If you’ve ever felt like your dog knows exactly what you’re thinking, you might just be right.
That’s according a new study, which has revealed that dogs’ brains sync with ours when they gaze into our eyes.
Scientists from the Chinese Academy of Sciences found that neurons in parts of the brain associated with attention synchronised more strongly as pairs of dogs and humans became more familiar.
However, dogs with a gene that causes autism-like symptoms showed much lower synchronisation.
It has long been known that humans brains sync up as we interact but this marks the first time that brain synchrony has ever been observed across species.
Researchers have found that the brains of humans and dogs synchronise as they gaze into each other’s eyes (stock image)
Whenever humans interact in social situations, the patterns of activity in our brains and bodies begin to fall into synchronised patterns.
Subconsciously, our heart rates, breathing, and the activation of neurons in the brain become the same as those of the people around us.
In their paper, published in Advanced Science, the researchers explain: ‘During social interactions, interacting individuals are not isolated, but are embedded in a multibrain system.’
Scientists have recently observed that mice, bats, and monkeys also experience a similar kind of synchronisation when engaging with members of their own species.
Scientists monitored the brains of humans and dogs as they either remained separate, stayed in the same room, or interacted. As these graphs show, the levels of synchronisation were much higher while the pair were interacting (bottom graph)
But, until now, scientists have never observed brain synchronisation between members of two different species.
To try to understand if this was possible, the researchers fitted pairs of humans and dogs with EEG monitors to record their levels of brain activity.
Dogs were chosen as the experimental animal of choice since research has proven that dogs have a remarkably deep connection with humans.
Previously unfamiliar pairs had their brain activity recorded while in separate rooms, in the same room but not interacting, and while petting and looking into each other’s eyes.
Over five days, the level of synchronisation increased (illustrated in the bottom graphs). In the top graphic, the brighter colours show regions of the brain which were more synchronised as the pair became more familiar
The researchers found that the pairs’ brains became much more synchronised while they were engaging than when they were just in the same room.
The researchers write: ‘We demonstrated for the first time that directed interbrain neural coupling occurs between humans and dogs, particularly in the frontal and parietal regions, both of which are associated with joint attention.’
The level of synchronisation also dramatically increased over five days of testing as the pairs became more familiar.
In a second experiment, the participants were either asked to pet the dog without making eye contact or just making eye contact without touching.
Both forms of interaction raised the level of brain synchronisation, but eye gazing was associated with more activity in the brain’s frontal region while petting produced activation in the parietal region.
In a second experiment, the humans either looked at or petted the dog. This revealed that physical petting and eye-gazing cause different parts of the brain to synchronise
By analysing the data, the researchers found that it was humans who led the interaction. These graphs show the amount of data which ‘flowed’ from the human to the dog (in blue) compared to the amount of data flowing from the dog to the human (red)
Importantly, the synchronisation created by touch and eye gazing together was more than the sum of these interactions separately.
This suggests that interactions which use more than one form of communication create a much stronger connection at the neural level.
The researchers also used these findings to deepen our understanding of autism spectrum disorders (ASD).
Using the CRISPR gene editing technique, the researchers created dogs with a mutation on the SHANK3 gene – one of the most common risk factors for ASD.
Dogs with this mutation showed clear autism-like behaviours and displayed significantly reduced brain synchrony when interacting with humans.
The researchers found that dogs with autism-like symptoms did not display brain synchronisation – a condition which could be cured with a single dose of LSD (stock image)
Dogs with a genetic mutation linked with autism showed much lower levels of brain synchrony. However, 24 hours after receiving a dose of LSD their levels of neural connection became normal
Co-author Dr Yong Zhang, of the Chinese Academy of Sciences, says: ‘Disrupted inter-brain synchronization might be used as a biomarker for autism.’
However, in an unusual development, the researchers also found that a single dose of the psychedelic LSD was able to almost completely reverse these effects.
The dogs were given a dose of 7.5 micrograms of LSD per kilogram of weight – the equivalent of a 600 microgram dose for an 80kg human.
For reference, a 2021 study found that a 200 microgram dose in humans was sufficient to produce ‘ego dissolution’ and ‘oceanic boundlessness’.
24 hours after administering the drug the researchers performed the test again and found that synchronisation significantly increased in the parietal and frontal regions.
The researchers say these findings could pave the way for treating or managing some of the disruptive symptoms of autism spectrum disorders in humans.
Dr Zhang says: ‘LSD or its derivatives might ameliorate the social symptoms of autism.’
