MENTAL HEALTH

Forgot what you were just about to do? Here's why.

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If you’ve ever forgotten why you just entered a room, you know how fickle memory can be. One moment it’s obvious why you walked down the hall, and the next moment you’re standing there befuddled.

Here today, gone in a millisecond. At least that’s how we used to think about short-term, or working, memory. But a study just published in the journal Science tells a different story. A recent idea or word that you’re trying to recall has not, in fact, gone AWOL, as we previously thought. According to new brain-decoding techniques, it’s just sleeping.

“Earlier experiments show that a neural representation of a word disappeared,” said the study’s lead author, Brad Postle, a professor of psychology and psychiatry at the University of Wisconsin-Madison. But by using a trio of cutting-edge techniques, Dr. Postle and his team have revealed just where the neural trace of that word is held until it can be cued up again.

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Their study amends the long-standing view of how memory works. Until now, psychologists thought that short-term memory evaporates when you stop thinking about something, while long-term memory permanently rewires neural connections. The new research reveals a neural signature for a third type of memory: behind-the-scenes thoughts that are warehoused in the brain.

In the study’s four experiments, a total of 65 students viewed a pair of images—some combination of a word, a face or a cloud of moving dots—on a screen. During a 10-second period, the students were prompted to think about one of the two images they had seen. After a brief delay, they had to confirm whether a picture they saw matched one of the first two images.

Click for more from the Wall Street Journal.