The idea dogs are exceptionally bright really is a myth, according to new research.
They are no more intelligent than a host of other animals including lions, wolves, pigs, horses – and even the humble goat, suggests the study.
And scientists say that a reputation for being brainy does dogs more harm than good – because it makes us expect “too much of them”.
In the first study of its kind, researchers found that people that imagine man’s best friend is mentally superior to cats and other domesticated creatures could be barking up the wrong tree.
They also failed to stand out among social ‘single’ predators that don’t hunt in packs like dolphins or carnivores like hyenas.
Man’s best friend is a member of all three groups. By pooling data from previous analyses the English team did not shine in tests involving 12 other species.
Dr Britta Osthaus, of Canterbury Christ Church University in Kent, said: “Taking all three groups – domestic animals, social hunters and carnivorans – into account, dog cognition does not look exceptional.”
The cognitive abilities of dogs were at least matched by others in each of the three groups, reports learning and behavior.
Dr Osthaus said: “We are doing dogs no favour by expecting too much of them.
“Dogs are dogs – and we need to take their needs and true abilities into account when considering how we treat them.”
The study examined more than 300 papers on the intelligence of dogs and other animals and identified several cases of “over interpretation” in favour of the former.
Lead author Professor Stephen Lea, of Exeter University, suggested all too often skewed studies involved the tail wagging the dog:
“During our work it seemed to us many studies in dog cognition research set out to ‘prove’ how clever dogs are.
“They are often compared to chimpanzees and whenever dogs ‘win’ this gets added to their reputation as something exceptional.
“Yet in each and every case we found other valid comparison species that do at least as well as dogs do in those tasks.”
The review – which also included raccoons, chimpanzees and pigeons – focussed on sensory cognition, physical cognition, spatial cognition, social cognition and self-awareness.
It sought to place these skills “in context” by comparing those of dogs with other domestic animals, carnivores and social hunters that has not been done before.
Prof Lea said: “A principled understanding of canine cognition should therefore involve comparing dogs’ cognition with that of other carnivorans, other social hunters and other domestic animals.
“This paper contrasts dog cognition with what is known about cognition in species that fit into these three categories – with a particular emphasis on wolves, cats, spotted hyenas, chimpanzees, dolphins, horses and pigeons.
“Although the comparisons are incomplete, because of the limited range of studies of some of the other relevant species, we conclude that dog cognition is influenced by the membership of all three of these groups, and taking all three groups into account, dog cognition does not look exceptional.”
There was no evidence associative learning – anticipating an event by the occurrence of another – is in any way unusual in dogs.
Dogs’ smelling senses are excellent, but similar abilities have been found in some other carnivores and domestic animals.
Prof Lea said: “Dogs’ sensory cognition seems to be similar to that of other carnivorans and social hunters that have been tested, and some but not all domestic animals.
“Physical cognition is not a domain in which dogs excel, and their performance is at least equaled by other members of all three of our comparison groups.
“In spatial tasks, dogs have shown good performance, but the same is true of other species in all our comparison groups, and we have no evidence that they stand out as exceptional in this domain.”
Dogs have an impressive ability to use social cognition or other animals’ behaviour – particularly that of humans – as a cue.
But Prof Lea said: “However, some other carnivorans are even better at these tasks, and some other domestic species may do as well as dogs, though no other social hunters, except for wolves, have been shown to do as well.
“In experiments carried out so far, chimpanzees are more likely than dogs to solve tasks requiring perspective taking, though the evidence base for dogs’ perspective taking is improving, and dogs may do better than chimpanzees in cooperative situations.
“Chimpanzees are more likely than dogs to show evidence of deception or empathy.
Except for a claim of episodic-like memory, we have no firm evidence of self-consciousness in dogs.
“The same is true of other carnivorans and domestic animals, but two social hunters, chimpanzees and dolphins, have reliably shown such evidence.”
The findings follow a study last year by Japanese scientists that showed cats are just as intelligent as dogs when it comes to ‘episodic’ memories.
Episodic memory is the ability to remember autobiographical and contextual details of events like where and when they happened.
That team said cats may be as intelligent as dogs – as opposed to the common view of people that dogs are much smarter.
Prof Lea added: “We hope we can now begin to use our knowledge of dog cognition to go beyond the study of dogs and look at more of the comparator species.
“And, of course, in doing so, we will also expand our understanding of what, fundamentally, a dog uniquely is.”
By Ben Gelblum and Mark Waghorn