Can dogs see TV?
Haven't you always wondered?
Subject: Can dogs 'see' what's on tv like people can see?
Date: Fri Feb 20 13:01:46 1998
Posted by Peggy Borchers
Grade level: teacher/prof
School: Brazoswood High School
City: Clute State/Province: Texas
Country: USA
Area of science: Neuroscience
ID: 888001306.Ns
--------------------------------------------------------------------------------
Message:
I have read that dogs cannot really "see" television or their image in the mirror. We know they can hear the tv and can react to sounds on it. I read that dogs don't have the depth perception in their vision to see the screen as we see it or the mirror image as we see it. Have any studies been done on this?
***
Date: Wed Feb 25 08:24:55 1998
Posted By: Rick Huneke, D.V.M./M.P.H. Faculty, Division of Comparative Medicine, Washington University School of Medicine
Area of science: Neuroscience
ID: 888001306.Ns
--------------------------------------------------------------------------------
Message:
Dear Peggy:
Vision is a complicated process, and some of these processes are different in the way dogs see compared to the way people see. Since television was developed for people and not for dogs, aspects of dog vision were not considered.
One aspect of vision is sensitivity to flickering light. If a light is flickered fast enough, it appears as constantly illuminated light. Flickering light appears to fuse at approximately 50 Hz in people, while dogs can detect a much quicker flicker (up to 80 Hz). Because of this heightened sensitivity to flicker, a television program, in which the screen is updated 60 times per second and appears as a fluidly moving story to most humans, may appear to rapidly flicker to dogs.
Dogs also have depth perception, as anyone who has seen a dog jump a fence or catch a frisbee can attest to. However their field of depth perception is limited compared to humans. It takes two eyes looking at the same object (binocular vision) to have depth perception. Because both eyes face forward in man, we have a field of binocular overlap of about 140 degrees. In dogs, where the eyes face to the sides, the extent of binocular overlap is in the range of 30 to 60 degrees, thus their field of depth perception is only in front of them.
I don't know if dogs can see themselves in the mirror, but knowing dogs, I'm sure they wouldn't care what they looked like anyway!!
Reference: Miller, PE and Murphy,CJ, Vision in Dogs. Journal of the
American Veterinary Association. December 1995. 207 (12): 1623-1634.
origin: http://www.madsci.org/posts/archives/feb98/888431783.Ns.r.html
Subject: Can dogs 'see' what's on tv like people can see?
Date: Fri Feb 20 13:01:46 1998
Posted by Peggy Borchers
Grade level: teacher/prof
School: Brazoswood High School
City: Clute State/Province: Texas
Country: USA
Area of science: Neuroscience
ID: 888001306.Ns
--------------------------------------------------------------------------------
Message:
I have read that dogs cannot really "see" television or their image in the mirror. We know they can hear the tv and can react to sounds on it. I read that dogs don't have the depth perception in their vision to see the screen as we see it or the mirror image as we see it. Have any studies been done on this?
***
Date: Wed Feb 25 08:24:55 1998
Posted By: Rick Huneke, D.V.M./M.P.H. Faculty, Division of Comparative Medicine, Washington University School of Medicine
Area of science: Neuroscience
ID: 888001306.Ns
--------------------------------------------------------------------------------
Message:
Dear Peggy:
Vision is a complicated process, and some of these processes are different in the way dogs see compared to the way people see. Since television was developed for people and not for dogs, aspects of dog vision were not considered.
One aspect of vision is sensitivity to flickering light. If a light is flickered fast enough, it appears as constantly illuminated light. Flickering light appears to fuse at approximately 50 Hz in people, while dogs can detect a much quicker flicker (up to 80 Hz). Because of this heightened sensitivity to flicker, a television program, in which the screen is updated 60 times per second and appears as a fluidly moving story to most humans, may appear to rapidly flicker to dogs.
Dogs also have depth perception, as anyone who has seen a dog jump a fence or catch a frisbee can attest to. However their field of depth perception is limited compared to humans. It takes two eyes looking at the same object (binocular vision) to have depth perception. Because both eyes face forward in man, we have a field of binocular overlap of about 140 degrees. In dogs, where the eyes face to the sides, the extent of binocular overlap is in the range of 30 to 60 degrees, thus their field of depth perception is only in front of them.
I don't know if dogs can see themselves in the mirror, but knowing dogs, I'm sure they wouldn't care what they looked like anyway!!
Reference: Miller, PE and Murphy,CJ, Vision in Dogs. Journal of the
American Veterinary Association. December 1995. 207 (12): 1623-1634.
origin: http://www.madsci.org/posts/archives/feb98/888431783.Ns.r.html
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