By placing dogs in an MRI scanner, researchers from Hungary found that the canine brain reacts to voices in the same way that the human brain does.

Emotionally charged sounds, such as crying or laughter, also prompted similar responses, perhaps explaining why dogs are attuned to human emotions.

Lead author Attila Andics, from the Hungarian Academy of Science's Eotvos Lorand University in Budapest, said: "We think dogs and humans have a very similar mechanism to process emotional information."

Eleven pet dogs took part in the study; training them took some time.

"We used positive reinforcement strategies - lots of praise," said Dr Andics.