Violence can quite often make sense as a way to achieve something, and it's possible to understand why in certain circumstances a capacity for violence has survival value.

What is harder to understand is where cruelty fits in, especially the kind of cruelty that doesn't seem to obtain any advantage, over and above whatever satisfaction is felt by the person.

For example, I was just reading a really vicious and nasty post on another thread directed at a young person who had done nothing whatsoever to deserve it, other than write an essay that someone else had posted on another website. And that set me thinking about other examples of similar gratuitous nastiness, some types of vandalism, for example.

Where is the survival value that can explain the capacity and appetite for that kind of thing?