<p>It really depends what culture and country you’re from. Political ideologies play a big part as well as ideas of ‘social responsibility’. Study some Marx, read some disturbing texts by Hayek (this is a smokescreen, note the endorsement by the Ford corporation) read some Nietche about ‘equality and ideas of civilization about the top and the bottom of society’ and some Durkheim about the ‘rules of sociological method’. Read some theory on ‘Kensian economics’. The reason people are selfish/not selfish is based on what they think is morally ‘right and justified’ for all (so you’re going to have people from different countries entrenched in a particular ideology). This is a start, game theory is also good but save that for later. Have a look at the ‘Wealth of Nations’ by Adam Smith who came up with the concept that ‘greed is good’ but most conservatives/republicans hide the fact that Smith retracted a lot of what he said at the beginning towards the end of his book after seeing his theory demonstrated by the slave trade in Jaimaca. This book was the founder of capitalism: however there is some moral lessons to be had in ‘free enterprise’ there are some obvious pitfalls in being ‘selfish’.</p>