Humans rarely move their eyes smoothly. As our eyes flit from object to object, the visual system briefly shuts off to cut down visual "noise," said Steven J. Luck, professor of psychology at the UC Davis Center for Mind and Brain. So the brain gets a series of snapshots of about a quarter-second, separated by brief gaps.
The working memory system smoothes out this jerky sequence of images by retaining memories from each snapshot so that they can be blended together. These memories typically last just a few seconds, Luck said.
"We use working memory hundreds of thousands of times each day without noticing it," Luck said. The system also seems to be linked to intelligence, he said.
Luck and postdoctoral researcher Weiwei Zhang wanted to test whether working memory stores a fixed, limited number of high-resolution images, or is a more fluid system that can store either a small number of high-resolution images or a large number of low-resolution images.
They showed volunteers a pattern of colored squares for a tenth of a second, and then asked them to recall the color of one of the squares by clicking on a color wheel. Sometimes the subjects would be completely unable to remember the color, and they just clicked at a random location on the color wheel. When subjects could remember the square, however, they usually clicked on a color that was quite close to the original color.
Zhang developed a technique for using these responses to quantify how many items a subject could store in memory and how precise those memories were.
"It's a trivial task, but it took us years to realize that we should use it," Luck said. The researchers began the work at the University of Iowa; Luck moved to UC Davis in 2006, and Zhang in 2007.
The evidence shows that working memory acts like a high-resolution camera, retaining three or four features in high detail. Those features allow the brain to link successive images together. However, while most digital cameras allow the user to choose a lower resolution and therefore store more images, the resolution of working memory appears to be constant for a given individual. Individuals do differ in the resolution of each feature and the number of features that can be stored.
People who can store more information in working memory have higher levels of "fluid intelligence," the ability to solve novel problems, Luck said. Working memory is also important in keeping track of objects that are temporarily blocked from view, and it appears to be used when we need to recognize objects shown in unfamiliar views.
Work by Lisa M. Oakes, another psychology professor at UC Davis and colleagues has shown that very young infants have fairly primitive working memory abilities. Between the ages of 6 and 10 months, however, they rapidly develop a much more adult-like working memory system.
Outside the visual domain, working memory is used for storing alternatives or intermediate values, for example when adding a string of numbers together, Luck said. It also appears to play an important role in learning new words, perhaps by allowing the sound of a new word to remain active in the listener's brain until a long-term memory of the word can be formed.
Luck compared the working memory system to the internal memory registers on a computer chip that allow it to make a series of calculations in between referring to the main memory. Our more familiar long-term memory, in contrast, can be used to store large quantities of information for long periods of time, but it is accessed much more slowly, like a computer's hard drive.
Luck and Zhang are now interested in how working memory operates in people with conditions such as attention deficit/hyperactivity disorder and schizophrenia, and those who have problems in perception and cognition. The paper is published online April 2 by the journal Nature, and the work was supported by grants from the National Institute of Mental Health.
Andy Fell | EurekAlert!
Diagnoses: When Are Several Opinions Better Than One?
19.07.2016 | Max-Planck-Institut für Bildungsforschung
High in calories and low in nutrients when adolescents share pictures of food online
07.04.2016 | University of Gothenburg
Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.
"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...
In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.
A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...
By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.
"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...
COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.
In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...
'Ferroelectric' materials can switch between different states of electrical polarization in response to an external electric field. This flexibility means they show promise for many applications, for example in electronic devices and computer memory. Current ferroelectric materials are highly valued for their thermal and chemical stability and rapid electro-mechanical responses, but creating a material that is scalable down to the tiny sizes needed for technologies like silicon-based semiconductors (Si-based CMOS) has proven challenging.
Now, Hiroshi Funakubo and co-workers at the Tokyo Institute of Technology, in collaboration with researchers across Japan, have conducted experiments to...
14.10.2016 | Event News
14.10.2016 | Event News
12.10.2016 | Event News
21.10.2016 | Health and Medicine
21.10.2016 | Information Technology
21.10.2016 | Materials Sciences