From Informed Comment:

...

A century of careful medical and psychiatric studies tell us that the juxtaposition of absolute weakness and absolute power provokes violence. The bound and hooded Iraqi prisoners lying naked on the floor of Abu Ghraib prison invited attack.

So shocking is such a statement that few of us have wanted even to consider it. To deal with its implications requires us to reexamine our very concept of our humanity. So to get around that inhibition, some scientists, like the Nobel Prize winner Konrad Lorenz, posed “our” problem to animals. What he found was that those animals that have “weapons systems,” like the lion with its claws and fangs, have evolved to practice restraints. Had they not done so, their species might not have survived. So the winner in a fight among lions will make ferocious noises but will usually stop short of killing the lion he has just knocked down. In contrast, those creatures, like that symbol of peace, the dove, that do not have lethal weapons have not evolved to practice restraint. They did not need to. Lorenz observed a dove actually torturing another to death.

...

More.