Thank you very much for your comment @richq11.
Well there are two different perspectives: the author´s point of view and the reader´s point of view. Both can receive rewards for their contribution - sometimes even in relation to the same piece of content. One publishs and one votes. I hereby wanted to focus on the rewards given to the audience.
But keeping with your example: humor is a very strong emotion. If you can make a person laugh, you provide him or her with a considerable value. So the reward should be accordingly - independently from the author´s invest. Quality is a personal issue - and that´s what makes a rewarding system actually that complex.