Our capacity to reshape or redevelop the human brain later in life is limited. The abilities to feel remorse, to be empathetic, to be sympathetic are all experience-based capabilities. If a child feels no emotional attachment to any human being, then one cannot expect any more remorse from him or her after killing a human than one would expect from someone who ran over a squirrel. They arise from children reflecting the world in which they have been raised. As any peace officer, prosecutor, or judge will tell you, they have looked into the eyes of such children.
Social science confirms medical science.
Of special interest is its report of the work of the National Institute of Justice, a part of the U.S. Department of Justice. A longitudinal study sponsored by the NIJ tracked one large sample group of abused and neglected children and one large control group of children who had not been abused or neglected. The study matched the groups for age, gender, race, and socio-economic status, so most of both groups were poor. The rates for both groups are high because the control group shared risk factors with the sample group such as poverty. Nevertheless, the sample group of abused and neglected children had significantly higher rates of arrest.