Nature vs nurture’s impact on our lives

By Natasha Josefowitz, Ph.D.

Natasha Josefowitz

LA JOLLA, California — A kindergarten—two little girls: one is sitting quietly by her teacher, not really wanting to engage in the other children’s activities. She is shy. The other little girl can hardly be contained. She has to be caught running out the door and totters dangerously on the highest rungs of the playground bars. She is always ready for the next thing.

The shy girl will probably stay risk-averse as she grows up, preferring the security of the status quo. She will dress conservatively and follow a traditional way of life. She prefers predictability and the tried and true. Change is threatening, and she will fight against it. She will be a churchgoer and a member of conservative politics. She will most likely be a Republican.

The other girl will be harder to raise, getting into trouble, always trying new things. She may be at the head of her class or at the bottom, depending on what interests are pulling at her at the moment. She will probably have several boyfriends and get involved in a series of causes, most of them with a social consciousness. She will want to live independently and go into unknown territories—whether travels or research—championing avant-garde positions. She will vote for choice, gay marriage, and gun control. She will probably be a Democrat.

Of course, I have exaggerated these two positions. Most people do not fall into these extremes, but can stay close to them; some fall in the middle—the independents.

However, my point is that we are genetically predisposed to prefer certain lifestyles, moral positions, ethical stances, even spouse and career choices, and the way we raise our children. Some find a certain comfort in security and a discomfort with anything that threatens this. Others chafe at the bit and need adventure and stimulation to feel alive, with little patience for “things as they are.” Although I lean more towards the second category, it is imperative to understand that both are needed for the survival of our society and nation. We need a secure basis from which to fly.

Although we tend to perceive the world as either friendly or hostilethat is not the whole story. Epigenetics enters the picture. Epigenetics is the way the environment impacts and regulates gene activity. For instance, if a child has experienced parental abuse, he or she will be hyper-vigilant to threat cues, will have a bias to attribute hostile intent from others, will have an increased heart rate, frequent release of testosterone, and react with anger as a self-defense against anxiety. These children will often be the school bullies.

On the opposite end, nurturing parents will raise children that will be less reactive to stress. Since social factors impact the brain, is there a critical period where negative influences can be reversed? According to Dr. Eric Kendell (Charlie Rose’s KPBS-TV segment on the brain), the window closes at the age of two, but sometimes it is still possible to negate these influences until age five.

An example of the environment changing the structure of the brain is seen in a cab driver who has an enlarged hippocampus. This is due to the amount of information needed to do the job, such as remembering street addresses and city sitesWhen these cab drivers quit, their hippocampuses shrink back to their original size.

We start with nature which can then be influenced by nurture. Both genetics and environmental exposure will profoundly affect the two little girls and their overall perspective and personalities throughout life. Our genes will influence our behavior and how our environment can modify them.

It is important for all of us to understand where we came from and the impact of the environment on our daily lives in order to recognize our own tendencies and understand our needs.
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© Natasha Josefowitz. This article appeared initially in the La Jolla Village News. You may comment to [email protected]

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