While Facebook is taking heat for allegedly controlling how topics trend on the social media website, search engines like Google are being scrutinized on how their rankings of stories might sway voters.  

Some experts estimate that between 2.6 and 10.4 million votes could be shifted because of how search engines rank stories. According to psychologist Robert Epstein, who researches human-adjusted search engines, these shifts could be made “without leaving a paper trail.”  

Epstein explained his research and how an algorithm can reorder results to Salon:  “If you click on one of the top results, you connect through a web page that makes one candidate look better than another,” he told the magazine.  

“You can’t shift everybody — but you can shift the key people in a close election. There’s never been a more efficient way to shift swing voters than this — what we call SEME, Search Engine Manipulation Effect,” he said.  

In a piece for Quartz  in April, Epstein wrote that search rankings “probably” affect how people vote but “Because no one actually tracks search rankings, however — they are ephemeral and personalized, after all, which makes them virtually impossible to track — and because no whistleblowers have yet come forward from any of the search engine companies, we cannot know for sure whether search rankings are consistently favoring one candidate or another.”  

On Tuesday, Facebook agreed to come to Capitol Hill to brief the House Energy and Commerce Committee on their practices.  

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