Main differences between men's and women's brains

The brain is a very complex organ, since it monopolizes (in something less than 1500 grams of tissue) everything we feel and think, what we want and believe about the world around us and ourselves. That is why it has always generated an enormous fascination, and that we know it a little better every day.

Traditionally, men and women have been assigned different ways of acting and feeling, which, although they may respond to discrepancies in social conditioning, have been the stimulus to explore possible dimorphisms in the structure and function of their brains.

The research that has been carried out over the years has not been without controversy, since it is nourished by confusing and contradictory findings. So much so, that even today it is difficult to assume that any of them may be the subject of global consensus; or considered as a substantial explanatory factor for the cognitive-affective, attitudinal and behavioral differences between the sexes.

However, in this article we will explore the results that certain evidences enjoy in this field of scientific knowledge, without forgetting that each one of them continues to be studied for a future adjustment of their plausibility and scope. Let us delve, then, into the differences between the brain of men and that of women through this summary of the most important findings.

Differences between men's and women's brains

When comparing the brain of both sexes, one of the details that is obvious is that that of men is significantly larger and heavier than that of women. On average their volume is 1260 cubic cm, while theirs reaches about 1130. It is estimated that the male brain is 10% larger, and that it has a weight between 10% -12% higher. This fact is due to the fact that the body size of the one and the other is also different, to the point that controlling this variable becomes a proportional comparison of the absolute difference between brains (which is not linked to intelligence or any other function cognitive).

If we observe the gray matter and white matter in subjects of both sexes (total number of nerve cells and synaptic connections respectively) it becomes visible that the male has up to 6.5% more neurons and that the female has 10% more than "networks" (as well as superior neural compaction in certain areas). This data indicates a notable dimorphism attributable to sex, of greater clarity in specific regions of the brain parenchyma (as will be detailed in subsequent chapters).

An interesting nuance is that the "adjustment" of the two brains according to body weight precipitates an inversion of this effect, in such a way that men would harbor more synaptic connections and women more concentration and number of neurons. Recent studies in this regard begin to question the fact (traditionally accepted) that either sex has a greater amount of such cells or their connections, making it an uncorroborated figure.

The naked observation of the brain shows a corpus callosum of greater density among women. Such a structure is composed of a bundle of nerve fibers that has the function of uniting the hemispheres, facilitating interaction and mutual collaboration. This area, located deep within the organ, is essential in multiple daily tasks for which "integrated" information processing would be required.

Therefore, it has been established as a finding by which to support a supposed greater laterality in the male (understood as the control of each half of the body by the opposite side of the brain and the specialization of the hemispheres), despite being a fact that does not enjoy complete agreement. There are also works that associate the same connectivity with a greater ability to contact emotions and with a certain susceptibility to depression (more common in women).

Observing precisely both hemispheres, there are slight differences in the left (larger in men) and the right (which is equated with its opposite in the case of women), which has offered empirical support to the traditional idea of ​​dissonances between the sexes in dimensions such as language or spatial processing.

Precisely in relation to verbal ability, a difference has been found for the volume and size of the planum temporale (11% larger in women), a structure posterior to the auditory cortex involved in the neurological development of relative cognitive functions to the use and learning of a language. The greater asymmetry in the male accounts for his tendency towards hemispheric specialization, in contrast to the "holism" characteristic of women (more distributed cognitive functions).

As for the convolutions and fissures (the folds that the brain shows on the outside) it has been found that the anterior commissure is 12% more extensive in women. It is believed that it serves to connect the temporal lobes of the hemispheres through the midline, facilitating their interaction in those people who were born without a corpus callosum (agenesis). Likewise, we know that postcentral gyrus is 10% more pronounced among women, which would be associated with central vibration processing and fine nature motor functions.

Regarding the cerebral lobes, there is evidence on the accentuated presence of neurons in the male temporal neocortex, although the data is reversed in the posterior region, where women have a greater number of neurons on average (recognition of spoken language and face perception). On the other hand, the lower parietal lobe is thicker in men (especially in the left hemisphere), and is related to skills of a spatial / mathematical order (connection between parts of an object, three-dimensional rotation, perception of speed and tempo or distance estimation).

Finally, some structures of the frontal lobe, such as the orbitofrontal cortex or others, are thicker among women (involved in the development of higher cognitive functions and in the central inhibition of impulsive acts).

Specific structures and function

From now on we will see which are the specific regions for which some differences between men and women are recognized. These are generally subtle divergences, which are estimated on average, without considering that the neuroplastic processes of the human being are subject to his experience and to the circumstances of the environment in which he develops his day to day. That is why each individual brain can be very different from the organic sex standard to which it belongs, and that much of what is described here could be due to cultural or educational causes.


