“Most people think self-oriented and other-oriented motivations are oppositeness of a continuum. Yet, I’ve consistently found that they’re completely independent. You can have neither and you can have both.”
— Adam Grant
It’s a counterintuitive idea that you have to improve yourself in order to be able to help others. That means that at every given moment, as you work on something, your motivation is is both selfish and altruistic. But the fact (demonstrated by Adam Grant’s research, for example) that these motivations are independent is even more difficult to grasp.
In the end, I think that a selfish interest comes first. This is what sparks the initial interest in whatever we decide to do. Later on, as we develop some expertise in the subject, we might be able to maintain the interest as we find the purpose (as the answer to the “Why?” question starts to involve other people beside ourselves).
In my case, I am interested in photography first of all because I am a geek and love technology. Second, I love art, and photography lets me combine the tech and art aspects. Third, I like to photograph my family and the places I visit. Finally, I like the fact that my images are useful to other people: the athletes get to see the moments of their performance that otherwise only the spectators can enjoy, parents have memories of their kids practicing and performing dance numbers, etc.
Paradoxically, we do things we love mostly for ourselves, yet we seek external validation and are delighted by it.