How can we use the literature on feral children to explain the importance of interaction to human development? in what ways does this relate to the "nature versus nurture" debate?

The general conclusion from the books and stories and in very rare real life incidents on feral children and those brought up in confinement is that individuals don't wind up plainly human, or at least completely human, unless they can interface with other individuals, particularly at an early age. The idea of feral children connects with the central issue of the connection amongst "nature" and "nurture." The nature side argues that it is a built in nature of any human being to become the kind of person he is supposed to be while the Nurture side argues that it is the interaction, people teaching us and environment etc. which makes a personality. In the case of feral children the argument weighs more in “Nurture” side that nurture plays more role in determining the personality of a person than nature. 

depends on what they need