p. 92.

"An adult by contrast, generates his or her own intellectual challenges. The 'environment' is not some real inflexible thing: it is a unique set of influences actively chosen by the actor himself or herself."

"Having a certain set of genes predisposes a person to experience a certain environment....The genes are agents of nurture....Nature can act only via nurture. It can act only by nudging people to seek out the environmental influences that will satisfy their appetites."

p. 92-93

Matt Ridley, The Agile Gene: How Nature Turns on Nurture, (New York: Harper Collins Press, 2003).