"We now have evidence suggesting that on virtually all issues where people are initially undecided, search rankings are impacting almost every decision that people make."

I dug into his CV and found the following related works:

- recent publications: http://aibrt.org/index.php/internet-studies

- The search engine manipulation effect (SEME) and its possible impact on the outcomes of elections [http://aibrt.org/downloads/EPSTEIN_&_ROBERTSON_2015-The_Sear...]

A talk that he gave at Stanford about SEME: https://www.youtube.com/watch?v=TSN6LE06J54&feature=youtu.be

- Democracy At Risk Manipulating Search Rankings Can Shift Voters’ Preferences Substantially Without Their Awareness:[http://aibrt.org/downloads/EPSTEIN_and_Robertson_2013-Democr...]

CV: http://drrobertepstein.com/pdf/vita.pdf?lbisphpreq=1