Self-less. To do something with absolutely no intent of "return" towards oneself.
Humans are pack animals, and often default to group oriented choices. It happens all the time, and the motive is not self reward. Empathy is not always the reason for action either; It can still be justified from a completely emotionless perspective. We can be quite utilitarian in nature, and sometimes the worth to others just outweighs the worth to self, so we act accordingly. No satisfaction or anything needs to come into it.