Like humans, dogs have the capacity to link words to mental images or ideas in their minds, researchers have recently found.

Researchers in Hungary and Norway made the discovery while researching brain activity in dogs. 

They had dog owners show their pets toys while playing recordings referencing each toy. Sometimes the toys they held matched the words the dogs heard. Other times, the toys were different from the words spoken.

The dogs’ brains responded differently when the owner said a toy name but held up a different object. 

“In the case of the different toys, the response wave is bigger than the response wave for the matching object,” said Marianna Boros, a co-lead author on the study and postdoctoral researcher at Eötvös Loránd University’s Neuroethology of Communication Lab in Hungary.

“This is something that has been also observed in humans. … This is the first time we were able to demonstrate something similar in a nonhuman mammal,” she said.

She added that the team invited dogs whose owners said the animals know at least three object names. The study’s sample also included a dog who knew over 230 object names.

“If a dog will learn an object name … it links a word to a representation in its mind and not just contextually associate and try to figure out what is expected from them,” said co-lead author Lilla Magyari, a researcher at Eötvös Loránd University’s Neuroethology of Communication Lab in Hungary and an associate professor at Stavanger University in Norway.

The findings are set to be published in the peer-reviewed journal Current Biology.

Dogs and their understanding of the human language

The researchers at the Neuroethology of Communication Lab took on the study because they are interested in how the brains of different mammal species process speech and voices, as well as the social cognition of different mammals.

Dogs are a “very special” species because they've lived in close proximity to humans for at least 18,000 to 30,000 years, said Boros. 

“They not only live around humans but they live immersed in the human socio-linguistic environment,” she said. “They are exposed to speech on an everyday basis. They have toys. They live in the human physical environment as well. They are part of our family.”

Dogs are good at responding to instruction words such as “sit,” or “come” and while some dogs have learned hundreds of object names, others struggle to do so, Boros said. The research team wanted to find out why that is.

The team wanted to look into how much dogs understand the human language.

“We want to know whether animals can have certain language skills which are present in humans,” said co-lead author Magyari. 

How researchers, dogs and the humans who love them made this happen

The researchers looked into canine cognition using methods previously used on infants. 

Owners brought their dogs to the lab, along with toys they normally play with. Researchers recorded the dog owners referring to different toys.

The dogs were separated from their owners and sat across from them and peered at the owners through a window, almost like a television with a green screen.

Researchers first played the pre-recorded messages from the dog owners, then the dog owners held up toys for the dogs to see in live action. Sometimes they tricked the dog by playing one message but showing the dog a different toy.

The researchers said they can infer from the dogs’ brain activity that the canines were expecting to see the object named by the owner. 

When that didn’t happen, “it violated that expectation” resulting in different brain activity, Magyari said. 

Limitations of the study

Magyari said the study has its limitations. First, this is just one study and researchers need to conduct more.  

The researchers also don’t know how this skill developed in dogs. It could be domestication or evolution. 

The researchers are happy the experiment was a success because now, researchers can do different versions of this study to find out more, she said.

“I think there are still many other open questions,” Magyari said.

Saleen Martin is a reporter on USA TODAY's NOW team. She is from Norfolk, Virginia – the 757. Follow her on Twitter at@SaleenMartin or email her at[email protected].