I think that Obligation is a learned trait, my parents taught me that when I get older I would have obligations and that I needed to meet them, one obligation is hold down a full-time, learn how to budget, and support a family. These are obligations things that you need to do.
I agree that it is something that is learned. There are things that some people consider to be obligations and others do not. In my household, I learned that it is my obligation to the rest of the household to do my part of the chores. Other people may not feel that way, so therefore, it would not be an obligation.