Sunday, 18 September 2011

Child development, Nature vs. Nurture

Some scientists think that people behave as they do according to genetic predispositions. This is known as the "nature" theory of human behavior. Other scientists believe that people think and behave in certain ways because they are taught to do so. This is known as the "nurture" theory of human behavior.

In the most widely publicized study of this type, launched in 1979, University of Minnesota psychologist Thomas Bouchard and his colleagues have chronicled the fates of about 60 pairs of identical twins raised separately. Some of the pairs had scarcely met before Bouchard contacted them, and yet the behaviors and personalities and social attitudes they displayed in lengthy batteries of tests were often remarkably alike.

The first pair Bouchard met, James Arthur Springer and James Edward Lewis, had just been reunited at age 39 after being given up by their mother and separately adopted as 1-month-olds. 
Springer and Lewis, both Ohioans, 

  • They had each married and divorced a woman named Linda and remarried a Betty. 
  • They shared interests in mechanical drawing and carpentry; 
  • Their favorite school subject had been math, 
  • Their least favorite, spelling. 
  • They smoked and drank the same amount 
  • They got headaches at the same time of day

The Nature Theory - Heredity

Scientists have known for years that traits such as eye color and hair color are determined by specific genes encoded in each human cell. The Nature Theory takes things a step further to say that more abstract traits such as intelligence, personality, aggression, and sexual orientation are also encoded in an individual's DNA.The search for "behavioral" genes is the source of constant debate. Many fear that genetic arguments might be used to excuse criminal acts or justify divorce.

If genetics didn't play a part, then fraternal twins, reared under the same conditions, would be alike, regardless of differences in their genes. But, while studies show they do more closely resemble each other than do non-twin brothers and sisters, they also show these same striking similarities when reared apart - as in similar studies done with identical twins.

The Nurture Theory - Environment

Supporters of the nurture theory believe they ultimately don't matter - that our behavioral aspects originate only from the environmental factors of our upbringing. Studies on infant and child temperament have revealed the most crucial evidence for nurture theories.

American psychologist John Watson, best known for his controversial experiments with a young orphan named Albert, demonstrated that the acquisition of a phobia could be explained by classical conditioning. A strong proponent of environmental learning, he said: 
"Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I'll guarantee to take any one at random and train him to become any type of specialist I might select...regardless of his talents, penchants, tendencies, abilities, vocations and race of his ancestors."

If environment didn't play a part in determining an individual's traits and behaviors, then identical twins should, theoretically, be exactly the same in all respects, even if reared apart. But a number of studies show that they are never exactly alike, even though they are remarkably similar in most respects.
So, was the way we behave engrained in us before we were born? Or has it developed over time in response to our experiences? Researchers on all sides of the nature vs nurture debate agree that the link between a gene and a behavior is not the same as cause and effect. While a gene may increase the likelihood that you'll behave in a particular way, it does not make people do things. Which means that we still get to choose who we'll be when we grow up.


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