In “Just My Imagination,” the Temptations sang of a vision that “couldn't be a dream, for too real it all seems.” Scientists now have pinpointed how the imagination can make false memories. Volunteers lying in a magnetic resonance imaging scanner were shown a list of words and told to picture each item. For half the words, a photograph of the matching object was flashed. Afterward, volunteers listened to a random sequence of words corresponding either to photographs they saw, to objects they were only told to imagine, or to items neither seen nor imagined. When volunteers falsely remembered seeing photographs of objects they had only imagined, brain regions critical to generating images became highly activated. Mental images created by these areas leave traces in the brain that are later mistaken for objects actually perceived, suggest researchers at Northwestern University in the October Psychological Science.
This article was originally published with the title "Alternative Reality" in Scientific American 292, 1, 29 (January 2005)