The Agile Gene: How Nature Turns on Nature. Acclaimed science writer Matt Ridley turns his attention to the nature-versus-nurture debate in a thoughtful book about the roots of human behavior. With the decoding of the human genome, we now know that genes not only predetermine the broad structure of the brain, they also absorb formative experiences, react to social cues, and even run memory. They are consequences as well as causes of the will. Trade paperback.