosomes XX, male is the man who has the sex chromosomes XY. Accordingly, all female egg always has X chromosome and the sperm are divided 50 to 50, half of the spermatozoa have the X chromosome and the other half are Y, and the sperm fertilizes the egg, depends on who will turn out a boy or a girl. On this subject there is a lot of speculation about whether it is possible to affect which sperm fertilizes the egg, you can choose a boy or a girl.
Yes, you can, but in order to do this reliably and scientifically accurate, you will need preimplantation genetic diagnosis. That is, when you do in vitro fertilization in the laboratory, during which each embryo take a few cells and see which genes they have. This is done in order to prevent genetic diseases. In Russia, the law forbids to choose who you want, a boy or a girl, but there are all sorts of workarounds. You can order a genetic analysis of some diseases for your four embryos that you have, you tell me, what are the sex chromosomes, and then you state: "I Want the embryo number two!". Technically the doctors will not be a reason to refuse you.
"For the formation of male or female anatomy genes directly is not important, important is testosterone important androgens".What happens next? When you have conceived, your embryo, formed the basic and absolutely the same for all the gonads. It's called simply the gonad, because no one knows what it will make. Going from her Volfova ducts, Mullerova ducts, some of them can develop in the seminiferous channels, others may develop in the fallopian tubes, but so far that is the basic version of the person.
And further, if nothing happens, the base version will develop like a woman, because every person by default is female. If you have a Y chromosome, and if it produces a special protein, called factor regression Mullerova ducts, under the influence of this protein disappear Mullerova ducts, which would have to be fallopian tubes. The body begins the differentiation of male type.
That is, the normal basic model of man becomes a man. For example, in the future will be hypertrophy of the clitoris, and instead will be a penis and labia instead of scrotum will (if there is a Y-chromosome, and it works). Accordingly, if there is a Y-chromosome, then around the beginning of the second month of pregnancy this underlying gonad becomes a testis and begins to produce androgens — male sex hormones. And under the action of male sex hormones starts weight changes in anatomy. That is, if she starts to produce androgens, then, accordingly, the reproductive system develops in such a way that man becomes man. But it is important to note that a very different options. Perhaps someone with a Y chromosome, but the protein is somehow not affected, or affected later, began to produce sex hormones, but the cells are not sensitive to them. And perhaps that person is a girl, but the body somehow increased levels of androgens, and so it becomes masculine.
It is important that for the formation of male or female anatomy genes directly is not important, important is testosterone important androgens. That is, what would you have had the genes, the question is, do you have certain hormones. If you have a hormones for men, you will become anatomically a man, if you don't have male hormones that a man you will not ever. And there are all sorts of interesting consequences.
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There are various options. If the person genotype is XY, but testosterone is not produced or it is produced but cells are not sensitive to it, then it turns out the man who looks like a woman, although this man from the point of view of genetics. This is a man with the syndrome of testicular feminization, the cells do not respond to the signal, which comes from androgen, and so it develops as a woman looks like a woman. However, unfortunately, he usually can not have children, although the doctors are looking for ways to help them, and sometimes it works.
And sometimes Vice versa: you have a female genotype, but there are parallel to another disease (congenital adrenal hyperplasia)[https://ru.wikipedia.org/wiki/врожденнаягиперплазиякоры_надпочечников). That is, adrenal glands are enlarged, they are very intense and will among other things produce androgens. Androgens act on the developing embryo, a little girl, he grows up not quite a boy, but, nevertheless, a man, quite a man.
As for the brain — here is a small quote from a great review: "on average, men have more gray matter in the amygdala, hippocampus, anterior part parahippocampal gyrus, posterior cingulate, breakline, shell, front part of the temporal lobe, some areas of the anterior cingulate cortex of the left hemisphere, some areas of the cerebellum. Is a translation with reductions and simplifications! — Women (also average) more gray matter in certain areas of the frontal cortex, inferior frontal gyrus, some parts of the Wernicke area, parietal tyre, anterior cingulate gyrus, insular cortex, some parts of primary auditory cortex, the thalamus, breakline, left parahippocampal gyrus and some of the sections of the occipital cortex". Whose brain is better? The important thing is that there are quite a few differences, but not about all of these differences, it is clear how they are generally statistically significant because studies are often conducted, for example, on small samples, and individual variability can be more than Majorova. Besides, it's not clear which of these differences matter, and which are not. The brain not only thinks, he also continuously processes information from the senses and from the body, and we are not always aware. And it is not necessary that any increased inferior frontal gyrus will lead to the fact that there will be some differences in behavior or differences in intelligence.
