Working in Movement

Remember Sammy Jankis. That's not a question, but a prominent line and part of the plot of the movie Memento. The key character in that movie suffered from head injury that left him unable to form long term memories. He could remember stuff that happened to him for about 15 minutes and then the memories vanished into thin air. This condition provided a monumental complication to his quest to find the guy who had killed his wife and inflicted the head injury that left him in this condition.

Instead of his brain, he used Polaroid pictures and tattoos as his long term memory. He'd write notes to himself on the back of the pictures; if it was something really important, he'd get it tattooed on his body. One of those tattoos was the Sammy Jankis phrase, a trigger to remember another guy with a similar condition.

In the end, the main character kills one of the other characters, relying on information from the tattoos and Polaroids. Did these artificial memories lead him to the right guy, or had he blown away an innocent man? Maybe yes, maybe no. It turns out that memory is a slippery thing, whether based in nervous system tissue or Polaroid paper.

Other Hollywood movies have used human memory as plot devices. Hitchcock gave us Spellbound, and who can forget Gov. Schwarzenegger in Total Recall? But these older movies used a simpler model of human memory, one based on the metaphor of memory as videotape or computer hard disk. Since memories are simply stored, bad guys can simply retrieve and alter them or just delete them.

What made for good storytelling in those films turns out to be just that--complete fiction. More recent research suggests that long term memory does not work like a computer at all. Instead of instant retrieval, memories may be re-created as needed, like taking a peek at the Polaroids in Momento. And they are malleable; they can change with each re-creation. Instead of a single storage site in the brain, memories might come together from the association of different parts of the brain. Hitch and Arnold entertained us with their films, but the scientific foundations they used were pretty flimsy.

The plot of a new movie, Eternal Sunshine of the Spotless Mind, incorporates some of the newer findings on the workings of memory. The basic device in this movie is the breakup of a relationship and the desire of the people involved to erase memories of it. There's a well written review on Kuro5hin.

What's interesting about this to me is memory's critical role in learning of all kinds. The guy writing the review put it down elegantly:

Yes, memory is fallible and frequently wrong; but the mutability and error in memory is how we learn. We highlight what is important to us, and blur out the rest. Memory is fallible and frequently painful, but it's all we've got.