Form groups according to initial opinions

[mt-digital]

Part of the stubborn extremist hypothesis and our replication step involves correlating opinion shift with initial group opinion. We want to try to put like-minded people together to get groups with more or less extreme initial opinions.

It's not for sure we want to do this, as groups with different initial extremities will emerge naturally. But it was part of the procedure I imagined, so it's here for now.