These dogs usually understand new commands after less than 5 repetitions by the facts in the book The Intelligence of Dogs by Stanley Coren, a professor of psychology at the University of British Columbia in Vancouver. Doberman Pinscher, Border Collie, Rottweiler, German Shepherd, Golden Retriever, Shetland Sheepdog, Labrador Retriever, Papillion, Poodle, Australian Cattle Dog.