Darwinism suggests "Survival of the Fittest", you could suggest a sub-conscious primordial erge to survive is what makes people seem selfish with their own plans dominating their own paths.
However thats understandible afterall, most would prefer to see themselves having "Free will" to make their own decisions rather than being enforced into servitude of others. Although you could suggest for true survivalism of the species "co-operation" is more important since we as a species are stronger in numbers than individuals. This doesn't just apply to the first instance of men dealing with a predator like a Saber-tooth tiger, but also dealing with the puzzles that people concern themselves with like Philosophies and Science.
However this is all a suggestion of why Intellect should suggest that co-operation is the best form of strategy for survival for both a species as a whole and as an individual, since the only other reason is that of Empathy.
Empathy is a tricky thing, since it's dependent on how a person has been brought up and how their values have been shaped. To some empathy is a stranger which is why their lifes can be twisted into torture or anger and therefore they might commit crimes or atrocities for not seeing they have done wrong.
To others that wrong and injustice is all to blatently seen because their moral understanding and parental benefactors might have been far fairer. I might have suggested that some forms of religion have also shaped some peoples formation of empathy and understanding, however Religion is not necessarily right. Some things that people do in the sake of their religion is wrong fundementally (this is proven with the current jihads, the Spanish Inquisition, numerous wars and genecidal activites [The Crusades], People being classed as a heretic etc).
So you would be correct in suggesting that some people fall victim to "Programming", as they are no longer making their own moral judgements based upon the viewage of the whole but allowing others to define their ethics based upon doctorines in such things as Religion. (Of course it's not just religion, peer pressure and the need for an individual to fit into what they see as being their grouping within society can also generate such doctorines, for instance an occurance of racism to fit in with supposed friends when the individual a person is being racist to is doing nothing more wrong than just being born of a different ethnic backgrounding).
