After quite a while we throw another glimpse at the work of Prof Stephen Reicher, researcher of group behaviour at the University of St. Andrews.

Roger continues to explain the key aspects illustrating them with Donald Trump's methods and success as a leader.And we are going to learn the secret of being a leader which boils down to a pretty simple recipe afterall: group identity!

Other
One important concept mentioned only in passing is that of "othering" as explained in the introductory paragraph of this Wikipedia entry.