It is always a challenge to remember a new computer password after an old one has expired, or to memorize a new phone number.
That is because the brain is competing to recall old memories and new ones that are associated with the same thing, researchers from Yale and Stanford report in Proceedings of the National Academy of Sciences.
Brice Kuhl, a psychologist at Yale, and his colleagues found that when the brain is cluttered with similar events, the difficulty in recalling just one of them is visible through the brain-scanning technology known as functional magnetic resonance imaging.
The researchers provided subjects with words that had both face associations and scene associations. When they ran a scan and asked the subjects to recall the association they had most recently seen, blood flowed in parts of the brain that are used to recall faces and scenes.
Most people regularly encounter this competition.
“I park in a garage every day at work, and I park in a different space every day, depending on availability,” Dr. Kuhl said. “And I very often walk to where I parked the day before. It’s not that I totally forgot where I parked, it’s just that I still remember yesterday’s spot.”
