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Memory working?
POSTED 30 SEP 1999 Look at these numbers. How many of them do you remember? If you're like the average adult, it's between three and four if you didn't pay close attention to the numbers. If you used a mental strategy like grouping or silently repeating the numbers, you'd remember more than six. child serious

But a first grader would remember fewer than three without paying attention, and four if paying attention.

Before you start to trot out those boring "I forgot" excuses, let's explain why we're putting you through this torture. This is a test -- it is only a test -- of working memory, the stuff you keep in mind while trying to get something done.

I forgot! You never said that. I never heard about it.

Working memory is a temporary storage bin in the mind -- somewhat like a computer, only one with, say, .005 k capacity. Working memory holds an unfamiliar phone number while you dial. (If you're using the American system of three digits followed by four, you probably store phone numbers as two chunks: "555" and "1212".)

numbers flushing

Don't flush just yet!
Like the contents of a computer cache, the contents of working memory are eventually stored in long-term memory or flushed, making working memory available for future needs.

But exactly how much can we store in working memory? And is the storage capacity equal in adults and kids? Parents have, we note, observed that kids seem to have a limited ability to remember tasks. Tell a child watching a football game to do these things, and which do you think will be forgotten? kid staring at T.V. screen

  • Grab another candy bar

  • Please take your allowance from my wallet

  • Turn off the football game
It doesn't take a rocket scientist to answer this question, but does the fact that children remember, on average, one fewer item than adults reflect a difference in the brain, or merely that adults employ strategies to hold more items in working memory?

That's a question Nelson Cowan, a professor of psychology at the University of Missouri at Columbia, wanted to unravel. Working memory, he says, is important to innumerable human tasks, whether cerebral or occupational, but it's also limited."One of the most fundamental characteristics of the human mind is the limitation of working memory capacity. So far, at least, we have not known how this changes with age, and so we have not known just what to predict about a child's ability to solve a variety of problems at various ages."

In research published in the September/October issue of Child Development, Cowan and colleagues adapted a standard psychological test. Subjects -- in first grade, fourth grade or college -- heard a regular string of numbers while being asked to do a rhyming task. (The task required subjects to pick an object whose name rhymed with a picture on the computer screen.) The rhyming occupied the subjects' minds and deterred them from using strategies to boost recall. brain rhymes with drain
I remember that!
Periodically, subjects were asked to recall the last few numbers they'd heard. Oddly, they all remembered something, even though they were attending to the rhyming task rather than listening to the numbers. (This phenomenon, called "sensory memory," is like replaying a tape of the last few seconds of our environment, which is apparently recorded willy-nilly.) thinking kid

Guess what the results showed?

Groan-ups still did better than kids in the working memory department, indicating that the difference in capacity results not from strategy but from brain development. "Even when we prevented people from using the rehearsal strategy during reception, we found age differences that are almost as large " as found in studies that do not limit strategies, Cowan says.

The implications for parents: kids may actually not be able to grasp lists of things, whether directions or phone numbers. Breaking lists down into small chunks might be a good strategy for parents whose kids brains are still developing. Kids, Cowan points out, are not small adults, and can't be expected to act that way. then go there.
Have no fear: Inevitably your offspring will become more powerful, more brainy, and more beautiful.

-- David Tenenbaum

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