How Dogs Recognize Human Emotions
Researchers at the University of Lincoln in the U.K. say that dogs actually rely on multiple sensory information to recognize human emotions--an ability that so far has been identified only in humans and primates.
Previous research has suggested that a dog's ability to differentiate between human emotions was "associate behavior" -- it linked certain emotional states to facial expressions or other cues it has learned. But these findings challenge that belief.
For the study, published in the journal Biology Letters, the team showed 17 domestic dogs pictures of both humans and other dogs displaying positive (happy or playful) or negative (angry or aggressive) emotional expressions. Alongside the picture presentation, the researchers also played positive or negative audio clips (voices or barks) from unfamiliar human and canine subjects.
The scientists determined that when the dogs were shown a picture that matched the emotional state of an audio clip -- for example, if an angry voice matched an angry facial expression -- they spent much longer looking at it. This was the case when they were exposed to both human and canine pictures and audio clips.
That, the study authors concluded, suggests that dogs have the ability to integrate two different sources of sensory information to read the emotions of humans or other dogs--an ability they said requires a capability to categorize different emotional states.
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