An instinctive process
Better yet, they don't need to be trained to do so which means this process is instinctive. The novel research used functional magnetic resonance imaging (fMRI) to scan dogs' brains.
The dogs were made to view a different number of dots as they flashed on a screen. The total area of the dots stayed the same in order to ensure it was the number of the dots, not the size that the dogs were reacting to.
The scans revealed that the dogs' parietotemporal cortex responded to the number of the dots. This is the same brain region that responds to numbers in humans.
"Our work not only shows that dogs use a similar part of their brain to process numbers of objects as humans do -- it shows that they don't need to be trained to do it," said Gregory Berns, Emory professor of psychology and senior author of the study.
"Understanding neural mechanisms -- both in humans and across species -- gives us insights into both how our brains evolved over time and how they function now," said co-author Stella Lourenco, an associate professor of psychology at Emory.
No advanced training
Eleven dogs were involved in the study none of which received advance training in numerosity. Out of the 11 dogs, eight showed greater activation in the parietotemporal cortex during the experiment.
"We went right to the source, observing the dogs' brains, to get a direct understanding of what their neurons were doing when the dogs viewed varying quantities of dots," said Lauren Aulet, a PhD candidate in Lourenco's lab and first author of the study.
"That allowed us to bypass the weaknesses of previous behavioral studies of dogs and some other species."
The study is published in Biology Letters.