Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Brightness discrimination in the dog

30.06.2004


Dogs’ ability to discriminate brightness is about half as good as that of humans, according to a study appearing in Volume 4, Issue 3 in the Journal of Vision. In research conducted by scientists from the Veterinary University of Vienna and the University of Memphis, dogs showed a surprising lack of ability to discriminate between grey cards that varied in brightness, says researcher Ulrike Griebel of the University of Memphis.



While a great deal is known about dogs’ visual acuity and the cellular components of their eyes, there is a paucity of information about their ability to discriminate brightness, says Griebel. Furthermore, she notes that there is relatively little information on how well other animals discriminate brightness.

The researchers tested three police dogs--two Belgian shepherds and a German shepherd. The dogs faced a series of pairs of grey squares, which differed in brightness. The task required the dog to determine how much the one square differed in brightness from the other. The correct choice was rewarded with a food treat. The dogs needed a far greater difference in brightness (known as the Weber fraction) than do humans to discriminate between two squares.


For the Belgian shepherds the Weber fraction was 0.27; for the German shepherd it was 0.22. Although the researchers did not test humans in their study, previous studies found that humans need a Weber fraction of 0.14 to be able to discern a brightness difference.

While there has been little research into brightness discrimination in animals, says Griebel, what has been found is surprising. Dogs are arrhythmic animals, meaning they are active during both day and night. Consequently, it would be expected that they would have a high level of brightness discrimination. Brightness would be an important cue for such animals. Like dogs, says Griebel, sea lions, a species of manatee, and the horse--all arrhythmic animals--are quite inferior to humans in the ability to discriminate brightness. Humans are diurnal animals--active primarily during daylight.

Griebel hypothesizes that the relatively poor brightness discrimination ability of these arrhythmic animals represents a compromise. Because their visual systems have to operate under a wide range of light conditions, something has to be given up. She says this idea is an initial supposition, and that more study is needed to arrive at a firmer conclusion. This research helps to show that dogs’ perceptual world is very different from ours, and that we cannot expect the same thing from them that we expect from ourselves.

Karen Schools Colson | EurekAlert!
Further information:
http://www.memphis.edu
http://www.arvo.org

More articles from Studies and Analyses:

nachricht New study from the University of Halle: How climate change alters plant growth
12.01.2018 | Martin-Luther-Universität Halle-Wittenberg

nachricht Disarray in the brain
18.12.2017 | Universität zu Lübeck

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: Artificial agent designs quantum experiments

On the way to an intelligent laboratory, physicists from Innsbruck and Vienna present an artificial agent that autonomously designs quantum experiments. In initial experiments, the system has independently (re)discovered experimental techniques that are nowadays standard in modern quantum optical laboratories. This shows how machines could play a more creative role in research in the future.

We carry smartphones in our pockets, the streets are dotted with semi-autonomous cars, but in the research laboratory experiments are still being designed by...

Im Focus: Scientists decipher key principle behind reaction of metalloenzymes

So-called pre-distorted states accelerate photochemical reactions too

What enables electrons to be transferred swiftly, for example during photosynthesis? An interdisciplinary team of researchers has worked out the details of how...

Im Focus: The first precise measurement of a single molecule's effective charge

For the first time, scientists have precisely measured the effective electrical charge of a single molecule in solution. This fundamental insight of an SNSF Professor could also pave the way for future medical diagnostics.

Electrical charge is one of the key properties that allows molecules to interact. Life itself depends on this phenomenon: many biological processes involve...

Im Focus: Paradigm shift in Paris: Encouraging an holistic view of laser machining

At the JEC World Composite Show in Paris in March 2018, the Fraunhofer Institute for Laser Technology ILT will be focusing on the latest trends and innovations in laser machining of composites. Among other things, researchers at the booth shared with the Aachen Center for Integrative Lightweight Production (AZL) will demonstrate how lasers can be used for joining, structuring, cutting and drilling composite materials.

No other industry has attracted as much public attention to composite materials as the automotive industry, which along with the aerospace industry is a driver...

Im Focus: Room-temperature multiferroic thin films and their properties

Scientists at Tokyo Institute of Technology (Tokyo Tech) and Tohoku University have developed high-quality GFO epitaxial films and systematically investigated their ferroelectric and ferromagnetic properties. They also demonstrated the room-temperature magnetocapacitance effects of these GFO thin films.

Multiferroic materials show magnetically driven ferroelectricity. They are attracting increasing attention because of their fascinating properties such as...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

10th International Symposium: “Advanced Battery Power – Kraftwerk Batterie” Münster, 10-11 April 2018

08.01.2018 | Event News

See, understand and experience the work of the future

11.12.2017 | Event News

Innovative strategies to tackle parasitic worms

08.12.2017 | Event News

 
Latest News

Let the good tubes roll

19.01.2018 | Materials Sciences

How cancer metastasis happens: Researchers reveal a key mechanism

19.01.2018 | Health and Medicine

Meteoritic stardust unlocks timing of supernova dust formation

19.01.2018 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>