A Glimpse Into Human Memory
Repeated glances build memories as well as sustained viewing
WEDNESDAY, July 25, 2001 (HealthDayNews) -- Taking a few glances at a room will produce just as strong a memory of the objects it contains as staring at its layout for a continuous time, says a new study.
The study, which appears in the July 26 issue of Nature, suggests that repeated glimpses may help people keep track of objects in the real world.
For example, memories developed from glancing around helps people remember where they put their car keys, says David Melcher, who conducted the study as a graduate psychology student at Rutgers University in Piscataway, N.J.
Previous studies have shown that short-term memory for such visual tasks is surprisingly poor.
"I was curious to see if there was some way that our memory for our visual surroundings is built up over time, since we know that memory is so bad immediately if you just see something for a few seconds. I thought that maybe over time, we start to remember the important things," without forming long-term memories, says Melcher.
"You don't want to remember as long-term memories everything that you ever see," he says. "There might be some sort of medium-term memory that would allow you to keep in mind the location of specific objects that might be useful for you."
To test his theory, Melcher showed six people (both men and women), aged 18 to the mid-30s, scenes of computer-generated "rooms" containing 12 unrelated objects. Each viewed the room for one, two, three or four seconds, either in spurts of 0.25 of a second, one second, two seconds or continuously. The glimpses could be interspersed by other unrelated scenes.
Melcher says those who viewed the scenes in brief, interrupted glimpses could ultimately remember almost exactly as many objects in the scene as the subjects who had a chance to view the scene for a continuous time.
Even interspersing other scenes with the scenes the subjects were trying to remember didn't affect performance, he says. However, the interruption scenes had to differ significantly from the other scenes, or they could confuse the subjects.
"There probably was some interference, but the amazing thing was that if you saw the same room soon enough, as in within a couple of minutes, then you started learning about that scene at the same point where you left it. So there was no loss for a couple of minutes." However, Melcher says he found some memory loss from day to day.
He found no difference between genders, but says that could be more clearly determined only with a study involving more participants.
Daniel Simons, an associate professor of psychology at Harvard University in Boston, says Melcher's paper touches on an interesting topic and deserves further study.
"The paper claims that some information is stored and built up over time. From a glance at a scene, you get some information, and you're actually storing it in a more or less visual form for a medium amount of time," says Simons.
"The idea is that when you glance at a room, for example, you don't need to look at everything all at once to be able to get a sense of what's there," he says. "You could take one glance and get some information, then take another glance and get more information. The more glances you get, the more information you get."
Simons says, "This question of how much visual information we retain over time is a very important one." A long-standing theory on how we view our environment is that we make constant, subtle adjustments to an existing mental model that we store in our brain all the time. But in the last two decades, some scientists have suggested that we don't store so much detail internally, he says.
"If you think of the World Wide Web, for example, there's really no reason to store every Web page in existence on your own computer. As long as you know how to point to the ones that are out there, you can get the information," says Simons. Some researchers have even suggested that we really don't need to store any information internally.
But Simons says this study steps back from that extreme in that it suggests that we do store some information. "We have a browser cache that stores some stuff so that it's accessible readily without having to go out to get it. That way, if the network goes down, you can still recall something useful," he says.
Melcher says he would like to pursue research into how this type of memory is influenced by aging or by memory disorders such as Alzheimer's disease, as well as whether this memory mechanism differs between children and adults.
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