  We present a many-body theory that explains and reproduces recent
observations of population polarization dynamics, is supported by controlled
human experiments, and addresses the controversy surrounding the Internet's
impact. It predicts that whether and how a population becomes polarized is
dictated by the nature of the underlying competition, rather than the validity
of the information that individuals receive or their online bubbles. Building
on this framework, we show that next-generation social media algorithms aimed
at pulling people together, will instead likely lead to an explosive
percolation process that generates new pockets of extremes.
