Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Psychologist finds instance where ’two wrongs do make a right’

26.10.2004


UO study shows the distinction between perception and action streams is oversimplified



A trusted mental map of your surroundings turns out to be slightly misaligned, skewing your orientation. Your ability to control the direction in which you move is similarly compromised, although in a manner opposite the map’s offset. Taken together, the errors cancel one another, and you end up exactly where you want to be. Contrary to the proverb, two wrongs do make a right. This exception is the rule when it comes to how our brain processes what our eyes see and where our body moves, according to a discovery by University of Oregon researchers Paul Dassonville and Jagdeep Kaur Bala that will appear in the November issue of the journal PLoS Biology.

Their study, funded by the National Science Foundation, challenged a dominant theory of how the brain processes vision. The theory holds that information from the eyes separates into two distinct streams: one to simply represent where we see things in the environment, and another to guide the physical movements of our body within that environment. Both processes have been thought to depend largely on accessing distinct maps of the environment within the brain, representing objects from varying locations in our field of vision by systematically varying activity in corresponding regions of the brain. "It’s starting to look like the distinction between perception and action streams is an oversimplification," says Dassonville, an assistant professor of psychology. "There appear to be as many as 40 different visual areas, many of which contain some type of spatial map, each with its own idiosyncratic pattern of errors. Different tasks draw on different subsets of maps."


To untangle these error-prone maps, the researchers employed an illusion known as the induced Roelofs effect. People were briefly shown a bright spot, surrounded by a large rectangular frame, and were asked to say where they thought the spot appeared. If the frame was shifted to the observer’s right or left, the perceived location of the spot was shifted in the opposite direction. However, when observers were asked to physically point toward the spot, they did so with very little error. "Perception is prone to the illusion, while action seems immune," explains Dassonville, echoing the commonly accepted axiom that separate visual systems drive perception and action.

However, the UO study revealed that slight manipulations of the illusion led to a wholly new realization. In fact, the illusion actually distorted observers’ perceptions of where "straight ahead" was with respect to their own bodies, ultimately affecting both perception and action. "The ’wrong’ perception of where the object appeared was offset by the opposing ’wrong’ pointing movement that was based on the body’s distorted sense of its own position. As a result, the ’right’ pointing movements are made in spite of an inaccurate sense of the visual scene," Dassonville explains.

While we still lack a complete picture of how the brain converts visual input into motor output, Dassonville says, these findings enhance our understanding of the most fundamental concepts of how we experience and interact with the world. Dassonville and Elizabeth Walter, a graduate student, are now using the functional magnetic resonance imaging (fMRI) resources of the University of Oregon’s Robert and Beverly Lewis Center for NeuroImaging to identify brain mechanisms related to the effects described in the PLoS Biology article.

Dassonville joined the UO faculty in 1999. In addition to his appointment in the psychology department, he is a member of the university’s Institute of Neuroscience. Bala is continuing her research on the effects of attention on visual perception in the laboratory of UO psychology professor Richard Marrocco.

PloS Biology, first published in 2003, is the flagship journal of the Public Library of Science, a nonprofit organization of physicians and scientists dedicated to widespread, free access to scientific and medical literature.

Melody Ward Leslie | EurekAlert!
Further information:
http://www.uoregon.edu

More articles from Studies and Analyses:

nachricht Amputees can learn to control a robotic arm with their minds
28.11.2017 | University of Chicago Medical Center

nachricht The importance of biodiversity in forests could increase due to climate change
17.11.2017 | Deutsches Zentrum für integrative Biodiversitätsforschung (iDiv) Halle-Jena-Leipzig

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Scientists channel graphene to understand filtration and ion transport into cells

Tiny pores at a cell's entryway act as miniature bouncers, letting in some electrically charged atoms--ions--but blocking others. Operating as exquisitely sensitive filters, these "ion channels" play a critical role in biological functions such as muscle contraction and the firing of brain cells.

To rapidly transport the right ions through the cell membrane, the tiny channels rely on a complex interplay between the ions and surrounding molecules,...

Im Focus: Towards data storage at the single molecule level

The miniaturization of the current technology of storage media is hindered by fundamental limits of quantum mechanics. A new approach consists in using so-called spin-crossover molecules as the smallest possible storage unit. Similar to normal hard drives, these special molecules can save information via their magnetic state. A research team from Kiel University has now managed to successfully place a new class of spin-crossover molecules onto a surface and to improve the molecule’s storage capacity. The storage density of conventional hard drives could therefore theoretically be increased by more than one hundred fold. The study has been published in the scientific journal Nano Letters.

Over the past few years, the building blocks of storage media have gotten ever smaller. But further miniaturization of the current technology is hindered by...

Im Focus: Successful Mechanical Testing of Nanowires

With innovative experiments, researchers at the Helmholtz-Zentrums Geesthacht and the Technical University Hamburg unravel why tiny metallic structures are extremely strong

Light-weight and simultaneously strong – porous metallic nanomaterials promise interesting applications as, for instance, for future aeroplanes with enhanced...

Im Focus: Virtual Reality for Bacteria

An interdisciplinary group of researchers interfaced individual bacteria with a computer to build a hybrid bio-digital circuit - Study published in Nature Communications

Scientists at the Institute of Science and Technology Austria (IST Austria) have managed to control the behavior of individual bacteria by connecting them to a...

Im Focus: A space-time sensor for light-matter interactions

Physicists in the Laboratory for Attosecond Physics (run jointly by LMU Munich and the Max Planck Institute for Quantum Optics) have developed an attosecond electron microscope that allows them to visualize the dispersion of light in time and space, and observe the motions of electrons in atoms.

The most basic of all physical interactions in nature is that between light and matter. This interaction takes place in attosecond times (i.e. billionths of a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

AKL’18: The opportunities and challenges of digitalization in the laser industry

07.12.2017 | Event News

 
Latest News

Midwife and signpost for photons

11.12.2017 | Physics and Astronomy

How do megacities impact coastal seas? Searching for evidence in Chinese marginal seas

11.12.2017 | Earth Sciences

PhoxTroT: Optical Interconnect Technologies Revolutionized Data Centers and HPC Systems

11.12.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>