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(December 5, 2010)

The Female and Male Brains

As you know, men and women tend to think differently in a variety of important ways. What you may not know is these differences are more than cultural: they are — to a large extent — based on physical differences between the male and female brains.

As an example, when a 15-year-old girl gets together with her friends, she will spend most of her time talking, especially about her feelings and about other people. Thus, it comes as no surprise that this is exactly what teenage girls love to do (at a distance) using their phones. Boys as we all know, are different. Indeed, you could throw a brick into a large room filled with teenage boys and not have to worry about hitting anyone who spends even 10 minutes a day talking about his feelings with his friends.

Take even a cursory look in a place where teenagers gather and you will see that it is common for teenage girls to use their phones whenever they get a chance: talking with their friends, sending and receiving text messages, and sharing photos and videos. Girls also love to access social networking sites, the most popular such pastime being to check Facebook over and over and over.

To be sure, teenage boys also spend time on their phones and on their computers and, they too, like to talk, text, share, and check Facebook. They also like to play games and run apps (programs). However, it is far more common to see girls engaged in such behaviors, especially to the point of obsession. Teenage boys are much less interested in talking than they are in playing games and competing. When a boy becomes obsessive, it is much more likely that he will be playing a sport (such as Paintball), immersing himself in an elaborate, online multi-player role-playing game (such as World of Warcraft), or practicing music with his friends in hopes of emulating his favorite musicians. Thus, it only make sense that girls come to depend on their phones much quicker and more deeply than to do boys. (Conversely, many boys show a similar behavior towards video games.)

To understand why this should be the case, we well need to discuss the differences between the female and male teenage brains and consider what happens to the human nervous system during puberty: the great change that begins the long transition from childhood to adulthood. This we will do in the next section.

To prepare for that discussion, however, we must go back to the very earliest weeks of life and take a look at what happens to distinguish the female brain from the male brain in the womb.

As you would imagine, the details are complex and not completely understood. Here, however, is a basic summary that is good enough for our purposes.

The human nervous system starts to develop early in the life of the fetus; as it develops, it is sensitive to the influence of sex hormones. By 6 weeks of age, the male fetus starts to produce male sex hormones called "androgens", the most important being testosterone. Without testosterone, the fetus naturally develops a female nervous system. With testosterone, the fetus develops into a male nervous system.[1] In relative terms, this early dose of testosterone is a large one. In fact, its effects are just as important as the later, more obvious surge of testosterone that begins at puberty.

At about 8 weeks of age, the fetus' nervous system begins to develop, at which time it is exquisitely sensitive to the presence or absence of male hormones. If there is no testosterone, the fetus will develop a female nervous system. Under the influence of testosterone, the fetus will develop a male nervous system.[2]

Anatomically, the differences within the fetal brain are small. Nevertheless, they become significant later in life. In fact, certain areas of the child and adult brain will be larger or smaller, depending on whether or not testosterone was present during the earliest stage of life. Specifically, the female brain will develop more neurons and more connections in the parts of the brain responsible for verbal skills, emotion, and processing gut feelings. Within the male brain (under the influence of testosterone), these areas will be smaller and less developed. However, there will be significantly more growth in the areas of the brain responsible for sex and aggression.

The differentiation of male and female brains takes place in two main stages, both under the influence of sex hormones.

Throughout childhood, these anatomical differences do effect behavior. For example, girls tend to be more verbal than boys, and boys tend to be more competitive and aggressive than girls. It is during puberty, however, under the influences of sex hormones, that behavioral differences widen.

Thus, the differentiation of male and female brains takes place in two main stages, both under the influence of sex hormones.

First, at about the 8th week of gestation, the fetus' nervous system becomes either masculine or feminine, depending on the presence or absence of male hormones, a development has extremely important consequences later in life.

The second stage occurs during puberty. Under the influence of the large quantities of sex hormones produced by the testes (boys) or ovaries (girls), the child's nervous system goes through the a second powerful change, becoming even more masculine or feminine.

Thus, to truly understand girls and why so many of them have an extremely strong desire to have their own phones, we first need to answer the question: What happens to the female brain during puberty?

Before we do, however, I'd like to take a moment and introduce you to a 13-year-old girl who is obsessed with text messaging. Although her behavior is excessive, it will help us get a feeling for how teenage girls think about their personal phones.

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1. Introduction
2. A Word From Our Sponsor
3. The Female and Male Brains
4. Excessive Text Messaging
5. The Female Brain and Puberty
6. Introducing The Pleasure Center
7. Why Is It So Hard To Quit
8. Girls and Puberty
9. Girls and Premature Puberty
10. Why Your 10 Year Old Daughter Wants Her Own Phone
11. A Final Note
12. References