Paul Auster and Kaspar Hauser

In the first part of the New York Trilogy, Paul Auster mentions recorded cases of "wild children" - kids that have grown up without any interaction with human society. Kaspar Hauser is the famous case, but Auster mentions that there were at least two experiments where someone wanted to know what language a group of children would learn to speak if left on their own devices. This learning experiment was briefly mentioned by Jeannette Winterson in one of her books, too.

Anyway, it turns out that people who never learned anything about the human society or language in their childhood, can actually learn to speak, write, work, keep themselves clean and interact with other people. However, stunningly, they show no interest in sex or money. Well, that's something to think about for people who see the sexual behaviour of people as something natural.