From wagging tails to expressive eyebrows, dogs already have plenty of ways of making their emotions known to humans.
But scientists have found another surprising way they could be trying to tell you something important – by blinking.
A study has discovered that dogs use blinking as a ‘subtle affiliative signal’ when they look at people they are close to.
That means your pet’s fluttering lashes could be them trying to communicate friendliness or build a closer social bond with you.
In the study, scientists from the University of Parma, Italy, discovered that dogs started blinking faster when they saw a human blinking, compared with when they saw footage of someone staring.
However, the effect only kicked in if the person in the video was their owner.
Lead author Dr Chiara Canori told the Daily Mail: ‘I believe that it suggests that dog-human communication may be more subtle and responsive to social relationships than we actually recognise.
‘There may be a much richer layer of communication in these small, overlooked changes in behaviour, and learning to recognise and acknowledge them could help us better understand our dogs.’
If your dog blinks at you, researchers say it could be a ‘subtle affiliative signal’, meaning it is meant to communicate friendliness or strengthen your social bond
Researchers found that dogs started blinking faster when they saw a human blinking, but only if it was their owner. The effect was also more pronounced if their owner was a woman
‘At its most basic level, blinking is a physiological behaviour that protects the eye and maintains the ocular surface,’ says Dr Canori. ‘What is interesting is the possibility that this very old, automatic behaviour may also have acquired some social relevance.’
In their study, the researchers showed 35 dogs videos in which humans were either blinking or staring straight ahead with their eyes open.
When the dogs saw videos of people staring, their blink rate remained unchanged.
However, when they saw footage of their owners blinking, their blink rate started to increase.
Unusually, this effect was strongest when the owner was a woman.
The authors suggest that this effect could reflect the greater attention and social engagement a dog has with their owner compared to a total stranger.
The authors caution that they can’t yet determine whether these blinks have any specific meaning beyond social engagement.
Scientists showed dogs videos of people either blinking or staring straight ahead and recorded how their own blink rate changed
Dr Canori says: ‘Our study does not show that a dog is deliberately “saying something” every time it blinks; rather, it suggests that this apparently simple and automatic behaviour can be influenced by the social context.’
However, that observation does reveal a glimpse into the fascinating complexity of the relationship between dogs and humans.
Previous studies have shown that dogs are able to tell the difference between humans’ happiness, anger, fear and sadness from facial expressions alone.
Researchers discovered that seeing a human smiling lights up a unique region of a dog’s brain, which doesn’t react to negative facial expressions.
Likewise, research has even shown that dogs have the unique ability to smell human stress in our sweat and on our breath.
Blinking has been found to have some social relevance in other animals also. Cats, for example, will return their owners’ slow blinks as a sign of affection, and are more likely to approach people who have blinked at them first.
‘The fact that dogs modulated their blinking depending on whether the human was their owner suggests that their responses are not simply triggered by seeing a human face or movement, but may be influenced by the social relevance of that particular person,’ Dr Canori explains.
‘So the connection between dogs and humans is built not only through obvious signals such as vocalisations or gestures, but also through these much more subtle, dynamic behavioural cues.’