"There is no direct relationship between brain size and intelligence, otherwise whales would be smarter than us."If we take any anatomical feature of the brain, it is likely that we will not be able to find what it affects. There are differences about which we assume that they affect. So here it is impossible a priori to say that someone's brain is better because they differ in dozens of different departments. But any conclusions in principle it is possible to do. If we say, for example, that in men the brain is more — Yes, men have the larger brain. The average weight of the brain of men 1,345 grams, the average weight of the brain women — 1222 grams. But, first, it is clear that we are talking about an average, and thus, individual variation can be very large. And if that's to point a finger at any individual woman, it is quite possible that her brain more than any single man. And, secondly, there is, in fact, a very direct connection between brain size and intelligence, otherwise whales would be smarter than us. I is quite obvious that whales are smarter than us: at least we have built Moscow, and they are not. But, women have more brain in relation to body weight. In addition, the female brain better blood circulation.
But there are, nevertheless, areas where there are pronounced differences between the brains of men and women brain. And there is some evidence to suggest that it might have to do with anything. In particular, we have the hypothalamus. This is a very important control center in the brain, which regulates our entire endocrine system, including sexual behavior. In the hypothalamus there is an area called the SDN, sexually dimorphic nucleus, the core of sexual dimorphism. And men this core is two times more than women; it contains twice as many cells. It's pretty generally accepted information that was confirmed quite a large number of autopsies of the brain. I mean, really, men it's big, it has a lot of cells, in women it is small, it has less cells. DIC Swab in one of the reviews claims that in fact all human beings are born with a fairly large nucleus, and then in women it decreases in the first two to four years of life. But two to four years — it's still pretty early here still difficult to talk about what their programmed society.
What causes homosexuality?There are a number of speculations that at men-homosexuals are the core of the sexual dimorphism is also reduced, as in women, and that's why they like men. But actually it is not very reliable, because there are, for example, a study Livia, who has studied 41 people and showed that gay men this nucleus in the hypothalamus less. But then there was the other opening, which difference is either not found or is insignificant. It is known that in animals the size of kernel is indeed linked to sexual orientation. For example, very widespread homosexuality in sheep. Approximately eight percent of rams never sleep with the females, and only sleep with males. And so these animals do areas closer to the female. It is also known that from a ferret to do a gay if he these areas to destroy.
If we are talking about homosexuality, it is important to understand that this is not a binary characteristic, not black or white, you cannot say that a man is either gay or heterosexual. In fact, there are really people who are totally homosexual, there are people who are absolutely heterosexual, but not very much. There's the famous Kinsey scale, the American sexologist who has studied the sexual behavior of people. And he made this test, where zero means you completely heterosexual, that you have never looked at people of the same sex with an erotic some thoughts that you were not even Platonic, romantic loves that you never see porn with them that they are not interested in any way, and you don't like even the thought of having to touch them.
It is followed by another level — when you mostly prefer people of the opposite sex, but, in principle, for example, in adolescence, loved by person of same sex romantic attachment. Or, for example, you agree to watch pornography, in which there are three, and the two of them. Well, or maybe you have even kissed someone. Sometimes people are predominantly heterosexual, but allows for the possibility to sleep with someone of your gender, if he gets the opportunity. Is the middle, when a person, in General, all the same: to sleep with men or with women who have, that is. But and then, accordingly, homosexuality may also be more or less pronounced. The same person can prefer mostly people of the same sex, but if can sleep with someone of the opposite. It happens that the person prefers people of their own sex is very pronounced, with people of the opposite sex did not sleep, but allows for such a possibility, he likes them sometimes.
And it happens that one is completely homosexual, and people of the opposite sex it does not matter. And that is where you are on this scale, as now considered, to a large extent depends on innate features. So if we're talking about "propaganda of homosexuality", which is so fond of St. Petersburg Deputy Milonov, it is to be and may in part affect those who are on the lines of one to five, in terms of the frequency of their novels with boys or girls.
However, the promotion of sexual orientation — homosexual or heterosexual — would not alter your nature: you still the same way will often like boys, so often will like girls. Max it will affect whether you want it to be, and to what extent. If you are a true congenital homosexual person, what you do, what the propaganda no show, you will still strive to find people of the same sex, to sleep, to love, to live.
