Dogs See the World in Living Color

By Becky Lang | July 17, 2013 12:42 pm

dogs foodWe humans may love to accessorize our pets with colored dishes, collars and toys, but the received wisdom is that dogs probably don’t care.

In earlier tests of color vision, scientists reported that color just wasn’t that crucial to dogs in their daily activities. However dogs have two types of cone photoreceptors in their retinas, meaning that they have about as much color vision as a color-blind human. And new research finds that they regularly rely on color cues.

With their two cone types dogs can see blues, greens and yellows, but not any reds and oranges. It has been thought that dogs rely more on brightness than color to differentiate objects.

Now a Russian research team has found, in a study of eight previously untrained dogs, that the animals overwhelmingly preferred using color as a cue rather than brightness.

The team, led by Anna Kasparson of the Russian Academy of Sciences, began with the dogs outdoors in natural daylight and worked with four colors on paper squares: light yellow, dark yellow, light blue and dark blue. The difference between the lighter and darker colors was stark, thereby ensuring that brightness was a factor in the dogs’ perception.

Going to the dogs

In the first ”training” stage of the experiment, researchers paired two papers that differed in both qualities—dark yellow went with light blue; light yellow went with dark blue. These markers were placed in front of feedboxes that contained raw meat—but crucially, only one of the boxes was unlocked. Over a series of trials the dogs learned to associate the meat with the one color it was consistently marked with. To reinforce the lesson, dogs each went through 90 total trials.

Then the researchers changed things around. Dogs that had been trained to associate dark yellow with a reward were now given two novel options: light yellow and dark blue. Their first choice of feedbox thus indicated whether the most salient quality, for them, was the color (yellow) or the brightness (dark) of the original marker.

Over a series of 10 tests, the dogs went for color matches more than 70 percent of the time. And for half of the dogs, color was what they based their decision on every single time. Thus they’d clearly memorized the color associated with the treat, not its brightness. The results are published in the Proceedings of the Royal Society B.

The study shows that dogs, as well as the many other mammals with two cone photoreceptors, may rely much more on color to perceive objects than was previously thought. Something to think about the next time you’re making fashion decisions for Fido.

CATEGORIZED UNDER: Living World, select
MORE ABOUT: vision
  • thelizblack

    I believe it completely… my dog’s favorite color appears to be green. He always goes for green toys, green tennis balls (over yellow even), and while he loves all his toys he’s obsessed with his green ones.

  • Maggie Harrison

    I think that dogs do react to color. Maggie will bark at anything dark green, dark blue or black. She seems to love yellow.

  • Val Brooker

    If dogs don’t see yellow and red, how do they avoid bee’s, wasps and other such coloured critters displaying danger? Which is a fair proportion of the worlds poisonous biting, stinging critters.

    • mjm

      Presumably, they can still see the light/dark striped pattern.

    • SKowalski

      How do color-blind humans avoid bees, wasps, etc…?

      • jkono29

        By running in the opposite direction!

  • andy silva

    I totally agree, my dog’s favorite color is orange and prefers yellow stuffed animals. But he likes any color cat.

  • colindenronden

    But they don’t appear to see television, whereas cats do some of the time.

  • http://blogs.discovermagazine.com C Giroux

    Great to see an article like this. Scientific discoveries that challenge the status quo need to be more widely published. It would be nice to see more articles about researchers who question past “knowns.”

    Science is becoming the new religion for many. Most researchers understand the limitations of their hypotheses and data. Unfortunately, many who read science articles casually regard the results of research to be unquestionable, as with the “word of God.” To these science faithful, fundamental understanding of the subject is not necessary to accept or reject a hypothesis (a fundamental requirement of any religion). Adequate research from “peer reviewed sources” takes on an air of infallibility; peer reviewed research does have numerous advantages assuring credibility, but is not infallible.

    Just remember, Galileo was sentenced to house imprisonment for supporting the Copernican view that the Earth orbited the Sun. To say “that was the church, not science, things are different now,” is to not understand the role of the church in that day. The most educated members of the community were the priests, vicars, bishops. They acted as teachers, doctors, wise men; the community came to hear them profess (professors). They were asked for advice on myriad subjects. They were often the only literate members of the community. They were mavens; they were the authority that most members of the community relied upon for accurate information. The Ptolemaic view (Earth in the center) was professed by these educated men. The proof was in the pudding: using the Ptolemaic view, the change of the seasons was accurately predicted; a crucial need for an agrarian society. To say anything else was to contradict 1500 years of PROVEN knowledge; knowledge that had fed 100 generations. The peer review process led to Galileo’s imprisonment.

    So, long story short, I like seeing new science that challenges old science, not just new research based upon existing ideas considered to be true.

  • http://motervation.wordpress.com/ kmote

    what in the world is “dark yellow”? Is that anything like “dark white”?

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