Washington: When a dog learns to associate a word with an object, it makes the association in a completely different way to humans, according to new research.
When toddlers pick up language, they learn by associating words with the shapes of objects.
For example, toddlers who learn what a ``ball`` is and are then presented other objects with similar shapes, sizes or textures will identify a similarly-shaped object as ``ball``, rather than one of the same size or texture.
Earlier research with dogs has shown that they can learn to associate words with categories of objects (such as ``toy``), but whether their learning process was the same as that of humans was unknown.
In this new study, the scientists presented Gable, a five year old Border Collie, with similar choices to see if this ``shape bias`` exists in dogs.
They found that after a brief training period, Gable learned to associate the name of an object with its size, identifying other objects of similar size by the same name.
After a longer period of exposure to both a name and an object, the dog learned to associate a word to other objects of similar textures, but not to objects of similar shape.
The difference in the thought process between dogs and humans may come down to how evolutionary history has shaped our sense of perceiving shapes, sizes and textures, said Dr Emile van der Zee, who led the research.
“Though your dog understands the command “Fetch the ball”, he may think of the object in a very different way than you do when he hears it,” Dr van der Zee said.
“Where shape matters for us, size or texture matters more for your dog. ``This study shows for the first time that there is a qualitative difference in word comprehension in the dog compared to word comprehension in humans,” he added.
The study was recently published in the open access journal PLOS ONE.