Reading the emotions of others is crucial if we want to understand social interactions and intentions. Every species needs to be able to “read” members of their own species to understand how to behave in different situations, and we use both obvious and subtle visual and auditory cues to be understood. For some species such as companion animals, recognizing and reading the emotional states of multiple species — such as other dogs as well as humans — can be just as important. While some research with companion dogs has shown “cross-modal capacity in dogs relating to the perception of specific activities or individual features … it remains unclear whether this ability extends to the processing of emotional cues.”

Researchers already know that dogs can discriminate human facial expressions and emotional sounds, but what they don’t know is whether it can be scientifically shown that “dogs can extract and integrate emotional information from visual (facial) and auditory (vocal) inputs.” To test this, researchers worked with 17 healthy, socialized, adult family dogs of various breeds and presented them simultaneously with two different sources of emotional information. These included pairs of “grey-scale gamma-corrected human or dog face images from the same individual but depicting different expressions (happy/playful versus angry/aggressive),” which were shown on two screens at the same time as a sound was played. The sound was either “a single vocalization (dog barks or human voice in an unfamiliar language) of positive or negative valence from the same individual, or a neutral sound (Brownian noise).”

The researchers found that dogs showed a “clear preference for ‘congruent face'” (as in, the face that matched the sound) in 67% of the trials and that the dogs “looked significantly longer at the face whose expression matched the valence of vocalization.” They note that these results suggest that “domestic dogs can obtain dog and human emotional information from both auditory and visual inputs, and integrate them into a coherent perception of emotion.” For companion animal advocates, and even just people who live with companion dogs, the results may not be surprising. Nonetheless, they are a good reminder that dogs have keen senses, and can pick up on all kinds of cues from us, whether or not we even realize we are sending such cues.