How we inherit male and female behavior: a new idea about the environment and genes

Published on September 03, 2017

How we inherit male and female behavior: a new idea about the environment and genes

Original author: The Conversation
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Men and women

The infamous note from Google, written by engineer James Damor, has sparked years of debate about the differences between women and men.

Everyone, including Damore , recognizes the role of our social environment in shaping gender differences. Ideas about which jobs “fit” women, the pressure exerted on men who play “manly” roles — these feelings, expectations, and opportunities affect our gender role.

But it is generally believed that biological differences between the sexes create differences in behavior that even equal conditions cannot overcome.

In his note, Damore used scientific ideas, suggesting that the usual differences in interests between men and women (“things” and “people”) and preferences ( status and competition compared to family and cooperation) are partly due to evolutionary, biological differences.

If you stick to thisa widespread view, even the liberal environment of Silicon Valley cannot overcome such a deeply rooted opinion.

But what if thousands of years of upbringing reduced the need for genetic mechanisms to ensure gender differences? The idea that we propose in our new article .

Rich heritage

Evolutionary biologists recognize that offspring do not just inherit genes . It also inherits all kinds of resources : ecology, nest, parents and peers. And it seems that these persistent environmental factors can help ensure reliable reproduction of the trait in different generations.

Take, for example, the “instinctive” sexual preference of sheep and goats for partners of their species.

It is noteworthy that this adaptive behavioral trait, apparently, partially depends on early contact with animals of their own species. It was found that males of sheep and goats raised in a group of other species develop sexual attraction to them.

In this case, genetics is not the only inherited resource for development: a stable environment in which sheep grow with sheep is also important.

Rethinking Genetic Mechanisms

We suggest that an environment that teaches men to be men and women to women can make genetic mechanisms in some ways superfluous.

This helps explain what otherwise would seem very surprising: we can breed sheep who are attracted to goats in one generation. But perhaps this should not be so surprising. Only regular crossing of species will provide them with genetic insurance against their sexual preferences.

Genetically determined traits can be lost when some reliable environmental feature makes them unnecessary. One example is the loss in primates of their ability to synthesize vitamin C , since this vitamin is readily available in their fruit-based diet.

We do not claim that the examples we cite can be generalized to different types or behavioral traits: this is a matter of empirical research. But the understanding that stable environmental conditions can play a crucial role in the development and inheritance of adaptive behavioral traits is very important for people.

Human influence

The human environment includes extensive cultural, behavioral and environmental mechanisms for transmitting gender traits.

We highlight gender differences using names, clothes and hairstyles. We learn about them from the beliefs, opinions, behavior and demands of family, friends, celebrities, the media, art and science. People have an unprecedented ability to social learning , which means that most of us easily absorb these lessons.

A recent study in the Melissa Hines lab shows that gender can affect who we learn from.

The study showed that girls with congenital adrenal hyperplasia (VGN) exposed to unusually high levels of androgens (a group of steroid hormones including testosterone) show a reduced tendency to mimic the behavior of women and “obey” sex.

This may explain the greater interest of girls with VGN in “boy games,” an observation often used to support the fact that preferences in games for boys and girls diverge due to higher prenatal testosterone in boys.

Hines research shows the possibility that, to some extent, sex through testosterone affects who we learn from, but the environment determines what we learn. If the environment is gender, our preferences for toys will also be.

The brain is like a mosaic

At first glance, the idea that gender is not necessarily the only way to pass signs between generations seems incompatible with evidence. Studies show that the genetic and hormonal components of sex affect the structure and function of the brain.

However, recent studies in rats about the effect of sex on the brain show that these effects can vary and even be opposite in different environmental conditions, such as different levels of stress.

These interactions between gender and the environment, which can also be different in different parts of the brain, give rise to a brain made up of unique “mosaics” . Such mosaics have recently been discovered in humans .

In other words, gender affects the brain, but this does not mean that there are two different types of brain - “male brains” and “female brains”. Although you can predict a person’s gender with an accuracy higher than probability based on the mosaic of their brain, an attempt to reverse predict - predicting a unique mosaic of the human brain based on the shape of their genitals - would be more difficult.

Returning to gender disputes

The possibility that the main role of our genetics is to form sex from the culture around us supports organizational initiatives in favor of gender balance.

The downside is that the predominance of “gender” environments means that many aspects of the environment must change so that gender models can shift at the population level.

Those working to increase the number of women in technology and leadership have a lot to do. However, people are unique in their ability to transform the environment.

A century ago, our gender debate has focused on whether women need higher education.and voting. Today, such disputes are ridiculous due to the development of social relations and science. Now they are talking about technology and leadership.

As history has shown, when cultural ideas about what roles women and men perform “better” change, the actual roles of women change over generations .