Study suggests shared neural-mechanism across evolution
A study at Emory University has shown that dogs are able to spontaneously process basic numerical quantities, using a specific part of their brain that closely resembles number-responsive neural regions in humans.
The research used functional magnetic resonance imaging (fMRI) to scan the brains of 11 different dog breeds as they viewed varying numbers of dots flashed on a screen. Eight of the 11 dogs showed greater activation in the parietotemporal cortex when the ratio between alternating dot arrays differed compared to when the numerical values were constant.
Dr Gregory Berns, senior author of the study and professor of psychology at Emory University said: “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.”
“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,” added co-author Stella Lourenco, associate professor of psychology at Emory.
The ability to quickly estimate the number of objects in a scene, known as numerosity, does not rely on symbolic thought or training and seems to exist in species throughout the animal kingdom. However, until now, much of the research into this ability in non-humans has involved intensive training of the subjects.
The Dog Project, founded by Mr Berns, was the first to train dogs to voluntarily enter an fMRI scanner and stay still during the scan without sedation or restraint. This knowledge was able to be utilised in this most recent study. The dogs involved also received no advance training in numerosity.
First author of the study Lauren Autlet said: ”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. That allowed us to bypass the weaknesses of previous behavioral studies of dogs and some other species."
“Humans and dogs are separated by 80 million years of evolution,” Mr Berns adds, "Our results provide some of the strongest evidence yet that numerosity is a shared neural mechanism that goes back at least that far.”