We predicted that the opinions and voting preferences of 2 or 3 per cent of the people in the two bias groups – the groups in which people were seeing rankings favouring one candidate – would shift toward that candidate. What we actually found was astonishing. The proportion of people favouring the search engine’s top-ranked candidate increased by 48.4 per cent, and all five of our measures shifted toward that candidate. What’s more, 75 per cent of the people in the bias groups seemed to have been completely unaware that they were viewing biased search rankings. In the control group, opinions did not shift significantly.