In the largest false memory study to date, 5,269 participants were asked about their memories for three true and one of five fabricated political events. Each f
"Study asks 5,269 people about fabricated political event. 50% remember the false event, 27% saw it on the news".
"In the largest false memory study to date, 5,269 participants were asked about their memories for three true and one of five fabricated political events. Each fabricated event was accompanied by a photographic image purportedly depicting that event. Approximately half the participants falsely remembered that the false event happened, with 27% remembering that they saw the events happen on the news. Political orientation appeared to influence the formation of false memories, with conservatives more likely to falsely remember seeing Barack Obama shaking hands with the president of Iran, and liberals more likely to remember George W. Bush vacationing with a baseball celebrity during the Hurricane Katrina disaster. A follow-up study supported the explanation that events are more easily implanted in memory when they are congruent with a person's preexisting attitudes and evaluations, in part because attitude-congruent false events promote feelings of recognition and familiarity, which in turn interfere with source attributions."
See also: Creating False Memories by Elizabeth F. Loftus http://faculty.washington.edu/eloftus/Articles/sciam.htm