Any discussion of intelligence, dogs, and humans, should include something about neoteny.
Neoteny is a process in Evolution in which infantile traits are expanded. Dogs and Humans are both neotenous, though humans are much more so.
What this means is that both dogs and humans have a greater plasticity of mind than their forebears, and humans especially can keep learning things throughout their lives. Other animals may start out with superior instincts, sort of plug-and-play, but humans (and dogs to a much lesser extent) are able to improve their knowledge for years and years. You might say most animals have more ROM, and humans more writable and re-writable memory.
For an interesting article on neoteny, see:
http://www.davidbrin...nyarticle1.html
Baldur