There is always an argument about whether a particular psychological trait or symptom is genetic in origin or a product of environment. This is known as the “nature vs. nurture” debate. Most times the proper answer is “both.” For example, studies on twins have shown that there is a significant genetic contribution to depression. At the same time other studies have demonstrated that an increased susceptibility to depression occurs when certain events, such as the death of a parent, are experienced in childhood. Even height, which is a physical trait, is known to be influenced by seven or eight genes, and also influenced strongly by diet early in life. Certain conditions, such as migraine headaches, have a very complicated presentation, determined not only by a genetic vulnerability, but also diet, stress, and even sleep. It is interesting, but not often very helpful, to determine just how much of a particular trait is determined by genetics or by environment. After all, we can only influence the environment.
It is known that phobias tend to run in families. I have treated a grandmother, her daughter, and her granddaughter for fears that greatly resembled each other. It is said sometimes that phobias are influenced by a genetic vulnerability that is passed down from one generation to the other. One can always adduce and find some evidence for such a “genetic vulnerability.” The competing theory is that certain fears are learned, just as ideas in general are learned, during the process of growing up. Therefore, these fears run in families because they are taught. Just one example: parents can teach their children to be afraid of strangers and concerned about intruders. Other such fears include worries about germs, and ill health. And there are very many other fears that are termed phobias because they lead to avoidance.
Another possibility, which strikes me as likely, is that children are born clearly with different levels of reactivity. This can be seen directly after birth when physicians obtain an “Apgar score,” which is a general indication of health. Some kids move a little when the doctor claps her hands; other kids seem to bounce off the table. Surely this difference, which seems to reflect a level of reactivity that is constant throughout life, makes it more likely for the reactive kid to learn to overreact—or overlearn—those fearful ideas that a parent may express. Still, when I consider specific phobias, I am inclined to try to understand them simply in terms of what the phobic person has learned from his/her parents and not in terms of any basic vulnerability.
When I was in the army I was charged by my commanding officer with curing another soldier in the space of two weeks, “or else.” (In the army you can talk this way.) This soldier was afraid of going up in any building past the third floor. His father also was unable to go up into any building past the third floor. Obviously, there is no gene passed from father to son that prevents someone from going into a building up past the third floor. This was a learned fear, and it had to be unlearned. I spent about an hour a day going up with him in the hospital building one step at a time. It took about a week or so for his phobia to go away,
So, long experience inclines me to think that all phobias are learned phenomena. But a number of years ago my granddaughter did something that made me think twice.
She was about five months old and was being held in my daughter’s arms. We were in her mother’s room where a toy tarantula was tied to a grate that was fastened to a wall, which held other small furry animals also, all from my daughter’s childhood. My granddaughter took one look at the tarantula and shuddered. I didn’t see how that reaction could have been learned. My daughter was not afraid of spiders. Her husband, my son-in-law, was certainly not afraid of spiders. He had been a biology teacher and when my daughter met him, he had a Komodo Dragon living in his bathtub and a boa-constrictor in a cage in the living room. There were assorted other animals present, the only one of which I really remember was a frog that bit viciously at anything that walked by. This young man had certainly not taught his very young daughter to be afraid of spiders.
I think there is pretty good evidence that certain animals are born (I’m talking about instinct here) with an innate fear of spiders or snakes. I don’t see why in principle such a thing should not be true of human beings. Perhaps for the same reason, people develop a fear of thunder and lightning. It doesn’t really matter, though. In our clinic we routinely rid people of their fear of snakes, spiders, and other assorted animals, including birds, dogs and mice. (c) Fredric Neuman 2012
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