This an excellent short explanation for group decision dynamics. If this subject is of interest to you I strongly recommend: How We Decide https://www.amazon.com/How-We-Decide-Jonah-Lehrer/dp/0547247...

This subject, at least to me, calls into question the behavior associated with recent events. The subjects of police brutality, civil rights, systemic racism, and so forth are much older than two weeks. I appreciate there are people and groups who have been actively working for years to raise awareness of these concerns, and then there is everybody else. Many people in that second category are crazy impassioned about these subjects as seen in both HN activity as well as the protesting and riots seen in the media. If this segment of people are honestly that concerned and these subjects were clearly concerns for more than two weeks ago then were these peoples’ level of concern then? I suspect this sudden call to concern is more the result of contagious group behavior dynamics and social psychology than a premeditated cognitive concern of independent consideration.

If you're interested in stuff like this, check out 'How we decide' by Jonah Lehrer : http://www.amazon.com/How-We-Decide-Jonah-Lehrer/dp/06186201...

I'm reading it now, and it's an amazingly insightful book, in that it manages to at once explain the workings of the brain on a psychological and physiological level, for a whole different slew of "decisions" we humans make.