But if you are absolutely heterosexual, the same as you, nor persuade you on someone of your gender will never see. Today accumulated quite a lot of evidence that homosexuality is largely innate property. We said that from anatomic differences, there are some disputes, but there is more proven data about differences in the physiology of the brain.
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For example, the Karolinska Institute, the same one that picks Nobel laureates. It is on this subject quite a large research division. For example, they found that if a person in comparision, and in the right hemisphere works more actively, the amygdala, that person will prefer women, and it doesn't matter whether he gay or is he a heterosexual man. Just by looking at his brain, we can say that this brain usually likes women. But if a clear difference between the hemispheres is not, and the amygdala more active work in the left hemisphere, then the person prefers men, regardless of whether it is a homosexual male or a heterosexual woman is.
Even more interesting things came to light when another group of subjects at the same University driven into the scanner, where they show them male and female pheromones. It turned out the following: if you like men, regardless of whether you are male or female, the brain areas associated with sexual behavior, are activated in response to the presentation of male pheromones. But if you like women, no matter you are a woman or a man, then you have these areas of the brain are activated in response to the presentation of female pheromones. And it is important that these are things that cannot be changed by education. These are things that are formed in embryogenesis. That is, while the brain is even formed in the womb, you have already been laid on what pheromones you are going to react, what size you have, the amygdala, and what you will have the lateralization of the hemispheres. No propaganda here, nothing can not do.
But it's also important to understand that "innate" doesn't necessarily mean "genetic". Yes, indeed, there are genes that are associated with homosexuality. But there are environmental conditions that are associated with homosexuality. We are talking thus about the environmental conditions that affected the stage of embryonic development. That's about male homosexuality are known, for example, now such things: the man increases the likelihood of becoming a homosexual, if, first, it has differences in the plot of Xq-28 on the X-chromosome. There is no specific genes, but it is known that the sequence of nucleotides in this area is somewhat different from gay men and men-heterosexual. And here the question arises: why is it not weeded out by natural selection, why, if we have genes that cause homosexuality, they after so many generations of our evolution continue to persist, if homosexual people, as a rule, do not leave offspring, what's the matter?
On this subject there is the following: it turned out that when these genes fall to the man in the body, they increase the likelihood of his homosexuality, but when they enter the body to the woman, they enhance its ability to reproduce. These women get pregnant easier, easier carrying, easier, and maybe even more like children. At least according to family research it turns out that women with such features of the X chromosome children more on average statistically. Scientists at the University of Padua watched the women relatives of gay men, and found that female relatives of gay men on average give birth to more children. There are genes that increase the ability to reproduce, and the man, greatly reduces the opportunity to reproduce. But, nevertheless, women's kompensiruet, and thus the genes persist in the population.
There is another interesting hypothesis: the probability of being gay increases in case of stress, who have experienced the mother during pregnancy. Because of the stress any biological substance reduced level of activity of all sex hormones. That is, in itself, increase the level of cortisol, a stress hormone is a signal for all ovaries and all the eggs, all of the sexual glands that is necessary to dim the activity, because it is not to love, to live, to flee and escape. Therefore, if a pregnant woman an increased level of cortisol, this cortisol crosses the placenta into the body of her son, whom she is pregnant, and to suppress the production of androgens. And if this happens in the last trimester of pregnancy, when he formed boy brain, it can be formed to a lesser extent not so expressed.
"Hitler tried to fight the gays, but because of his actions of gays in Germany became more".About it there are a lot of experiments on animals, for example, they are made in Novosibirsk. There is Tamara Amstislavsky that takes in pregnant rats, concludes the rats in a cage, shines on them bright light, otherwise they stressedout. In the cage — I mean in a very small close where the rat is unable to move, to do anything. In General, rats are experiencing severe stress, and then have their pups born-sons is often seen homosexual behaviour. Pregnant human women no, thank God, were not specially stresseraser, however, there is statistical evidence that, for example, in Germany in 1944-1945 were born more gay than before, and more gay than after. The percentage is more significant proportion of men were gay. But because, of course, Germany 1944-1945 is not the best place and time to be pregnant. There is bombing, war, hunger, deprivation, bad. It is a pity that Hitler had not learned, illiterate loser. He tried to fight gays, and because of his actions of gays in Germany became more.
