Altruism motivation/behavior is when you help someone without expectations of benefit for yourself. On the other hand, egoistic motivation/behavior is when you help someone with expectations of benefit for yourself. For example, if you donate to charity where not many people would know about it, that would be altruism. But if you donate to charity in a way so that everyone would know, that might be egoistic. Egoistic behavior is kind of like a motivation of helping people.
People help people because as I said before, people might want to benefit out of that. People want to feel good.People also might help people because they were taught to. People also help people because they feel empathy. They know how it feels. Empathy can be a big factor of helping people. Also, us humans are suppose to help people in need. Helping is one if the big behaviors of humans. We were born to help people.
I helped a person with a small child(baby) by lending her a seat. I did this because in Japan, you are suppose to lend seats to people who need the seat. Also, I helped my parents by holding what we bought in the supermarket. I did this because they are my parents and I am suppose to help my family. This is in a way altruistic because I can’t benefit out of that and mainly I don’t really care if I benefit out of that or not.