I think saying it will definitely happen is pretty widely accepted within social psychology. This is called group polarization, and it's the default state that

I think saying it will definitely happen is pretty widely accepted within social psychology. This is called group polarization, and it's the default state that you'll hit without very, very involved countermeasures: https://en.wikipedia.org/wiki/Group_polarization https://en.wikipedia.org/wiki/Group_polarization The wikipedia article is a very good summary of the phenomenon and the several factors that have a role in creating it.