Hey there. While you're waiting for a reply to your post, we thought we'd give your thread a timely bump.
But don't twiddle your thumbs in the meantime! Kick off your revision and study time by heading to our Learn Together section.
In Learn Together, you'll find interactive study tools to help make your revision quicker and easier. We've also got thousands of handpicked assignments analysed by great teachers, so you can learn from top-marked work. And there's tons more too: get started on Learn Together now!
This is all off the top of my head so can't remember the exact details but figured I'd try to help since no one has commented yet
There are lots of studies about how brain structure can be linked to violent behaviour. Most famous example is probably Phineas Gage who's behaviour was changed after a brain injury, didn't kill anyone but it can be linked in. I've read about a man who shot loads of people before the police shot him while trying to stop him, he had previously donated his brain to science because he felt like his behaviour was changing and when they dissected it there was a brain tumour. There was a study where cats had part of their brain lesioned and after would continuously fight with each other.
There's also studies suggesting a genetic link. I'd bet there have been twin studies done on it. I definitely remember a study of criminals (I think violent) who had either been adopted or had an absent father and it turned out a significant percentage of their fathers had been in prison.
I think hormonal factors could also be responsible. Like the production of serotonin or dopamine as these have a calming effect.
Sorry that its all quite vague but hopefully it gives you an idea of what to search for and read up on. Will come back if I remember any names