David Rakoff

Innate mechanisms endow the visual system with highly specific connections, but visual experience early in life is necessary for their maintenance and full development. Deprivation experiments demonstrate that neural connections can be modulated by environmental influences during a critical period of postnatal development.

I don't deny the importance of genetics. However, the fact that I might be altruistic isn't because I have a gene for altruism; the fact that I do something for my children at some cost to myself comes from a history that has operated on me.