Chaser, the Border Collie who understands more than 1,000 nouns, has sparked some interesting discussions. I know Ranger understands some nouns and understands that some nouns can apply to different objects that share some characteristics. For example Ranger understands "book" to mean big or small, fat or thin, hardback or paperback. I can hold a book in one hand and a mug in the other and ask Ranger to touch the book and he will. He'll also correctly identify by touching the mug. We've played the name game for a few years now beginning with simply labeling an object. "Ranger, book" I'd say holding up a book for him to see. "Touch book" and when he puts his nose on the book he gets a treat. After about a month this got really boring. I'd take a book say "book. touch book." and reward the touch. Then I'd show him a mug (or whatever) and say "mug. touch mug." and reward that touch. After that I'd move the items around, sometimes add a third unidentified object and ask him to touch one of the objects we'd just named. By now Ranger can differentiate between a number of different objects and when we play the name game I only identify new objects.
Last night I decided to experiment. When Ranger hopped up on the couch next to me I took a mug in one hand and a book in the other and asked him to touch the mug. He did. I replaced the mug with a plate and asked him to touch the plate. He did even though to the best of my recollection I've never taught him the noun 'plate.' I stood the plate on end with the bottom facing Ranger and holding the plate on one side and a book on the other asked him to touch plate. He looked frantically between the two and began whining and barking his frustration. As soon as I returned the plate to a flat position he touched the plate. He's learned a general category of bookness but at this point only one configuration of the object is the plate. No general category of plateness.
Out of curiosity I held up two books one hardback and one paperback and asked him to touch book. Without hesitation he selected the one in my left hand. Wondering if perhaps he thinks paperbacks are more bookish I switched the books and now held the paperback in my right hand and the hardback in the left. Asked to touch book Ranger again selected the book in my left hand. No matter what kind of book I held on the left he always selected it when asked to touch book. Thinking he might be just targeting the left hand I picked the mug up in the left and the book in the right. He correctly chose the book.
In case you are wondering why so much emphasis on books. I am an avid reader with a very bad habit of putting my current read down and forgetting where. I started teaching book with the idea that someday we'll advance to the point where he can "find my book." Although I have to admit that picking out the current read from the huge number of books in my house will be some trick. I'm hoping he'll be able to distinguish the book with the largest amount of fresh me scent and identify the current read that way.
Ranger knows "Find Mom." "Go to Mom" and "Where's Mom" so I wondered if Mom was a noun in the same sense that book is a noun. I laid my hand on one side (he's used to touching my hand as that was the foundation of the touch command) and a book on the other and asked him to "touch Mom." Whining and frustrated barking ensued. Anything Mom apparently means leave where you are and go to where Mom is. In this context where he was already with me "touch Mom" was confusing. By the way we've played "Find book" at my mother-in-law's house and he understands to hunt for the book and signal when he has found it. We haven't played it at our house because with literally thousands of books around I'm afraid it would be too confusing.
And finally, while we were playing the name game he kept regularly signing "food." Correctly identifying the object named is rewarded with a treat.