My personal understanding of human nature is that it's capable of the whole range of attitudes, from violent selfishness to pure altruism. I think the society

My personal understanding of human nature is that it's capable of the whole range of attitudes, from violent selfishness to pure altruism. I think the society you live in and the way you're brought up matter a lot in moderating these attitudes. If you're taught that you should be selfish, that it's a dog-eat-dog world out there etc. then of course you'll lean towards selfishness and transactionalism. This however is not a direct aspect of human nature, just a consequence of nurture.