Featured Research

from universities, journals, and other organizations

Some Short-term Memories Die Suddenly, No Fading

Date:
April 30, 2009
Source:
University of California - Davis
Summary:
Researchers have found that the temporary, working memories that the brain uses to process visual information may last for several seconds with little or no loss of precision. After that, they begin to wink out, but remain accurate until they disappear.

The human brain stores some kinds of memories for a lifetime. But when our eyes are open and looking at things, our gray matter also creates temporary memories that help us process complex tasks during the few seconds these visual memories exist. For decades, scientists have held that such short-term memories don’t suddenly disappear, but grow gradually more imprecise over the course of several seconds.

Now researchers at the University of California, Davis, have found just the opposite. Their subjects retained temporary memories of an object’s color or shape for at least four seconds. After that, the memories began to wink out like streetlights at daybreak, remaining quite accurate until they suddenly disappeared.

To test the accuracy of short-term visual memory, Weiwei Zhang, a postdoctoral scholar, and Steve Luck, a professor of psychology, both at the UC Davis Center for Mind and Brain, devised a pair of tests, both of which could separately measure two things: the accuracy of a short-term memory and the probability that the memory still existed. Each test was given to 12 adults.

In the first test, three squares — each with a different color fill — flashed for a tenth of a second on a computer screen. After an interval of one, four or 10 seconds a wheel showing the entire spectrum of colors appeared on the screen. The three squares also reappeared, only now they were colorless and one of them was highlighted. Subjects were asked to recall the color of the highlighted square and click on the area of the wheel that most closely matched it. Each subject repeated this test 150 times for each of the three memory retention intervals.

When subjects retained a memory of the color, they clicked very close to it on the wheel — the distance between the click and the actual color indicating the accuracy of the memory. When color had disappeared from memory, however, subjects clicked at random on the wheel.

The second test was similar to the first, but used shapes instead of colors.

Published in the April issue of the journal Psychological Science, the study found that subjects “either had the memory or didn’t have the memory,” Luck said, “and the probability of having it decreased between four and ten seconds. The memories did not gradually fade away.”

The finding provides insight into the underlying mechanisms behind memory formation and retention. “The memories are not like flashlights that get progressively weaker as the battery runs low,” Luck said. “They are more like a laptop computer that continues working at the same speed until it suddenly shuts down.” This could be important in everyday life, he explained, because it would provide a mechanism to help us avoid the confusion that might arise if we tried to make decisions on the basis of weak, inaccurate memories.

Zhang and Luck are currently incorporating these findings into a study of short-term memory dysfunction in people with schizophrenia.

The research was supported by a grant from the National Institute of Mental Health.


Story Source:

The above story is based on materials provided by University of California - Davis. Note: Materials may be edited for content and length.


Cite This Page:

University of California - Davis. "Some Short-term Memories Die Suddenly, No Fading." ScienceDaily. ScienceDaily, 30 April 2009. <www.sciencedaily.com/releases/2009/04/090429091806.htm>.
University of California - Davis. (2009, April 30). Some Short-term Memories Die Suddenly, No Fading. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2009/04/090429091806.htm
University of California - Davis. "Some Short-term Memories Die Suddenly, No Fading." ScienceDaily. www.sciencedaily.com/releases/2009/04/090429091806.htm (accessed September 16, 2014).

Share This



More Mind & Brain News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

FDA Eyes Skin Shocks Used at Mass. School

FDA Eyes Skin Shocks Used at Mass. School

AP (Sep. 15, 2014) The FDA is considering whether to ban devices used by the Judge Rotenberg Educational Center in Canton, Massachusetts, the only place in the country known to use electrical skin shocks as aversive conditioning for aggressive patients. (Sept. 15) Video provided by AP
Powered by NewsLook.com
Shocker: Journalists Are Utterly Addicted To Coffee

Shocker: Journalists Are Utterly Addicted To Coffee

Newsy (Sep. 13, 2014) A U.K. survey found that journalists consumed the most amount of coffee, but that's only the tip of the coffee-related statistics iceberg. Video provided by Newsy
Powered by NewsLook.com
'Magic Mushrooms' Could Help Smokers Quit

'Magic Mushrooms' Could Help Smokers Quit

Newsy (Sep. 11, 2014) In a small study, researchers found that the majority of long-time smokers quit after taking psilocybin pills and undergoing therapy sessions. Video provided by Newsy
Powered by NewsLook.com
'Fat Shaming' Might Actually Cause Weight Gain

'Fat Shaming' Might Actually Cause Weight Gain

Newsy (Sep. 11, 2014) A study for University College London suggests obese people who are discriminated against gain more weight than those who are not. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins