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!
Biologists unravel another mystery of what makes DNA go 'loopy'
16.03.2018 | Emory Health Sciences
Scientists map the portal to the cell's nucleus
16.03.2018 | Rockefeller University
Animal photoreceptors capture light with photopigments. Researchers from the University of Göttingen have now discovered that these photopigments fulfill an...
On 15 March, the AWI research aeroplane Polar 5 will depart for Greenland. Concentrating on the furthest northeast region of the island, an international team...
The world’s second-largest ice shelf was the destination for a Polarstern expedition that ended in Punta Arenas, Chile on 14th March 2018. Oceanographers from...
At the 2018 ILA Berlin Air Show from April 25–29, the Fraunhofer Institute for Laser Technology ILT is showcasing extreme high-speed Laser Material Deposition (EHLA): A video documents how for metal components that are highly loaded, EHLA has already proved itself as an alternative to hard chrome plating, which is now allowed only under special conditions.
When the EU restricted the use of hexavalent chromium compounds to special applications requiring authorization, the move prompted a rethink in the surface...
At the ILA Berlin, hall 4, booth 202, Fraunhofer FHR will present two radar sensors for navigation support of drones. The sensors are valuable components in the implementation of autonomous flying drones: they function as obstacle detectors to prevent collisions. Radar sensors also operate reliably in restricted visibility, e.g. in foggy or dusty conditions. Due to their ability to measure distances with high precision, the radar sensors can also be used as altimeters when other sources of information such as barometers or GPS are not available or cannot operate optimally.
Drones play an increasingly important role in the area of logistics and services. Well-known logistic companies place great hope in these compact, aerial...
16.03.2018 | Event News
13.03.2018 | Event News
08.03.2018 | Event News
16.03.2018 | Earth Sciences
16.03.2018 | Physics and Astronomy
16.03.2018 | Life Sciences