Primarily, Motivations (like beliefs from Burning Wheel) in my game are used to drive goal setting or complicate things in interesting ways for the character.
But Im having a hard time backing that mechanically, particularly for the 'complicating' aspect.
The way I see it, having a mechanic that rewards acting on a motivation means people will hammer the button to get the food. But one of the interesting things about roleplaying is deciding under what circumstances your character will act on or break with their motivations. So rewarding only 'acting on' defeats that somewhat.
What Ive done is to reward either option - simply narrating considering the motivation during a decision is enough to get a reward. Which is explicitly what Id like the players to do, but the rule itself is kinda wishy-washy. It doesnt have a solid edge to it if you know what I mean. And its hard to get that edge because I dont want the player to make the decisions tactically based on a mechanical trade-off, I want them to make the decision according to the fiction that seem right to them.
Can you give something like this solid mechanical backing without destroying the waht you are trying to back up in the first place?
If so , how?