How dogs know what we're feeling
If you're someone who prefers to keep your emotional state secret from everyone, then steer clear of your dog! A growing body of scientific research shows that dogs are just too skilled at sensing and/or interpreting how we're feeling to be duped.
In recent times, research has shown that:
Dogs can recognize emotions in people's facial expressions.
They're able to distinguish emotional facial expressions from neutral expressions, and they can tell happy faces from angry ones - just from photos of faces.
Dogs can sniff out human emotions by smell alone.
Researchers collected sweat samples from human volunteers who had watched videos designed to cause them fear or happiness, and then presented the samples to the dogs to sniff (lucky them!). They then monitored the dogs' behaviours and heart rates and found that dogs exposed to human fear smells showed more signs of stress than those exposed to happy or neutral smells. The 'fear sweat' sniffers also had higher heart rates, sought more reassurance from their owners and made less social contact with strangers.
Dogs can distinguish different emotions in human voices alone.
They even 'process' the voices differently in their brains depending on whether they involve positive or negative emotions. Previous studies have shown that generally speaking, non-verbal human voices associated with positive emotions are processed in the left side of the dog's brain while voices with negative emotions are processed in the right side of the brain.It's nothing to do with the words used, just the sound of the voice - so the dogs in the study weren't responding as a result of picking up on learnt negative or positive words. Interestingly, there was a clearer difference in brain processing when the negative emotion in the voice was fear or sadness - rather than anger - or when the positive emotion was happiness.
Another study also suggests that a dog's brain breaks up speech into two parts: The emotional cues and the meaning of the words.
They then process these two components on opposite sides of the brain: emotional cues on the right, meaning of words (once dogs have 'learnt' what a word is associated with) on the left.That's quite similar to how we humans process speech. We also break up speech into several parts, such as the meaning of the words, clues about the speaker and emotional cues. This has implications for dog training, showing that it's not just which words you use that'll have an impact on how your dog responds, it's also how you're feeling when you say them.
Influence our emotions
And there's more. Our canine friends are also very good at knowing when they have our attention, and using it to best effect to influence our emotions.
Research has found that dogs' faces are most expressive when they know people are looking at them. Although it's not yet clear exactly how dogs visually signal us and how we respond, there's certainly evidence that we're susceptible to these signals. One study found that when dogs were being watched they often raised their eyebrows in a particular way. This eyebrow raise is known to give dogs in rescue centres a better chance of being rehomed. It may make the dogs' eyes look 'sad' or infant-like, creating an empathetic response from us.
It's not clear what role, if any, the domestication of dogs played in the development of these behaviours but we could speculate that it helped them get what they wanted/needed! There's even some evidence to suggest that dogs may actually mimic human facial expressions.
Studies have already shown what many owners of sociable dogs will have observed i.e. that dogs will mimic each others' body language (e.g. play bowing), especially if they're closely bonded. Some researchers now believe that the same behaviour can happen between a dog and their owner, with the dog effectively 'smiling' when the owner grins, for example.
This mimicry between animals tends to be seen as one of the factors that indicates the existence of empathy. So if our dogs really do copy our facial expressions, it may indicate that they're feeling something akin to empathy with our feelings.
Sharing our emotions
So, the next time you're laughing or crying, smiling or frowning, or just feeling happy or afraid, remember that the sounds, facial expressions and even the smells (!) you produce are meaningful to your dogs, and that their brains react accordingly.
They may, therefore, quite literally be 'sharing' our emotions so we really need to think about what impact that can have on them and how it can affect their behaviour. And we also need to remember that they can make it happen the other way round.
As all dog owners know, those 'puppy dog eyes' and raised eyebrows can be very effective! The human/canine relationship is a very special one.