Altruism as a result would be more along the lines of:
A wealthy individual that is quite famous as a philanthropist offers to give you 5 millions dollars. You have two choices. Keep it all to yourself, or you can give 50% of it to the charity of your choice as long as that charity is legitimate (aspca, cancer society, ms foundation, etc etc). Would you give 50 % or take it all for yourself?
Something like that.