The following information was found on Dog Intelligence Wikipedia.
Dogs’ intelligence or dogs’ cognition is their ability to learn, think, and solve problems. They are capable to learn by simple reinforcement and by watching humans and other dogs. Puppies learn very fast by following more experienced dogs. In addition, dogs have the ability to learn names of objects. In a study, Betsy, a black and white longhaired Border Collie (this breed is considered to be the most intelligent on Earth), learned 340 words and could connect objects with a photo of the objects without having seen neither before.
Several studies have shown that dogs have very complex emotions. They could feel jealousy, guilt, love, etc. In another study, which used a Siberian husky, researchers found that when the dog had the habit of shredding newspapers of his owner and he returned home, the dog behaved guilty.
Also, an important concept that applies to dogs is “object permanence”. They understand that objects exist although those are not in their field of view. The same ability is developed in human babies between 4-7 months. This skill is also not present at birth in dogs, but is later developed (around week 8).