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 Smart Data Transformation – Surfing the Big Wave
02.12.2016 | Fraunhofer-Institut für Angewandte Informationstechnik FIT

nachricht Climate change could outpace EPA Lake Champlain protections
18.11.2016 | University of Vermont

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: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

 
Latest News

Closing the carbon loop

08.12.2016 | Life Sciences

Applicability of dynamic facilitation theory to binary hard disk systems

08.12.2016 | Physics and Astronomy

Scientists track chemical and structural evolution of catalytic nanoparticles in 3-D

08.12.2016 | Materials Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>