Raphael Boleslavsky and Christopher Cotton, in "Information and Extremism in Elections", American Economic Journal: Microeconomics 2015, 7(1): 165–207 (http://dx.doi.org/10.1257/mic.20130006165) report that "today's longer campaign cycles, filled with numerous televised debates and constant news reporting and social media coverage, are causing the rise of extremist politicians" (http://phys.org/news/2016-03-success-extremist-politicians.html). Are you accord or not with this? What is the main objection you have about this study?
http://dx.doi.org/10.1257/mic.20130006165
http://phys.org/news/2016-03-success-extremist-politicians.html