For instance, if someone were to make a decision based on which option would bring him the greatest reward, but would not have done the same thing if there were no reward, e.g., not doing chores or work unless they'll be rewarded or praised for doing so. I think this word therefore expresses never doing anything for its own sake: never working just because the work has to get done. This is a very specific word I'm looking for. I know how to use dictionaries and thesauri, so I'm not looking for simple words like "greedy" or "self-serving". And I know that such a word exists, I just can't remember it, so I'm not asking if there is one, I'm asking for help recalling what it is. Thank you so very much if you can help me.