News Release
November 3, 2005
For Immediate Release
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Contact: Jeff Neu
(573) 882-3346
NeuJ@missouri.edu
In Short-Term Memory, Faster Is Not Better, MU Study Shows
COLUMBIA, Mo. — For years, researchers have said that the short-term memory span increases as children mature, which is important because memory span serves as an index for intelligence and mental maturation. It has been proposed that memory span increases because of growth in the speed of mental processing. Now, a researcher at the University of Missouri-Columbia has managed to dramatically increase the speed of spoken recall in children but, counter to speed-of-processing accounts, found no accompanying improvement in short-term memory.
"It has proven infeasible to train children to increase the maximum speed of recitation or rehearsal of words," said Nelson Cowan, an MU psychology professor. "However, until now, there has been no attempt to speed up recall itself."
Cowan used second-grade children and college students in the first experiment. The subjects were presented with random numbers one and nine either visually or verbally, and were asked to recall them in rapid fashion. Cowan found in the first experiment that the adults and children repeated lists much more quickly with rapid presentations of the list (two items per second) than with slower presentations (one item per second). However, the speed had no effect at all on either memory span or the post-span level of recall.
In the second experiment Cowan again used second-grade children. The biggest change in the experiment was that, in one group, the children were asked to repeat the number lists at whatever speed seemed best, while in the other the children were instructed to speak their responses as quickly as possible without making errors.
Cowan found that children could be taught to repeat lists at speeds much faster than they ordinarily use in immediate recall. The striking outcome was that this speed up did not improve recall accuracy at all, Cowan said. This outcome ran counter to what would be expected if the key constraint on memory recall is decay of a temporary memory representation that is strictly time-limited.
"The study helps support the theoretical view where capacity, rather than speed, may be the primary change in working memory over a person’s life span," Cowan said.
Cowan’s study will be published in the January edition of Psychological Science, a journal of the American Psychological Society.
Download the article. For more information, contact Jeff Neu at (573) 882-3346 or NeuJ@missouri.edu.
Psychological Science is ranked among the top 10 general psychology journals for impact by the Institute for Scientific Information. The American Psychological Society represents psychologists advocating science-based research in the public's interest.