Some people lack the brain development to understand empathy. See, it takes an advanced mind to project themselves in someone else's shoes, you have to throw away the superficial world and look at things in an abstract manner. Only humans have this ability, animals don't. That is how we are able to imagine a world the way it's supposed to be, rather than what it is. In a perfect world, cold hearted individuals won't take advantage of naive children. In the animal world it's every man for themselves. Yes, monkeys have displayed the ability to play video games.