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Tuesday, 23 March 2010

USE IT OR LOOSE IT APPLIES TO MEMORY

August 13, 2003

In his old age, American humorist Mark Twain once mused that his mental faculties had decayed such that he could remember only things that never happened.

"When I was younger, I could remember anything, whether it happened or not," Twain wrote. "But my faculties are decaying now and soon I shall be so I cannot remember any but the things that never happened. It is sad to go to pieces like this, but we all have to do it."

Modern science has confirmed Twain's conjecture--research shows that memory skills tend to decline dramatically in old age, with decreasing levels of accuracy and increasing errors. However, new research from Washington University in St. Louis suggests age-related cognitive decay may not be as inevitable as Twain contended.

"Our study suggests that the failing memories of older adults, including their tendency to remember things that never happened, are not an inevitable consequence of aging," said Henry L "Roddy" Roediger III, study co-author and James S McDonnell Distinguished University Professor at Washington University.

In research presented at the American Psychological Association meeting in Toronto, Roediger provides evidence that false memories and other cognitive declines often associated with normal aging can be more directly linked to measurable declines in executive control functions in frontal brain lobes.

"We tested a group of adults with an average age of 75 years and found that about one out of four had managed to avoid the memory declines so common in older adults," said Roediger. "Older adults who maintain high frontal lobe function were shown to have memory skills every bit as sharp as a group of college students in their early 20s."

Roediger, a leading expert on human memory, has focused recent research on understanding cognitive processes behind the creation of false memories, also known as memory illusions. Human memory, he explains, is not a storehouse of crystal clear, video images available for immediate and 100 percent accurate recall. Instead, memories are recalled through a constructive process that retrieves sights, sounds, words and other seemingly pertinent information, weighs their relevance to the memory task at hand, and then weaves them into a "best available" representation of a past experience.

Veridical memories are those that generally conform to reality--memories that provide a relatively true and accurate representation of a past experience. False memories occur when we remember events differently from the way they occurred, or in the most dramatic cases, when we remember events that never happened. False memories often result when we mistakenly merge elements of various past experiences or when imagination is used to fill holes in a sketchy recollection.

This explains why many instances of "sexual abuse" or "alien abduction" can be traced to early invasive hospital experiences. This is not to deny, of course, that child sexual abuse is common and real.

"There has been a lot of research in recent years that suggests deterioration in the prefrontal cortex is linked to age-related declines in veridical memory, but this is the first study to firmly establish a similar link to increases in false memories," Roediger said. "The idea that frontal lobe decline is associated with susceptibility to false memories is relatively new."

Several theories exist for why false memories increase with age. One suggests that older adults fail to properly encode information as an event is experienced or have problems retrieving and sorting such details during recall--a problem known as source monitoring. A related theory suggest frontal lobe problems make it difficult for older adults to focus attention on the memory task at hand and to effectively place retrieved information in context. That is, frontal lobe functioning underlies the ability to monitor accurately the source of information, and when frontal lobe declines, so does memory for the source of the events.

"If the frontal lobes are responsible for controlling attention or source monitoring, such that false memories can be distinguished from true memories, then we thought it possible that older adults with high frontal lobe function scores would not show greater false recall," Roediger said. "The idea here is that the increased susceptibility for memory illusions with older adults is carried by older adults with relatively low frontal lobe function. Our findings support this theory."

In other words, those who use their brain actively are less likely to be subject to false memories.

This story is based on a Washington University press release. The study has not yet been published.

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