Attention

People do some of their best work when they are in the spotlight. A prime example would be celebrities doing copious amounts of charity work. Would they have done those things if they were wealthy but not famous? Probably not because there is no incentive. When placed in the spotlight, people feel like if they do not do good for others, they will not goin any more praise.

(I also believe that humans are inherently evil as opposed to good so take that opinion of mine into consideration when contemplating this idea)