In fact, some behavioral traits that we used to take brand social may in part be related to our biological nature. Indirectly it proves the monkeys. You know that if you give the monkeys toys, boy monkeys prefer to play with toy cars and carried with them two times more time than with other toys. About girls monkey in 2010 was published an amazing study that girl chimps in the wild play with dolls.
That is, chimpanzees living in the forest, she finds a piece of wood, and this piece of wood goes, calms her, eats with her, sleeps with her and, importantly, never use this wood for any utilitarian purposes. That is, do chimps use tools, they use, for example, with chopsticks, in order to smash something, some kind of nut shell or something to extract, for example — termites. As for this wand, it is only for love and care, and any things not do it. As soon as a young female starting her first cub, she throws these games. One time I saw adult chimpanzees, who cradled a doll, but it turned out that it was a childless adult chimpanzees.
It seems that society is unlikely to somehow affect whether or not we're men or women, because it is innate and depends on the brain, how it formed, what kind of hormones. But the society obviously can affect what we put in it, what forms of behavior seem normal for a man what forms of behavior seem normal to women, and which seem to be abnormal. In this case, one can cite the example of female programmers, because the first ever computer programmer was a woman: in the nineteenth century, Ada Lovelace came up with a program for a hypothetical computing machine. There were many other wonderful women programmers. For example, the Apollo program was headed by Margaret Hamilton, which has created a very good software devices that landed on the moon.
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However, approximately 70 years at American universities have increased the number of women who received degrees in various Sciences, a growing number of women physicians, increasing the number of women lawyers, a growing number of women-physicists, and an increasing number of women who received a bachelor's degree in computer science, computer science. But then in the mid 80s something happened. Women doctors, lawyers, and physicists continued to become more and the number of women studying programming, came down. And that's according to the U.S. Department of education in 1983, among all bachelors in computer science was 37% of girls, and in 1998 26%. The fall is quite strong. What is the reason, not fully understood, but the most realistic version is that in the mid-80s, began to appear on personal computers. And, according to all opinion polls, it turned out that the computers bought for the sons and not daughters, because, well, why the girl computer, she plays with dolls, and the boy let sitting at the computer. The result was that when the girl decided to go study computer science, it turned out that she knows much less than her peers-boys, because all they had computers.
Who is smarter: man or woman?Who is smarter: man or woman? Correct answer: don't know. If we directly compare IQ or any other form of measurement of intelligence g-factor, the standard factor of intelligence, in different studies obtained different results, but always they do not greatly differ. That is, either it turns out that in General there is no difference between men and women, or that the difference in favor of men, but which is not a very significant one, three, five paragraphs. Again it is clear that this occurs when we averaged a large sample, and says absolutely nothing about the intelligence of any particular person. There is an interesting evidence that people think in different parts of the brain: IQ in males correlates with the amount of gray matter in the frontal and parietal lobes, and women with the amount of gray matter (i.e., bodies of neurons) is also in the frontal lobes, but besides this and in Broca's area. That is, perhaps, the intelligence of women a little more "verbal", because Broca's area is associated with speech.
There are good studies, for example, studied 72000 high school students and how they passed different tests on reading, math, vocabulary, science literacy and more. The results showed that in General, the results of boys and girls are comparable, but boys have more individual variation, that is, girls are getting closer to the Golden middle, all roughly get four, some have five, some three, but the average is four. And among boys more as the most intelligent and the most stupid. That is, among boys more than those who receives 5+ than among girls, and among boys more than those who receive a unit than it is among girls. That is, many parameters associated with intelligence, women have a more narrow Gaussian. Perhaps it is the point when you say: "why geniuses among the solid men?". You can also say: "among morons, too solid man."
Here, of course, also very important to understand the extent to which it is connected with the pressure medium. I know one large study published in the journal Science, which looked at more than two hundred thousand people the school's performance in relation to the floor. They found that the mathematical ability of boys better verbal ability than boys. And verbal ability of girls is better than the mathematical ability of girls. If we compare between the sexes, it turns out that girls in any country are ahead of boys when it comes to reading. As for mathematics, it is usually the boys are ahead of girls.
But then scientists did this kind of thing: they compared it with the social indicator of women's emancipation. They looked different, how they expressed the emancipation of women, as the woman easily to access education, jobs, power and so on. They found that there is a correlation. If a country has a low level of women's emancipation in this country, the boys know math much better than girls. But if the country has a high level of women's emancipation, in this country girls know math as good as boys, or even ahead of... posted