WEDNESDAY, July 26, 2006 (HealthDay News) -- No wonder many busy people can't recall what they did yesterday.
A new study finds that learning while multi-tasking results in less available memory, later on, of the item learned.
"If you're learning things under distraction, what you're going to end up learning is going to be different and, in particular, is going to be a lot less flexible," said Russell Poldrack, senior author of the study and associate professor of psychology at the University of California, Los Angeles.
"Less flexible," in this case, means that the memory "will be more tied to the specific circumstances of when you learned it," and less prone to recall when those circumstances change, Poldrack said.
His team reported its findings in the current issue of Proceedings of the National Academy of Sciences.
Experts had already known that different forms of memory are processed by different systems in the brain.
"For the past 25 years, we have made great advances in delineating the different memory systems in the human brain," said Anthony Wagner, assistant professor of psychology and neuroscience at Stanford University. "Extensive data has shown that there is not a single learning memory system but actually multiple memory systems," he said.
Declarative memory, for instance, is the ability to recall lived experience, such as what you had for breakfast.
Procedural memories are more about learning how to do things, such as playing tennis or solving math problems.
"The fundamental questions beginning to capture the field are whether [these systems] interact and how they interact," Wagner said.
Poldrack's lab hypothesized that declarative and procedural memory might actually compete with each other.
To test that hypothesis, the researchers looked at how distraction or multi-tasking might cause a person to rely less on declarative memory and more on procedural memory.
That difference can be important. "Declarative memory is much more flexible," Poldrack explained. "If I ask you what you had for breakfast, it doesn't matter where you're standing. But if I ask you for a phone number, you might have to punch the numbers out with fingers. That's the only way you know how to do it."
In the study, Poldrack and his colleagues showed 14 adult volunteers cards with shapes on them and asked the volunteers to categorize the cards into one of two categories. Participants first performed the task on its own, and then again while doing something else at the same time. All the tasks were performed while participants were in an MRI scanner, so that the researchers could observe brain function.
Poldrack's group found that the things learned without distraction involved the declarative memory system.
On the other hand, "Things learned under distraction rely more on brain regions involved in procedural memory," Poldrack said. Those types of memories are tougher to bring up once the setting changes.
So, the bottom line for busy people is that, "When we learn to do things while we're multi-tasking, we're changing how our brain learns and the kind of knowledge we end up with," he continued. "It's not necessarily a good change. Our knowledge becomes less flexible, or tied to that particular situation, so we can't get to it in other situations."
Wagner said the study "supports the position that declarative memory would be hindered by divided attention."
More information
For more on memory and memory loss, head to the American Academy of Family Physicians.
