Can Biased Search Results Change People’s Opinions About Anything at All? A Close Replication of the Search Engine Manipulation Effect (SEME)

Abstract

A series of experiments published in 2015 in the Proceedings of the National Academy of Sciences showed that search engine results favoring one candidate can (a) shift the preferences of undecided voters toward that candidate by up to 80% in some demographic groups and (b) be masked so people show no awareness of the manipulation. We labeled this phenomenon the Search Engine Manipulation Effect (SEME), and it appears to be one of the largest behavioral effects ever discovered. The 2015 experiments and others we have published since then have focused on shifts in voting preferences. In three new experiments with a total of 1,137 US residents (mean age = 33.2), we sought to determine whether biased search rankings could shift people’s opinions on topics that do not involve candidates or elections. Each of the new experiments looked at a different topic, and participants were pre-screened to make sure they didn’t have strong opinions about these topics. The topics were: Is artificial intelligence useful or dangerous? Is fracking helpful or dangerous? And: Are people born gay or do they choose to be gay? All participants were first asked various demographic questions, then shown brief summaries of the “pro” and “anti” views on each topic, and then asked their opinions about each topic. Next, participants were allowed to conduct an online search using our mock search engine (Kadoodle) lasting up to 15 minutes. All search results were real and linked to real web pages; only the order of search results varied from group to group. In each experiment, one-third of the participants saw biased search results favoring one perspective; one-third saw biased search results favoring the opposing perspective; and one-third (the control group) saw mixed search results. After completing their search, participants were again asked for their opinions about the topic. Our primary dependent variable was Manipulation Power (MP), the overall increase in the number of participants favoring one viewpoint after having viewed search rankings favoring that viewpoint. The MPs in the three experiments were 25.0%, 30.9%, and 17.8%, respectively. Corresponding shifts were also found for how persuasive participants found each viewpoint to be and for how much they trusted each viewpoint. We conclude that biased search rankings can impact more than voting preferences. It appears that search rankings favoring one viewpoint on a wide range of topics can cause people who have not yet formulated a strong opinion on such topics to adopt the favored perspective. If our findings prove to be robust, we are exposing what might be considered a fatal flaw in search engines, namely that even without human interference, search algorithms will inevitably alter the thinking and behavior of billions of people worldwide on perhaps any topic for which they have not yet formed strong opinions. With self-determining AIs being rapidly integrated into search algorithms, one might wonder whether the manipulative power of personalized, biased search results will be harnessed in coming years in ways that serve humanity’s interests.

Keywords: Search engines, search engine manipulation effect, SEME, online manipulation, manipulation power, VMP, MP