On the other hand, there are hypotheses that attribute testosterone a fundamental role for intersex divergence at the cerebral level, so it would be a key influence to structure the organ (which would begin in gestation). It is understood, therefore, that the findings to be described imply a clear confluence of the biological and the social; Although the way in which both contribute to the equation is not yet fully known. We proceed to delve deeper into the differences between the male and female brains at the molecular level.

1. Hypothalamus

The hypothalamus is a brain structure whose function is essential for life; because it participates in a remarkable way in the regulation of processes such as temperature, hunger, thirst or circadian rhythms. It is closely coordinated with the pituitary to orchestrate all the metabolic regulation of the organism through multiple "axes" (gonadal, adrenal, thyroid, etc.).

Available evidence indicates that some of its regions, such as the interstitial nucleus, are larger in males. This is reproduced for the medial preoptic area, the brain area that is most closely associated with mating and reproduction. In these cases it is estimated that men double the gross volumes of women.

The hypothalamic suprachiasmatic nucleus (which regulates circadian and reproductive rhythms) reaches a similar size in the two sexes, despite the fact that it adopts different shapes for each case (rounded in men and oval in women). The latter is likely to connect differently with brain areas that are distant, which could explain certain differences attributable to sex, such as the greater sensitivity in women to the light variation that coincides with seasonal change.

2. Tonsil

The amygdala is a limbic region related to emotional memory and processing. Studies on such a structure indicate that males show a size up to 10% larger than that of females, and that it is also linked to different areas for each of the sexes (visual cortex / striatum in males and insula / hypothalamus in females).

Such findings indicate a greater emotional reactivity in men to environmental stimuli, and in women to aspects of their own corporality. Some research suggests that any morphological change in this structure occurs according to the levels of steroids in circulation.

On the other hand, it has been observed that when evoking emotional memories, men show intense activation of the right amygdala and women on the left. This nuance has been associated with differential processing of such information, in which males would emphasize generality and females would focus on details. Finally, it is known that the ratio of the proportional magnitudes of the amygdala and the orbitofrontal cortex is higher in women, which makes it possible for women to control impulses more efficiently (as well as plan and use emotion-oriented coping strategies).

3. Hippocampus

The hippocampus is an essential structure for the consolidation of memory in the long-term store (generating a new memory) as well as for the interaction between emotions and perceptions. Original studies on this issue indicated that women had a greater volume of cells in these bilateral structures, which would explain why they could integrate declarative memories with affective life more efficiently (adding emotional nuances to what was lived). However, recent studies (in which the global size of the brain has been controlled) do not show differences between the sexes, making the conclusion currently more acceptable to the scientific community.

Difference in spatial orientation between the sexes (emphasis on details such as spatial "markers" in females or articulation of schematic mapping in males) have been classically associated with discrepancies in this structure, although the parietal lobe would also contribute in some way. . There is much evidence that training in spatial vision has extensive resonances on hippocampal neurons, thereby increasing the volume of these regions.

4. Cerebellum

The cerebellum is an essential structure for maintaining posture, balance and level of consciousness. The research carried out to compare the sexes projects disparate information, but almost always points to a higher volume in the case of men (approximately 0.9%).

This phenomenon is associated with superior motor control in the case of men, and more specifically for what is usually known as gross motor skills (playing group sports or running, to which their more developed muscle mass also contributes). It would facilitate a tight "perception" of the body's own position in space.

5. Ventricles

Our brains have four large empty / interconnected spaces inside them, called ventricles. The cerebrospinal fluid circulates through them, allowing proper hydration and nutrition of the nervous tissues, as well as their protection in the event of impacts. Such vaults tend to be of a higher volume in males, which is consistent considering the fact that their brains (in general) are too. These structures can see their size increase in some psychopathologies (such as schizophrenias or type I or II bipolar disorder), which is associated with greater cognitive decline.

Other data to take into account

As previously indicated, the male brain has more asymmetries than that of the female, which means that its two hemispheres show more marked differences between one and the other than in the case of the latter. Beyond this, very recent research suggests that men are also more different from each other (in terms of organ structure) than women, which means that there is greater variability among them. This fact could correspond to the organizing contribution of prenatal steroids, which elicit differentiation in such a phase of development (masculinizing a brain that is initially feminine for everyone).

What we know about the brain helps us understand why there are differences between men and women on issues like emotional processing, spatial vision, or language. However, it is essential to keep in mind that every individual has the power to shape their brain through experience and habit, regardless of whether they are a man or a woman.