The Genius of Dogs by Brian Hare and Vanessa Woods is a great book to look at.
Brian founded the Duke (as in University) Canine Cognition Center where they study dogs to help determine their true intelligence and how they learn. This has been a fast growing area as scientists and behavioral studies experts around the globe have been finding out just how smart “man’s best friend” really is.
If you are truly interested, you might even check out their website http://www.dognition.com that is an offshoot of their university work. There are some sample activities you can try for free. Additionally for a fee, you can join the studies and test your own dog with tests created by the Center. Your results will be added to the others reported by “citizen scientists” and reviewed by the center. It is not meant to signify “my dog is smarter than yours.” Rather, it provides insights as to how your dog learns and how you might better communicate with your dog.