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Nature vs Nurture

Anthony G Benoit

On June 26th, 2002, with British Prime Minister Tony Blair by his side, President Clinton announced that the human genome had been sequenced by a public consortium, the Human Genome Project, and a private company, Celera Genomics. In February 2001, the American journal Science and the British journal Nature published drafts of the genome. While some were amazed that the human organism could be described by a mere 30,000 genes (only twice as many as in a fruit fly), others saw that publication as heralding a new age in the treatment of illness and foretelling the solution to a riddle that has plagued intro psych students for generations: Is human behavior and character caused by in-born factors or environmental influences?

Richard Fulkerson calls our attention to a line from the 17th century, "Nature makes the boy toward, nurture sees him forward" (Richard Mulcaster) and from Shakespeare, "A devil, a born devil, on whose nature / Nurture can never stick" (The Tempest). But it was Galton (Darwin's cousin) who called this question the "nature vs nurture" debate.

For example, what causes:

Studies of these and other characteristics typically reveal no simple cause, even for things that run in families.

Over the last century or so, different scholars have emphasized different causes of behavior.

What are we contrasting?

Genetic information vs developmental process

Instinct vs learning

History vs environment




Developmental pathways

Prenatal nutrition


Peer pressure

Parental role models




Does it make more sense to contrast sources of variability?


Family environment

Role within family

Peer group

Larger culture

In an article titled, "Three laws of behavioral genetics and what they mean," Eric Turkheimer summarized empirical findings on why people are different from each other with these three laws:

  1. All human behavioral traits are heritable.
  2. The effect of being raised in the same family is smaller than the effect of genes.
  3. A substantial portion of the variation in complex human behavioral traits is not accounted for by the effects of genes or families.

Why ask?

Often missed in the debate is that uniformity or individuality tells us little in itself about the origin of a trait.

What do genes do?




Nature? Nurture? Yes!

Influence of Life Stress on Depression: Moderation by a Polymorphism in the 5-HTT Gene (Caspi, et al., 2003, Science 301:386-389)

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Anthony G Benoit
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