However, it is questionable whether the cognitive evolution of humans and animals may be called "independent," as the cognitive capacities of dogs have inevitably been shaped by millennia of contact with humans.[6][7] As a result of this physical and social evolution, dogs have acquired an ability to cues,[8][9][10] fast mapping of novel words,[11] cognitive bias[12] and the possibility that dogs have other emotions.[13]
Other studies suggest that domestic dogs may have lost some of their original cognitive abilities once they joined humans. For example, one study showed compelling evidence that Dingos (Canis dingo) can outperform domestic dogs in non-social problem-solving experiments. Another study indicated that after undergoing training to solve a simple manipulation task, dogs that are faced with an insoluble version of the same problem look at the human, while socialized wolves do not. Thus, modern domestic dogs seem to use humans to solve their problems for them.[4][14]
Finally, it should be noted that most modern research on dog cognition has focused on pet dogs living in human homes in developed countries. This is only a small fraction of the dog population, and dogs from other populations may show different cognitive behaviors.[15] Breed differences among dogs indicate that genetic factors play an important role in dog intelligence, and such differences must be also taken into account in interpreting studies of cognitive capacity