I have been an avid dog lover all my life, but I don't think I've ever met a dog as smart as this one. I viewed a documentary about dogs and did a little more research on one of the dogs they talked about. It was a 6 year old border collie named Chaser, and she new the names of over 1,000 different items! How is this possible?? Well, her owner, John Pilley, used what he calls a "successive technique" to teach Chaser the names of all the toys. He would teach Chaser one toy, and once she was able to learn that object, he would move on to the next, and repeat that process with more and more toys and objects. After teaching Chaser the names of the toys, he would put a pile of toys in another room, and call out what toy he specifically wanted. And by much surprise, Chaser would come back with the correct toy! After successfully grabbing the correct toy, he would let her play with "Blue," a small ball she would chase around. Border collies are one of the smartest breeds of dogs out there, but I had no idea they could reach this level. If you don't believe me, below is a link to a video and an ABC news article about Chaser.
I don't know about you, but I definitely underestimated how smart dogs really are.
http://www.youtube.com/watch?v=QPgZ8KHLXag&list=UU2NjUImk-ITC_LhgsNvvADg&index=2&feature=plcp
http://abcnews.go.com/Technology/world-smartest-dog-nova-special-shows-border-collie/story?id=12875750

I've seen the intelligence of a dog first hand - my cousin can command his dog to go into the fridge and retrieve a wide variety of beverages (obviously no where near 1,000). I was also very shocked that an animal could distinguish the difference between "human" objects, considering dogs are usually considered unintelligent animals. I guess I never even thought to associate this intelligence in dogs to psychology, so you present an interesting perspective on the topic. It leaves you wondering what animals are truly capable of...