The next time you see your dog and wonder whether he or she can tell how many treats you are holding in your hand—be assured that they can. According to a new study, dogs spontaneously process basic numerical quantities using a particular part of their brains that is very similar to the neural region in the human brain that responds to numbers.
The study by researchers from Emory University suggests that despite mammals evolving into different forms, a common neural mechanism is deeply conserved between them. "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, senior author of the study.
Studying the brain's response to numbers in dogs
Eleven dogs from different breeds were subjected to functional magnetic resonance imaging (fMRI) scanning for the study. They were trained to enter the fMRI and stay, without being sedated or restrained. Their brains were scanned as they looked at the number of dots flashing on a screen. It was found that the parietotemporal cortex of the dogs responded to the variation in the number of dots.
As the total area of the dots was held constant, the scientists were able to ascertain that dogs were responding to the number of dots and not the size. Of the eleven dogs, there was higher activation of the parietotemporal cortex in eight of them, when the ratio between alternating arrangements of dots was more dissimilar than when it was constant.
"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, first author of the study, in a statement.
The basic response of the brain to numerical information is known as Numerosity. Canine response in the experiment to the changing numerical value was driven by this. It is important to note dogs and human beings are separated by 80 million years of evolution. "Our results provide some of the strongest evidence yet that numerosity is a shared neural mechanism that goes back at least that far," Berns pointed out.
However, deriving from the prefrontal cortex, humans have the ability to build on basic numerosity for solving complex mathematics, which is unlike dogs or other animals.
Aulet pointed out that human ability to solve complex mathematical problems is due to our shared trait of numerosity with our fellow mammalians. "I'm interested in learning how we evolved that higher math ability and how these skills develop over time in individuals, starting with basic numerosity in infancy," she added.
Practical applications in the future?
"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 Stella Lourenco, co-author of the study.
She suggests that the insights obtained from such studies may see practical applications. From treating brain abnormalities to perfecting artificial intelligence systems, understanding the neural mechanisms of mammals can help in providing solutions to an array of problems.