The most read LJ bloggers and authoritative columnists in the weekly SUNMAG column.
Maria Anikanova, neurologist, top LJ blogger
It all starts at birth. In boys, in the first week of life, the concentration of the male sex hormone testosterone in the blood suddenly increases. Its high values persist for two weeks and then gradually decrease. In girls, estrogens increase from about the second week of life and last for about a month.
Nature manages the resources of the organism very rationally. So what is this hormonal fireworks display in babies for, reminiscent of a mini rehearsal of puberty? Neurophysiologists believe that this is necessary to "program" the sex differences in the brain.
The surprising does not end there: studies show that receptors for estrogen, progesterone and testosterone in humans are not only in the genitals and hypothalamus - the hormonal "conductor" of the brain, but also in other brain structures that are responsible for memory, emotions, planning. This suggests that the brain should function differently in men and women. Moreover, nerve cells are not only susceptible to the action of male and female sex hormones, but they themselves are able to form them!
And this fact becomes the reason for a lot of speculation about the difference in the intellectual abilities of men and women. Inquisitive supporters of patriarchal values quickly find information that a woman's brain is, on average, smaller in volume than a man's. Moreover, the ladies usually have less gray matter - it turns out, and the cat cried nerve cells in their brains too! Isn't it proof that men are naturally smarter, smarter and smarter than women?
However, the fact of a larger brain volume is rather a manipulation from the field of eugenics. It cannot be called a weighty argument. They will not be able to operate in the scientific community - they will be laughed at. An increase in brain volume and mass does not at all promise a rapid increase in intelligence and the emergence of new skills and abilities. The large brain may not be very functional. It just naturally belongs to a large individual.
The rationality of the brain depends not on the size, but on the organization of neurons and on how often the owner uses it to solve various problems, gain new experience and memorize information. Therefore, gender does not determine the development of the brain and the level of intelligence. Everything is decided by the environment and how effectively a person learns to interact with it.
Sex hormones and the brain
It is believed that normal levels of the female sex hormone estrogen help maintain a reasonably high level of intelligence. Of course, if estrogen is higher than normal values, it will not make you Sofia Kovalevskaya. However, the age-related decline in estrogen levels in women is considered by some researchers to be a predisposing factor in the onset of Alzheimer's disease and other neurodegenerative ailments. There is another interesting effect of estrogens: the higher their level, the more difficult it is for a woman to orientate herself in the area and memorize abstract information. On the other hand, estrogens improve declarative memory, that is, the ability to remember events, the location of objects, and notice different details.
Studies show that women, on average, are less likely to remember new routes and make more mistakes when trying to retrace a new path. Men have poorer verbal memory. It is more difficult for them to memorize names, dates, and also to replenish their vocabulary with new words. One might assume that such a difference is associated with differences in the upbringing of children of different sexes, because it is customary for guys to encourage exploratory interest, courage and curiosity, and in girls - perseverance and diligence. However, studies in other mammals show a similar picture. So, the reason for the differences here still lies in the effect of sex hormones on the brain.
Progesterone is able to alter synaptic transmission between nerve cells. In other words, it can make the communication of neurons closer, speed up the exchange of information, and make its assimilation more productive. Experiments in rats have shown that raising estrogen and progesterone levels can improve the function of the hippocampus, the brain structure responsible for memory. In addition, progesterone helps restore myelin fibers. This is probably related to the improvement in well-being in patients with multiple sclerosis during pregnancy. Very often they go into long-term remission. Unfortunately, after childbirth, a sharp deterioration often occurs, and the disease again begins to destroy the nervous system.
ogens, male sex hormones, also influence brain development. It is assumed that they are responsible for the lateralization of brain functions, that is, for the specialization and deepening of its functions. This makes the man's brain “single-tasked”. In women, the interaction of the hemispheres is more complete, so they are "multitasking", able to quickly switch and sometimes even do several things at once. The idea of lateralization of brain function should not be taken too seriously: it was based on the fact that damage to Broca's zone (the area that is responsible for speech) in men causes much more catastrophic consequences than in women. However, modern data show that everything is not so unambiguous and depends to a greater extent on age, intelligence and the extent of the lesion.
Whose Brain Is Better?
There are many publications on the effect of sex hormones on brain development. There is no doubt that the brains of men and women are really different - not only because of the different density of neurons in the speech centers (women have more gray matter there, therefore, verbal memory is usually better developed), lateralization of functions and other complex neurophysiological things.
Do not forget that the environment has a much greater impact on the development of the brain and personality than all neurophysiological reasons combined (when it comes to a healthy person). Girls are raised differently from boys. And expectations are also different: in some families it is generally accepted that if a girl doesn’t like mathematics and physics, then this is “simply not given by nature” and there is no need to strain, they say, the main task of a woman is to get married and have a baby anyway. And they will try to motivate the boy in the same family to study the exact sciences in all possible ways: they will promise a new smartphone for the passed exam, hire a tutor, buy books for self-study.
There are indeed differences in the workings of the brain between men and women, but this is not a reason to manipulate scientific data to prove that women are "by nature" stupid, ignorant, do not know how to control their emotions and have made much less scientific discoveries than men.
Unfortunately, you can still find publications in serious publications where authors allow themselves to draw sexist conclusions. Here is a quote from an article in the journal "Psychological Problems of Modern Education" from 2007 (authored by a woman): "The female form is responsible for preservation and the past, the male form is responsible for change and the future. This correlates with the position that women prefer and more successfully solve reproductive tasks (in which the requirements for innovation are minimal) with high requirements for the perfection of the solution, and men prefer and better solve the problems that are encountered for the first time (in which the requirements for innovation are maximum) with minimal requirements for the perfection of the solution. The high search activity also explains the greater number of original answers in the boys' works”. In other words, the author of the article unfoundedly declares that a woman was created to engage in everyday life and children, while men conquer the world, because this is how nature works, and besides, this is the order that everyone really likes.
On the abundance of such publications, the mythology of the male and female brain is being created. Such statements become the main (and, as a rule, the only) argument in online battles on the topic of gender equality.
The male brain is as beautiful in its structure as the female one. However, no brain is created exclusively for "solving reproductive problems." The clever organization of neurons and their numerous processes is needed solely for one purpose: to make the brain and its owner (or possessor) happy. Therefore, nerve cells store in themselves a huge potential for cognition, gaining new experience and using it for their own benefit. And what it will be: parenting, a scientific career, sports achievements, volunteering or creativity, or maybe all at once, is up to you. Regardless of the presence of the Y chromosome in the genotype.