The reason people can approach animals in the wild more easily from a car than by foot may be due to an innate "life detector" tuned to the visual movements of an approaching predator’s feet, says Queen’s University psychologist Niko Troje.
"We believe this visual filter is used to signal the presence of animals that are propelled by the motion of their feet and the force of gravity," suggests Dr. Troje, Canada Research Chair in Vision and Behavioural Sciences.
Conducted with Dr. Cord Westhoff from the Ruhr-Universität Bochum in Germany, the study was funded by the Canada Foundation for Innovation and the German Volkswagen Foundation. It will be published on-line April 18 in the international journal Current Biology.
The researchers suggest this low level locomotion detector is part of an evolutionary old system that helps animals detect quickly – even on the periphery of their visual field – whether a potential predator or prey is nearby. "Research on newly hatched chicks suggests that it works from very early on in an animal’s development," says Dr. Troje. "It seems like their brains are ’hard wired’ for this type of recognition."
One impetus for starting this research several years ago was a question by his young daughter, who asked him why she could get so much closer to wild rabbits in their neighborhood while riding on her bicycle rather than on foot. "I didn’t have an answer for her then. Now, I think I have one," he says.
Dr. Troje’s Motion Capture Laboratory at Queen’s uses high speed cameras to track the three-dimensional trajectories of small reflective markers attached to the central joints of a person’s body. When the subject moves, these seemingly unstructured white marker dots become organized into meaningful images, from which observers can determine the gender, body build, emotional state, and other attributes.
In this study, Dr. Troje’s team used "point-light sequence" videos to display the electronically captured motion of cats, pigeons and humans. People were tested on whether they could tell the direction of movement when these cues were changed.
Scrambling the dots didn’t create a problem, but when the image was inverted, observers were unable to say if the animal was moving to the right or left. The researchers conclude that foot movement is an independent, important visual cue that another animal is nearby.
"The observation that it is relatively easy to get close to wild animals in a car, a canoe, or a similar vehicle might be due to the absence of the typical movement of the feet," says Dr. Troje. Similarly, the creeping movement of a hunting cat can be interpreted in terms of disguising the ballistic component in its locomotion, he adds.
"Our finding might also provide an explanation for seemingly irrational phobias towards animals that don’t fit the ballistic movement pattern of a proposed ’life detector’," he says. "Snakes, insects and spiders, or birds can generate pathological reactions not observed in response to ’normal’ animals."
Nancy Dorrance | EurekAlert!
The balancing act: An enzyme that links endocytosis to membrane recycling
07.12.2016 | National Centre for Biological Sciences
Transforming plant cells from generalists to specialists
07.12.2016 | Duke University
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:...
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...
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...
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...
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,...
16.11.2016 | Event News
01.11.2016 | Event News
14.10.2016 | Event News
07.12.2016 | Health and Medicine
07.12.2016 | Life Sciences
07.12.2016 | Health and Medicine