We've all experienced cruelty. Some of us may even admit to having been cruel. Most of us are lucky; we've only experienced cruelty's minor variants. They can be bad enough: workplace or school bullying, domestic abuse, the horrible, hurtful malice which seems intent on making other people suffer.
But cruelty can be much more extreme than this. Husbands can kill their wives; people can murder neighbours they've known for years; loving fathers can slaughter other people's children. (Note the choice of examples; most extreme physical cruelty is done by owners of a Y chromosome.) Such atrocities happen reliably in certain situations, and they happen so frequently -- and involve so many otherwise 'normal' people -- that we cannot explain them away as the result of mental illness. Those who are cruel, whether their cruelty is minor or extreme, are not to be excused so easily.
Why they do what they do is one of the most intractable mysteries in human existence. In recent years, however, some progress has been made. Although it's still very early days, exciting developments in the brain sciences have given us cause to hope that we may one day understand why cruelty occurs. In this blog I hope to look at some of those developments, and also to highlight some of the caveats involved in the scientific study of cruelty.