We all have different brains: the size, shape and way of functioning vary enormously from person to person. Is this variability innate or acquired? This question has long remained an enigma, but today, advances in neurobiology allow us to answer it at least partially. When a newborn baby is born, their brain has nearly 100 billion neurons. The stock will no longer increase, but the fabrication of the brain is far from over for all that: only 10% of the connections between neurons are formed.

Environmental stimulation

The rest of these neural circuits result from environmental stimuli, both “internal” (effect of hormones, food, contracted diseases) and “external” (learning, social interactions, cultural environment, etc.). It is the new brain imaging techniques that have led to such an assertion. By observing the brains of pianists over several years, we realized that the brain evolves according to their intensive practice. Thus, we observe in them a thickening of the regions specialized in the motor skills of the fingers as well as in hearing and vision.¹⁰. Likewise, a study has shown that the areas of the cortex that control the representation of space are more developed in taxi drivers, in proportion to the number of years of driving experience.¹¹. These studies show how the lived experience modifies and structures the functioning of the brain. This is called brain plasticity. This notion is fundamental because it shows the importance of the acquired knowledge of the innate in the differences in performance and behavior between the sexes.

Girls less good at math? Truly ?

The example of the supposed inferiority of women in science is glaring. Everyone has already heard this alleged truth to explain the absence of women in this environment. The president of Harvard University himself relayed this theory in 2005: “ The low representation of women in science subjects can be explained by their innate inability to succeed in these fields! So, innate or acquired? In 1990, a statistical survey¹²involving ten million students had established that boys performed better than girls in solving a mathematical puzzle. It is therefore concluded that women were genetically disadvantaged in the success of this so noble school subject. Yet 18 years later, the same study no longer found any difference between boys and girls. What happened ? Could the genome of girls have evolved in such a short time? Obviously, no. The 1990 research team undoubtedly overestimated the importance of genetics and forgot that humans are first and foremost the product of cultural and social history. A study¹³ dating from 2008 brilliantly managed to show the importance of these environmental factors. The researchers of this work noticed that the gap in performance in mathematics between the sexes was linked … to the female emancipation index! Thus, in Norway and Sweden, where the index is the highest, the performance gaps are the lowest. For Turkey, it is quite the opposite! The performance gap in math would therefore be a function of the egalitarian culture of the countries.

What about behaviors? Are they also conditioned by our society? Are women more emotional? Is it by “nature”?