That's one of the things Storypath Ultra gives XP for. Every character has two short-term aspirations (what do they want to do in this session) and one long-term aspiration (what to they want to do on a moderate-term basis), in addition to a group aspiration (the more plot-relevant goal) set by the GM. A character gets 1 XP for attendance, 1 XP for achieving a short-term aspiration (with an additional XP if all characters achieve one in the same session, so you are encouraged to help the other players do their thing as well), 2 XP for a long-term aspiration, and 3 XP for a group aspiration. Short-term aspirations reset every session, but long-term ones only do so when everyone has completed theirs. There are also some other bonuses for spending metacurrency and overcoming obstacles.I guess I'm not understanding your definition of bias.
Players set their triggers to whatever it is they want their character to do. The fighter who wants to kill things and save the princess sets their triggers to killing things and saving the princess. The ranger sets their triggers to leading the group to the elven kingdom and spotting and avoiding danger when they're in the woods. The thief sets their triggers to disarming traps and looting the coin purses of rich nobles.
The game isn't telling them what to set their BIGs to, to gain XP. They're telling the game what they want it to give them XP for.
Short-term aspirations are things like "I want to solve a problem by talking" or "I want to find out a secret." Long-term aspirations are things like "I want to find out what happened to my brother" or "I want to make a deal with a daemon".







