Humans are motivated by egoism and beloningness. Those are the usual assumtions concerning human behaviour. In a reseacrh on a very basic level I would like to introduce duty as the third driver of human action. I have applyed for external funding, but my ideas are not competetive. But I do not give up, so I have made one paper that organize some of my first thoughts and knowledge about duty. It can be downloaded here. If you have any comments and/or recommendations, please let me know ( Sven.Olof.Collin@lnu.se ).