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!
Study identifies RNA molecule that shields breast cancer stem cells from immune system
23.05.2017 | Princeton University
“Pregnant” Housefly Males Demonstrate the Evolution of Sex Determination
23.05.2017 | Universität Zürich
An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.
We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...
Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.
Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...
An Australian-Chinese research team has created the world's thinnest hologram, paving the way towards the integration of 3D holography into everyday...
In the race to produce a quantum computer, a number of projects are seeking a way to create quantum bits -- or qubits -- that are stable, meaning they are not much affected by changes in their environment. This normally needs highly nonlinear non-dissipative elements capable of functioning at very low temperatures.
In pursuit of this goal, researchers at EPFL's Laboratory of Photonics and Quantum Measurements LPQM (STI/SB), have investigated a nonlinear graphene-based...
Dental plaque and the viscous brown slime in drainpipes are two familiar examples of bacterial biofilms. Removing such bacterial depositions from surfaces is...
23.05.2017 | Event News
22.05.2017 | Event News
17.05.2017 | Event News
23.05.2017 | Earth Sciences
23.05.2017 | Life Sciences
23.05.2017 | Physics and Astronomy