British researchers have found that dogs can identify with sadness just as people can, whether they are familiar with a person or not.

A study conducted by Dr Deborah Custance and Jennifer Mayer, both of the Department of Psychology at the University of London, examined the responses of domestic dogs to human emotions.

The research involved exposing 18 pet dogs of various breeds and ages to four separate 20-second situations. The pet’s owner, or an unknown person, pretended to cry, hummed in a peculiar way or spoke casually.

Dr Custance observed that more dogs looked at, approached and touched the humans when they were crying as opposed to when they were humming, while no dogs responded to those talking.

The majority of dogs responded to the crying person submissively, consistent with the traits of empathy and comfort-offering.

"If the dogs' approaches during the crying condition were motivated by self-oriented comfort-seeking, they would be more likely to approach their usual source of comfort, their owner, rather than the stranger," Mayer said in a media release.

"No such preference was found. The dogs approached whoever was crying regardless of their identity. Thus they were responding to the person's emotion, not their own needs, which is suggestive of empathic-like comfort-offering behaviour."