Can dogs ‘catch’ our emotions?

How many times have you heard someone say, “My dog can tell when I’m sad,” or “When I’m worried, my dog gets worried too”? In years past, people would have called this anthropomorphizing: mistakenly attributing human emotions or traits to animals.

Today, however, science is saying something different. Numerous studies over the past six years show that we send behavioral and chemical signals to our dogs that not only allow them to “read” our emotions — fear, happiness, sadness, anger — but to also “catch” these feelings from us.

We now know that the phenomenon known as emotional contagion — when one person “catches” someone else’s emotional state the way they would a contagious disease — also exists between humans and their dogs. Because dogs are so highly social, they are easily influenced by — some say infected by — our emotions, whether positive or negative. This ability of dogs to understand and internalize human emotions has a great deal to do with the length and depth of the bond between the person and the dog: the more time we spend interacting with our dogs, the greater the likelihood that they will be able to connect with and capture our feelings.

One of the human chemical signals dogs pick up on when we interact with them, pet them or even just look into their eyes is the hormone oxytocin, the “feel good” or “love” hormone.

Oxytocin also acts to lessen anxiety, which in turn leads to further emotional bonding. Interestingly, dogs also experience a surge of oxytocin when they’re interacting with us, creating a kind of positive feedback loop.

Scent also plays a role in our dog’s ability to catch our emotions. As we know, a dog’s sense of smell is profoundly better than our own, and that extends to scents we humans simply can’t smell at all. Scientists and researchers suspect that it’s through human odors that medical-alert dogs can sense an oncoming medical crisis — for instance, signaling someone with epilepsy about the onset of a seizure, or warning a person with insulin-dependent diabetes of a dangerously low or high blood sugar level.

But it’s not just medical-alert dogs that can sense our emotions through scent.

Recent studies have shown that even pet dogs can smell changes in human breath and sweat, and can pick up on chemical odors their humans emit when feeling stressed. These kinds of scent cues help our dogs read and respond to our emotional states.

Dogs also use other signals to help them understand and respond to human emotions, including our facial expressions and tone of voice. Dogs have a remarkable ability to read the facial expressions of human beings, similar to the way people interpret the facial expressions of other people. Studies show that their gaze shifts and heart rate increases or decreases depending upon whether they’re shown human faces with expressions of anger, fear, happiness, sadness, surprise or disgust.

Dogs also understand the emotion behind the human voice, depending on whether it expresses positive or negative emotions. The dog doesn’t so much respond to the word itself, just the tone of voice: they can even distinguish between positive and negative emotions when someone uses nonsense words or nonverbal sounds like “uhh” or “umm.”

And when dogs hear human expressions of distress like crying, or positive sounds like laughing, they respond differently than they do to unemotional communication or non-human sounds.

While sharing a home and a life add to the quality of our connection with our dogs, sharing each other’s feelings helps us understand each other better and strengthens the bond between us — a bond that can last for a lifetime.

Joan Merriam lives in Northern California with her Maine coon cat Indy, the infinite spirit of her beloved golden retriever Joey, and the abiding presence of her dog Casey, in whose memory this column is named. You can reach Joan at joan@joanmerriam.com.