Our Brains

Much of our memory's work takes place while we're asleep, reports The Economist (2/2/13). A paper by Robert Stickgold of Harvard University and Matthew Walker of the University of California, Berkeley, proposes that "sleep acts as a form of triage -- first choosing what to retain and then selecting how it will be retained." What they found was that "sleep does indeed help people discard information they have been told to forget."

They also found that sleep "helps guide memories intended to be retained down particular paths -- remembering patterns, for example, as opposed to facts." Two studies found that only babies who had the opportunity to take a nap could later recall patterns of fake grammar to which they had been earlier exposed. A separate paper, by Matthew Walker and Bryce Mander, meanwhile looked "into the matter of forgetting, by comparing the process in the young and the old."

Not surprisingly, they found that older people (those in their 60s and 70s) did not retain nonsensical word pairs as well as younger people (those in their teens and 20s), both when tested immediately and after some sleep (the oldsters did even worse after sleep). Of course, older people don't need to remember as much as the younger, given that "they are already familiar with so much of what they experience. So it may be that their inability to form new memories is not a bug, but a feature."