Yes, dogs notice when you are upset. Studies show they react to crying differently than to other sounds, can match emotional faces to emotional voices, and can even detect changes in your scent when you are stressed. Whether they understand sadness the way a human friend does is less clear. The best current explanation is a mix of catching your emotion and having learned that going to you when you’re upset is the right thing to do.
Here is what the research actually shows, how dogs read your mood, and what to do when you’re having a hard time and your dog is watching.
What the research shows
Dogs respond to crying
One of the best-known studies was carried out by Deborah Custance and Jennifer Mayer at Goldsmiths, University of London, and published in Animal Cognition in 2012. Eighteen pet dogs watched their owner or a stranger pretend to cry, hum in an odd way or chat normally.
The dogs approached people more often when they were crying than when they were humming or talking. Observers who didn’t know which condition they were watching rated those approaches as submissive more often than playful or alert. When a stranger was the one crying, the dogs went to the stranger rather than to their owner and sniffed, nuzzled and licked them. That matters, because it suggests the dogs were responding to the person’s distress, not just looking for comfort from their own human.
The researchers were careful about what this means. They said the dogs’ behavior looked like empathic concern, but the simplest explanation is emotional contagion (catching another’s emotion) combined with past experience of being rewarded for approaching upset people.
Dogs can match faces and voices
A 2016 study led by Natalia Albuquerque, with researchers from the University of São Paulo and the University of Lincoln, showed 17 family dogs two faces side by side, either both human or both dog, one with a positive expression and one with a negative one, while playing a voice. The dogs looked longer at the face whose expression matched the emotional tone of the voice. That suggests they combine what they see and hear into a single read of someone’s emotional state. They were better at doing this with dogs than with humans, but they managed both.
An earlier study from the University of Veterinary Medicine Vienna, published in 2015, trained dogs to tell happy human faces from angry ones in photos, using only the eye half or only the mouth half of each face. The dogs could then sort faces they had never seen before, and even the half of the face they hadn’t been trained on.
One caveat: both studies tested positive versus negative emotions, such as happy versus angry. Sadness on its own has been studied less. So the evidence shows dogs can tell when your mood has turned negative, not that they can name it as sadness.
Dogs may smell stress
Dogs also have their noses. In a 2022 study in PLOS ONE, researchers at Queen’s University Belfast collected breath and sweat samples from volunteers before and after a stressful mental arithmetic task. Four trained dogs then picked out the stressed sample in 93.75% of trials.
This was a small lab study with trained dogs, and stress is not the same as sadness. But it shows that the body changes that come with distress produce a scent a dog can detect. Your dog may know something is off before you have said or done anything.
Your stress may rub off on your dog
Dogs don’t just notice our moods. They may share them. Researchers at Linköping University in Sweden measured cortisol, a stress hormone, in hair samples from 58 dogs and their owners. They found that long-term stress levels were synchronized: owners with higher stress tended to have dogs with higher stress. The owner’s personality had a strong effect on the dog’s stress, while the dog’s personality had little, which led the team to suggest that dogs mirror their owners’ stress. They also noted that more research is needed to confirm cause and effect.
Do dogs try to help?
A 2018 study published in the journal Learning and Behavior tested 34 dogs. Each owner sat behind a closed door that the dog could push open, and either cried or hummed. About as many dogs opened the door in both conditions, but dogs whose owner was crying opened it considerably faster. Dogs that didn’t open the door showed more signs of stress, which suggests some dogs may be too upset by a person’s distress to act on it.
Do dogs actually understand sadness?
This is where honesty matters. No study has shown that dogs understand sadness as a concept, or know why you are sad. What the evidence does support is this:
- Dogs notice when your behavior, voice, face and scent change.
- They respond to crying and distress differently than to other unusual behavior.
- Your emotional state can affect theirs, sometimes for months at a time.
- Many dogs have learned, through living with people, that coming close when someone is upset tends to go well.
Whether that adds up to empathy in the human sense is still debated. But from where you sit on the couch, the effect is real. Your dog has noticed, and it is responding to you.
How dogs pick up on your mood
Dogs read us through several channels at once:
- Sound: crying, sighing, a flat or shaky voice.
- Face: changes around the eyes and mouth.
- Body: slumped posture, slower movement, staying in one place.
- Smell: chemical changes in breath and sweat that come with stress.
- Routine: later mornings, skipped walks, meals at odd times. Dogs tend to notice when the day’s rhythm changes.
Signs your dog has noticed you’re upset
Every dog is different, but owners often describe:
- Coming over, leaning in, or resting a head on your lap
- Licking your hands or face
- Following you from room to room or lying closer than usual
- Bringing a toy
- Seeming unsettled themselves: pacing, yawning when not tired, licking their lips or hanging back
That last group is worth paying attention to. A dog that hangs back is not necessarily indifferent. Like some dogs in the 2018 door study, it may simply find your distress stressful and not know what to do.
Why some dogs don’t seem to react
If your dog doesn’t come to comfort you, it doesn’t mean it doesn’t care. Some dogs are more independent by nature. Some have never learned that approaching an upset person is welcome. Others may feel anxious themselves and keep their distance. Dogs that have had rough experiences with people may be cautious around raised emotion of any kind.
Dogs aren’t the only pets that respond to changes in us. Cats may also react to illness, anxiety and low moods in their own quieter way, as we cover in can cats sense when something is wrong. Pets also notice big life changes in their people, from a new job to a pregnancy.
What you can do when you’re sad and your dog is watching
- Accept the comfort. Letting your dog lie beside you or rest its head on your knee is fine, and many people find it steadying. There’s no need to hide your feelings from your dog.
- Keep the basics going. Regular walks, meals and play give your dog stability and give you a reason to get up and outside, even on a bad day.
- Watch for stress in your dog. During a long, hard stretch, look for changes in your dog’s appetite, sleep or behavior. Since stress can pass between owners and dogs, your dog may need extra exercise, play or quiet time too.
- Give your dog a way out. If your dog seems uneasy, make sure it has a calm spot to retreat to. Comforting you should be its choice, not a job.
- Don’t make your dog your only support. Dogs are wonderful company, but they can’t replace people. If sadness has settled in for weeks, or is getting in the way of daily life, talk to someone you trust or to your doctor.
The bottom line
Your dog almost certainly knows when you’re sad, in the sense that it notices the change in you and responds to it. Science can’t yet say whether your dog understands what you are feeling. But the head on your knee and the nose pushing under your hand are real responses to you, built on years of watching, listening to and living with you.