Are dogs unable to see 2-D images (mirrors, photos, TV)?
You're a dog.
The guy you've lived with lo these many years (i.e., me) points out another dog on television. You couldn't care less.
He shows you a photograph of a snarling cur that would normally send you yelping for the hills. You yawn.
Pulling out all the stops, he puts you in front of a mirror to gaze upon your own countenance. Zippidy doo dah.
You prance merrily away, while your guy scratches his head. Is it possible that dogs can't see in two dimensions? If not, why not? And if they can, what kind of brain damage case is my pal??
Maybe he's just stricken with ennui. From what I can tell, dogs have no problem making out two-dimensional images--in fact, the real problem is they can't tell two-dimensional images from three-dimensional reality. For example, I've heard of one mutt who thought an especially lifelike doggie painting was the real McCoy. Being of a devious nature, the mutt attempted to sidle around to the backside of the painted dog, the better to go for the vitals. Naturally, this caused the mutt to run into the wall, whereupon he discovered that the painted dog had disappeared from view. Baffled, he ran back around to the front of the painting, whereupon the painted dog became visible again. This caused the mutt to totally freak. Another dog of my acquaintance has been known to bark at his canine cousins when they make an appearance on TV, and yet another likes to spend his time scratching away at his image in the mirror. (In the interest of strict accuracy, I should point out that a mirror image is three-dimensional, not a 2-D--the relative position of objects will shift as your perspective changes.) Not too bright, maybe, but they obviously don't suffer from any perceptual disabilities.