When designing this challenge I was thinking of all experiences I had interacting with people in my life. People act differently in groups and as individuals. People tend to trust their preconceptions of others based on their look.  The volume of the voice changes the conversation.

The experience is planned for 20 people who sign up online using their Facebook (or other social media) account. The group is formed of people who don’t have friends in common (in the social network).
All invited to the experience get together in a completely dark space where they are guided and seated by facilitators who use night vision equipment.

The space needed for the experience is very simple. It requires only one room. It has to be completely dark at the beginning of the experience. The experiment can be made in any school or club.
In the darkness, the group of 5 actors is mixed with participants.
Each two people are seated at small tables and are instructed to talk about anything they personally experienced. They can’t talk about their views. They can whisper only. Actors are introduced to share very personal stories that will help participants to open up and make the conversations deeper. After ten minutes the facilitators rotate the group again. The process is repeated 5 times. After 50 minutes they stand up and stay quiet. Facilitators take tables away and mix the group around the room. Actors leave and the light is turned on.
They have 2 minutes to walk around and look but they can’t speak. They shouldn’t be able to figure out who they spoke with.