It's common with exciting breakthroughs in science that perception gets skewed and new facts lead to extreme interpretations. We seem to be in such a phase now with genes, which are being used to explain too many things in ways that are far too simple and mechanistic. I's one thing to say that a child gets her blond hair genetically, but quite another to say that a child who is chronically shy received that trait exclusively by inheritance.
Mechanists have staked out an extreme position, that all complex human behavior will one day be seen as genetically caused. At the opposite extreme, most psychologists have accepted for decades that behavior is created by early family influences, and especially by the style of parenting that a child is exposed to. (When you see a young child throwing a tantrum in the supermarket, do you automatically glare at the mother, or at the very least wonder why she doesn't make him stop?)
This is the old controversy between nature and nurture. No one should feel that genetics will finally settle the argument -- to believe that "biology is destiny" doesn't hold up to scrutiny. Your genes don't make you do things. They are involved in a complex entanglement of nature and nurture that makes each of us entirely unique. This point was brought home to me by an old article in Newsweek from 2000 that covered an extremely important and influential discovery in how our genes get triggered. Behavioral Genetics
Because this research has so many implications for every aspect of behavior, I will take several posts to discuss it. To begin with, researchers at McGill Univ. in Canada found that female rats aren't the same at parenting. Some take more time and care to lick their infant pups while others don't. As it happens, the pups that were almost obsessively licked and cared for grew up to be less stressed and more adventurous in temperament, while pups that were less cared for grew up to be stress sensitive, restless, and nervous.
Monkey researchers long ago showed that taking a baby away from its mother caused developmental problems of this kind. A widely circulated photo showed a baby monkey clinging to a wire-mesh surrogate of a mother monkey covered in soft padding. Even without a live mother, the infants were desperate for a simulacrum of being cared for. If deprived of any mother figure and placed in isolation, the babies showed disabilities that closely resembled autism and depression that persisted for life. This finding swung the pendulum toward the nurture camp, which insists that children must be given the proper environment if they are to grow up into psychologically healthy adults.
But the new research goes farther, because the rats' behavior has to come from the brain, and in order for the brain to trigger any behavior, genes have to fire. Genes aren't automatically triggered or "light up." They can express themselves a little or a lot or not at all. (The same holds true for cancer genes, which everyone possesses but which get triggered in unknown ways among patients who actually develop cancer.) In the case of the rats raised by good mothers, their brain genes expressed to a high degree for traits like self-confidence, sociability, and resistance to stress. The rats who were under-mothered have the same genes, but theirs didn't "light up." They remained unexpressed.
What this means is that both nature and nurture are involved. A gene may exist for specific behaviors (this is no longer in doubt), but outside influences still have a great deal to say. It's like being born with innate musical ability. You may possess the genes of a Mozart, but if you grow up on a desert island never hearing music, you won't turn into a musician. We need to adapt ourselves to this tempered view of genetic predisposition, because far too often people casually assume that genes are deterministic, the modern equivalent of the biblical " bad seed."
The Harvard psychologist Jerome Kagan did pioneering research forty years ago to show that babies are born with personalities. Every mother already knew this, but a segment of the field of psychology persisted in believing that a newborn baby is a blank slate, which means that parents got blamed when their baby was cranky, irritable, angry, shy, unsociable, or showed any number of negative traits. And parents believed the psychologists (one only has to think back to the so-called "refrigerator moms" who supposedly caused schizophrenia in their children due to aloof, cold parenting).
Now it is emerging that genes are the physical imprint of behavior, but to what degree they dictate behavior remains a mystery. How much can you blame your genes, or thank them? How much can you blame or thank your parents? It's a fascinating topic to dwell on.