Seems like our two species, human and canine, have gotten really good at reading each other’s faces. Which shouldn’t be a surprise— after all, we’ve spent a long time together, anywhere from 15,000 to more than 100,000 years, so we have a lot of practice in mastering this important social indicator.
Researchers have looked at how dogs distinguish between our positive and negative expressions, and a recent study also investigated how well we’re able to get a read from dog faces. In the current human-looking-at-dog investigation, participants (some dog people, some not) were asked to evaluate dogs’ emotional states based on their facial expressions. Options ranged from sadness, fear, disgust and anger/aggression to happiness and surprise; participants were also asked to rate the degree to which these emotions were expressed. Results showed that humans, even those who were the least empathic, were pretty good at this (the more empathic observers got the highest grades). We seem to be naturals at it. As Charles Darwin observed, our facial expressions are similar to those of dogs, so if we can understand human frowns and smiles, we can similarly deduce how our closest nonhuman companions are feeling.
In an earlier study,* researchers wanted to see how dogs perceived both human and canine emotional states. Photos were paired with auditory cues: dog faces/dog vocalizations, unfamiliar human faces/audio in Portuguese (to prevent dogs from recognizing specific words). In this test, dogs scored 67 percent, meaning that they looked longer at facial expressions that matched the audio cues. The researchers concluded that dogs can discriminate “between positive and negative emotions from both humans and dogs,” and therefore demonstrated that these adaptive benefits enabled them “to evaluate the social intentions motivation of others.” An intriguing first take on another example of interspecies communication and further evidence of our very long term relationship with dogs.
Lots of us talk to our dogs as we do to children, pitching our voices higher and speaking more slowly. Some only speak this way to puppies, others do it with adult dogs as well. But do tone and cadence make a difference to a dog? A group of researchers asked this question, and the results of their study showed that puppies do indeed respond better to the higher pitched, “Who’s my baby” approach by becoming more attentive and responsive. Adult dogs didn’t seem to have a preference. (I know, though, that my dogs just like to hear me talk to them, no matter how I do it.)
This brings up another recent study, in which researchers in the UK explored the effects a variety of sounds had on canine behavior in a shelter. As a control, they used regular kennel sounds, to which they compared the effects of classical, pop, psychoacoustically designed canine music and an audiobook. Not surprisingly, they found that pop music provoked the highest rate of barking. But it wasn’t classical or specially designed canine music that calmed dogs down the most. First place went to the audiobook—dogs spent more time resting and less time displaying vigilant behaviors, such as repetitive pacing. The researchers concluded that their findings show a strong potential for auditory enrichment that can improve the welfare of shelter dogs.
*Albuquerque, Natalia, et al. Dogs recognize dog and human emotions. Biology Letters 12:1. DOI: 10.1098/rsbl.2015.0883