This is referred to as the nurture theory of human behaviour. A good example of a case to support this theory is the case of James H. Fallon. James Fallon is an expert on the minds of psychopaths and a neuroscientist who found out that he had the same brain pattern with a psychopath which led him to discover that he has the MAO-A gene (Warrior gene). The gene makes a protein that breaks down the messengers that control our thinking and behaviour. Also in a psychopath's brain, there is low activity levels in the brain region located towards its centre at the base of the temporal and frontal lobes This region is called the orbital cortex, and it is involved in regulating impulses and emotions. It also plays a role in aggression and morality. He (James Fallon) beliefs that even though he has the warrior gene and brain activity pattern of a psychopath, the fact that he grew up in a loving and nurturing environment has helped him to become a successful adult, possibly preventing him from developing into a full blown psychopath.
Another case that can be used to support the nurture theory is the case of the feral children (also known as wild children). Feral children are children These children tend to be confined by their parent or carers, live in the isolated in the wild or brought up by animals. The concept of feral children has existed before the time of the Roman. As legends would have it, Romulus and Remus who were the founders of the city of Rome would believed to be feral children who were brought up by a she-wolf and