One year ago, when I took care of my siblings (8; 12) for some days we visited our grandma. The kids love to be there and of course there is always something to eat between the classic meals (Candy, cake, fruits,...). The problem was that my siblings stood up from the table without clearing the table.
So I started with some short term extrinsic rewards to award good behavior like clearing the table, doing their homework, learning languages, and so on. Most things our parents asked me to take care of during their absence :-). So, I gave points for different activities and of course it depended also if my little sister (8) executed them or my little brother (12). Normally the tasks were easier to perform for him so he got less points. As a result he wanted to do more of them or even more difficult ones.
The collected points could be "redeemed" while we were playing board games or doing other activities. Playing "Ludo", the kids could use their points to buy a six or to get some extra steps. It was amazing to watch how they used their points. Sometimes they spent all these points in the bgeinnig to get a head start and sometimes they used the points more wisely and strategical during the whole game. They learned to use the points to cover some moves of the other players and so on.
But the most fascinating thing: Using this method for some days "clearing the table", for example, became a habbit and they also noticed that our grandma was very pleased to see what's happening. And so, the activity of clearing the table changed from a short-term, extrinsic motivated behavior to a long-term, intrinsic motivated behavior. Of course we already stopped giving points for all this activites bit they are still doing them.
I think it is an easy example for "using some kind of Trigger to get started first" and than, because there was more behind the activity (pleasing our grandma, pride) it became intrinsic motivated.
For me that's the purpose of Gamification