Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How visual cues help us understand bodily motion

08.07.2011
"Our visual system is tuned towards perceiving other people. We spend so much time doing that—seeing who they are, what they are doing, what they intend to do," says psychology professor Nikolaus F. Troje of Queen's University in Kingston, Ontario.

This process is called biological motion perception, and humans are so good at it that even a few dots on a screen representing the major joints of a body are enough to retrieve all the information we need—as long as they move.

But what role does motion play in that process? Does the visual system use it only to connect the dots to create a coherent, or "global," structure? Troje and his colleagues—Masahiro Hirai and Daniel R. Saunders at Queen's, and Dorita H. F. Chang, now at the University of Birmingham, UK—investigated this question in a new study, to be published in an upcoming issue of Psychological Science, a journal of the Association for Psychological Science.

They presented their participants with computer-generated stimuli showing 11 light points representing the shoulder, hip, elbows, wrists, knees, and ankles of a person walking, as on a treadmill. After a two-second display, the observers had to indicate which direction they believed the walker was facing.

This is an easy task, and the participants performed it almost without fail—even though the point-light walker was masked with 100 randomly placed additional dots. But they were also able to do it if the global structure of the body was entirely disrupted by randomly scrambling the 11 dots. "The local motion of individual dots contained enough information about the walker's facing direction," says Troje.

But when the whole thing was turned upside-down, the participants could no longer discern which way the figure was walking. Why? Says Troje: "The visual system uses the information contained in these local dot movements—mainly the ones of the feet—only when it is validated by additional properties that do not in themselves carry any information about facing direction"—in this case the proper vertical orientation, feet on the bottom, head on top.

An observer can't tell the facing direction of a stationary upright figure. But put the local motion together with an upright position, even mix up and mask all the light points. And "direction discrimination of these 'scrambled' walkers is almost as good as with structurally coherent walkers," Troje says.

Why is the visual system so acute even when the shape of a figure is totally broken down? To survive, we have to be able "to detect the presence of a living being in the visual environment—regardless of whether it is a fellow human, a potentially dangerous predator, or even a prey animal," says Troje. "For that purpose, we need a detection mechanism that is independent of the particular shape of an animal."

Parsing these effects can help us understand—and appreciate—our extraordinary perceptual assets. "It tells us how sophisticated our visual system is in using information about the structure, the physics, and the regularities of the visual world," he says.

For more information about this study, please contact: Nikolaus F. Troje at troje@queensu.ca.

The APS journal Psychological Science is the highest ranked empirical journal in psychology. For a copy of the article "Body configuration modulates the usage of local cues to direction in biological motion perception" and access to other Psychological Science research findings, please contact Divya Menon at 202-293-9300 or dmenon@psychologicalscience.org.

Divya Menon | EurekAlert!
Further information:
http://www.psychologicalscience.org

Further reports about: Psychological Science Science TV local motion visual system

More articles from Studies and Analyses:

nachricht Multi-year study finds 'hotspots' of ammonia over world's major agricultural areas
17.03.2017 | University of Maryland

nachricht Diabetes Drug May Improve Bone Fat-induced Defects of Fracture Healing
17.03.2017 | Deutsches Institut für Ernährungsforschung Potsdam-Rehbrücke

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: Giant Magnetic Fields in the Universe

Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.

The results will be published on March 22 in the journal „Astronomy & Astrophysics“.

Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...

Im Focus: Tracing down linear ubiquitination

Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.

Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...

Im Focus: Perovskite edges can be tuned for optoelectronic performance

Layered 2D material improves efficiency for solar cells and LEDs

In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...

Im Focus: Polymer-coated silicon nanosheets as alternative to graphene: A perfect team for nanoelectronics

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.

Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...

Im Focus: Researchers Imitate Molecular Crowding in Cells

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to simulate these confined natural conditions in artificial vesicles for the first time. As reported in the academic journal Small, the results are offering better insight into the development of nanoreactors and artificial organelles.

Enzymes behave differently in a test tube compared with the molecular scrum of a living cell. Chemists from the University of Basel have now been able to...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

International Land Use Symposium ILUS 2017: Call for Abstracts and Registration open

20.03.2017 | Event News

CONNECT 2017: International congress on connective tissue

14.03.2017 | Event News

ICTM Conference: Turbine Construction between Big Data and Additive Manufacturing

07.03.2017 | Event News

 
Latest News

Argon is not the 'dope' for metallic hydrogen

24.03.2017 | Materials Sciences

Astronomers find unexpected, dust-obscured star formation in distant galaxy

24.03.2017 | Physics and Astronomy

Gravitational wave kicks monster black hole out of galactic core

24.03.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>