Neurons, in this early stage, are thrown together more or less at random and then left to their own devices. After birth, experience makes and breaks connections, pruning the thicket into precise circuitry. From the very beginning, what s in the genes is different from what s in the brain. And the gulf continues to widen as the brain matures. The genes still exert their influence some of the brain s circuitry is hard-wired from the start and immutable.
People don t have to learn to want food or sex.
This being a very popular topic in today s society, increases the likelihood that many people will be able to understand the concept. The writer uses everyday words and images in his explanation of some of the things the brain can do. What he says could be described and explained in very complex terminology, but he chooses not to do that. By using an easier and more common form of language, more people are able to understand what he is talking about. In this particular case, it is my speculation that common people or scientists could relate to the passage.