Easy to train dog breeds

I was clicking around on the Animal Planet Dog Breed guide - awesome page, by the way. They have a section for Easy-to-Train dog breeds.

I'm not surprised to see the Border Collie high on the list. The German Shepherd is also a given.

In alphabetic order, the list is:
Australian Cattle Dog
Australian Shepherd
Border Collie
Cardigan Welsh Corgi
Doberman Pinscher
German Shepherd
Golden Retriever
Labrador Retriever
Papillon
Poodle
Rottweiler
Shetland Sheepdog

I understand how the working breeds learn easily, but the list made me curious. I definitely need to learn more about the Papillon!