by Patrick Appel

Discover tackles the question. Snippet:

Even harrowing memoriesthe so-called flashbulb memories that feel as if they have been permanently seared into the brainare not as accurate as we think. Less than a year after a cargo plane crashed into an Amsterdam apartment building in 1992, 55 percent of the Dutch population said they had watched the plane hit the building on TV. Many of them recalled specifics of the crash, such as the angle of descent, and could report whether or not the plane was on fire before it hit. But the event had not been caught on video. The “memory” shared by the majority was a hallucination, a convincing fiction pieced together out of descriptions and pictures of the event.

By the late 1990s, hundreds of psychology experiments suggested that the description of memory as a neurally encoded recapitulation of the past was so oversimplified as to completely miss the point. Instead of being a perfect movie of the past, psychologists found, memory is more like a shifting collage, a narrative spun out of scraps and constructed anew whenever recollection takes place. The science of memory was conflicted, with the neurobiological and psychological versions at odds. If a memory is wired into brain cellsa literal engraving of informationthen why is it so easy to alter many years after the fact? It took an outsider to connect the dots.

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