Rewarding children for helping others

Little kids feel good when they help others. They innately feel compassion for others and want to help. It seems we're born this way.

As adults we value this behaviour in our children and unwittingly probably seek to reward it some way. What happens then when children then get something in return for helping others? What happens to their intrinsic motivation to feel compassion? The desire to get credit for good deeds becomes an external reward. How often then do they want to help when they are not being given something tangible in return?

The human race benefits when we seek to help others because it feels good. The human race is harmed when we only help others to get something.