New research suggests that dogs are able to recognize human emotions, giving a new, deeper relevance to man's best friend, according to Science Daily.

Researchers from the University of Lincoln in the U.K. and the University of Sao Paulo in Brazil have demonstrated that dogs form an abstract understanding of emotions using their various senses.

"Using a cross-modal preferential looking paradigm, we presented dogs with either human or dog faces with different emotional valences (happy/playful versus angry/aggressive) paired with a single vocalization from the same individual with either a positive or negative valence or Brownian noise," the study stated. 

In the experiment, dogs stared longer at the images that had a correctly corresponding vocalization. 

The dogs in the experiment differ from previous experiments in that they were able to distinguish emotion without training or using only facial cues.

"Previous studies have indicated that dogs can differentiate between human emotions from cues such as facial expressions, but this is not the same as emotional recognition," said researcher Kun Guo with the University of Lincoln. "Our study shows that dogs have the ability to integrate two different sources of sensory information into a coherent perception of emotion in both humans and dogs."

To categorize emotional states was a cognitive ability once believed to only be present in primates, not to mention the ability to process emotional states in other species, which was believed to not exist in the animal kingdom. 

The research was published in the Jan. 13 issue of Biology Letters.