After hearing JIngjie's experience about physical interaction with an art piece, I recalled a similar experience in SF MOMA. Instead of "special people", there are "two birds on a pure sky" on those posters. And visiter's reactions are quiet interesting too, because they will follow the people in front of them each by each and lower their bodies and roll the poster really slow like they are doing a ritual thing. .
Just a thought, "Interacting with people's emotion?"