Imagine I have a genetic script that compells me to paint my face blue whenever I see the moon. So if the moon appears, my face turns blue (due to my programmed behavior). If not, my face remains pink.
Imagine also that this script will run as described above ONLY if I carry gene variant X. (If I carry gene variant Y instead, the script will not run.)
So the logic looks like this:
The 4 possible outcomes of this genetic script are as follows:
- Blue face, because I have gene variant X, and I saw the moon
- Pink face, because I have gene variant X, but I didn't see the moon
- Pink face, because I have gene variant Y, and I saw the moon
- Pink face, because I have gene variant Y, and I didn't see the moon
You could say the color of my face is an equal product of both my environment (nurture) and my genes (nature), interacting.
But you would be wrong. Because the script, which anticipates various environments, is fully in my genes. The outcome is not affected by babies screaming or dogs barking. If a genetic script anticipates specific experiences, then the outcome is 100% nature, not nurture.
Here's another way to look at the same genetic script. President Andrew Jackson endured horrific experiences as a child, yet he was not traumatized by the experience. Assuming he was one of the rare individuals who LACKED the T gene variant, his genetic script resembled something like this:
We each possess the same genetic script. It's only the master switch (gene_variant_t) that is responsible for dramatic differences in outcomes in human traits and temperaments.