People in Rome remember the 2004 anti-war protest as peaceful. But when university students in the United States looked at photographs of the protest later, they called it violent and disturbing. What happened? Was it a cultural gap? No — it was a doctored photograph, much like the ones the New York Times ran of an Israeli air raid on Beirut with a lot of extra smoke billowing over the city. The doctored Rome picture was used for a new study that asked whether small changes made in photographs could transfigure the way people interpret events depicted in them.

Now there's scientific proof that a doctored photo can change history. Researcher Elizabeth Loftus altered a photo of the Rome protest, adding a person in a mask, and discovered that people took this tiny change as a sign that the protest had been combative. Apparently:

Participants who viewed the doctored photos said they were less inclined to participate in future protests.

Said Loftus, "It's potentially a form of human engineering that could be applied to us against our knowledge." Yeah, sort of like that Fnord thing.

Memory can be manipulated by photos [UC Irvine]