Every species of animal in groups has the ability to be sensitive to the pain or suffering of its peers. Solidarity is part of their genetic code because in most cases it is a guarantee for the survival of the species. Why is it, then, that some people are basically insensitive to the suffering of others? How do they close themselves off emotionally to everything external to them? What makes someone become insensitive?
There are various possible answers to these questions. The causes that lie behind insensitivity range from the existence of serious pathologies to a state of extreme vulnerability. The paths to becoming insensitive are also many, and they include many different manifestations.