I have search alerts set up on a variety of sites for “theory of fun.” Today this little gem popped up: Rolighetsteorin. It translates as “theory of fun for safety” according to Google, and it appears to be a Volkswagen campaign in Sweden that is trying to use fun for social improvement.
This page is dedicated to the idea that something as simple as happiness is the absolute easiest way to get people to change. That it does not need to be more difficult than to make things a bit more fun to have to change for the better. Which does not matter as long as there is improvement. For yourself, the environment or whatever you want.
An example of what they mean: getting dramatically more people to take the stairs instead of the escalator (which of course, provides more cardiovascular benefit).
It is fun to see the expressions on people’s faces as they puzzle out why the stairs (or the garbage can that makes a whistling cartoon “falling from a great height” sound when you toss trash in it) are there. The stats seem to bear out that there is an effect.
I would posit that the trash can would have diminishing returns compared to the stairs, because the stairs have expressive potential and are more of a toy; the trash can will get old since there is only one input and one output.