Well, I am by no means a social scientist but I do have an opinion about this subject. Unfortunately it's an opinion that many have a tendency to disagree with but if you will allow me I will happily (egotistically) convey my thoughts to you. The most valuable human trait that can benefit society is self interest. I know that sounds contradictory and I know that it's hard for some to believe but it's true. Let me give you an example. Take a cobbler for instance ( that's a person that makes and sells shoes). When the cobbler sells a pair of shoes the customer is happy because he/she gets to show off a new pair of shoes, the customers family and friends are happy because they don't have to listen to that person complain about not having any new shoes, the cobbler's self interest kicks in and he becomes happy because he makes a profit that can help provide for his business all his employees and the welfare of his own family and his suppliers are happy because it helps keep product flowing which benefits their businesses, employees and their families and even the tax man is happy because he gets to collect a tax at several levels of the sale and income earning potential that supposedly goes to benefit the general welfare. Self interest creates scenarios that make everybody happy. So yes, I would have to say the answer to your question is self interest.