Maura Styczynski sat ramrod straight before a computer screen at Duke University and tried hard to memorize where a series of colored squares flashed.

Such tests have long been used to assess people's short-term memory. But before finishing, Styczynski walked from the past to the future.

In a nearby genetics laboratory, a researcher pricked Styczynski's arm and extracted two vials of her blood. DNA collected from that blood, and from hundreds of other people, may deliver new clues to explain why some people can remember more than others.

Who doesn't know someone who struggles to learn a new cell number and someone else who recalls every phone number they've ever had? Or what about those people who can recite numbers thousands of decimal points long? Duke scientists are hunting for genes that explain the common variation in people's memory.

"We think variations in the mind may be wider than in other traits," said David Goldstein, director of Duke's Center for Evolutionary Genomics. "We want to understand normal."

If they succeed in linking memory skills to genetic patterns, the scientists could pinpoint what aspects of memory are likely to be inherited. The studies might also help explain what causes severe memory problems, such as those common to Alzheimer's disease. That might open doors to new medical treatments.

"If there's a gene that affects normal memory, a product of that gene is likely to be involved in illness, too," said Anna Need, a post-doctoral scientist leading the genomics center study.

Genes are the inherited codes that direct the performance of cells all over the human body, including the brain. When it comes to memory, no one expects that single genes are in command, Need said. Instead, using computer-aided statistics and instruments that read millions of DNA pairs, her team is looking for clusters of genes.

Cognitive psychologists, who have long tried to understand the human mind's workings, are eager to see what such genetic and brain imaging studies find, said Neil Mulligan, director of a graduate program in cognitive psychology at UNC-Chapel Hill.

Definitive results could answer some age-old questions about what aspects of the human mind result from nature or nurture. That could guide treatment.

"It's important to know what are the likely domains where therapy or medicines will be useful," Mulligan said.

But without the memory tests, genetic patterns won't make any sense. So in Goldstein's lab and at N.C. State University, Need's assistants put study subjects, paid $15 each, through a battery of trials. The point is to find each person's limit.

Styczynski did well. She correctly pronounced most of a long list of increasingly esoteric words that research technician Jill McEvoy handed her. She spotted important patterns in quick changing lists of numbers flashing on her screen. She recollected a good number of the abstract shapes she'd seen inside an ever-growing series of boxes.

When researcher McEvoy asked Styczynski to recite a long list of words she'd seen, Styczynski strained the limits of recall.

"Sneaker, bill, wife, student, umm let's see, fun, goodness, umm, I'm not sure," said Styczynski, a Duke junior.

Once Need's team analyzes its findings, it wants to make them available for other researchers to examine. It's impossible to predict, she said, what someone else might discover in the findings.

If important genes get discovered, Goldstein sees the opportunity to show the way to enhance memory -- something he thinks would appeal to many people.

"If it's one of the places where we vary the most, it might be one of the places where we could change ourselves the most," Goldstein said.

But the scientists know it may not be that simple. There could be trade-offs. Steps taken to sharpen one part of cognition might dull another, Need said. Or people who aren't good in one area may simply not have the genes needed to excel in all others.

Only one thing is certain.

"It's going to be complicated," Need said.

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