Researchers at the University of Vienna in Austria have shown dogs possess the ability to classify complex colour photographs and place them into categories in the same manner as humans do.
The findings are based on tests involving computer-automated touch-screens.
The researchers showed four animal subjects landscape and dog photographs, expecting them to make a selection on a computer touch-screen.
In the training phase, the dogs were shown both the landscape and dog photographs simultaneously, and were rewarded with a food pellet if they selected the dog picture (positive stimulus). Thereafter, the dogs were made to participate in two tests.
Despite being shown completely different dog and landscape pictures in the first test, the dogs kept reliably selecting the dog photographs.
It was an indication that they could transfer their knowledge gained in the training phase to a new set of visual stimuli, even though they were seeing the particular pictures for the first time.
In the second test, the dogs were shown new dog pictures pasted onto the landscape pictures used in the training phase. The idea was to make them face contradictory information—a new positive stimulus in the form of new dogs' pictures, and a familiar negative stimulus in the form of the landscape.
When the dogs had to choose a picture from that of a new dog on the familiar landscape and that of a completely new landscape with no dog, they reliably selected the option with the dog.
The researchers said that the findings indicated that dogs were able to form a concept i.e. 'dog'.
However, the experiment did not make it clear whether the animals recognized the dog pictures as actual dogs.
Talking about the strength of their methodology, the study's authors said: "Using touch-screen computers with dogs opens up a whole world of possibilities on how to test the cognitive abilities of dogs by basically completely controlling any influence from the owner or experimenter."
They further said that their method could also be used to test a range of learning strategies, and that it had the potential to allow researchers to compare the cognitive abilities of different species using a single method.