TORONTO - Longtime dog lovers swear their pets can read their minds. Perhaps that's because the brains of people and their pooches have a lot more in common than previously thought.
"Darwin basically said that anything that is useful doesn't just appear out of nothing," said Stanley Coren, an author, psychologist and dog researcher who was speaking Saturday at the American Psychological Association's annual convention in Toronto.
"We'll begin to see glimmers of it in more primitive form in other species. And I think that's the way it works when it comes to consciousness."
Research shows dogs have similar intelligence to a 24-to 30-month old child, Coren said. For the record, cats are considered to have the intelligence of an 18-month-old.
The average dog has a vocabulary of about 165 words. The smartest canines understand up to about 250 words and are able to figure out new ones on their own.
"That kind of fast language learning we thought was only possible among humans and some of the higher apes."
But more than that, tests suggest that dogs and apes both have some of the same basic emotions - fear, anger, disgust and pleasure - that toddlers experience, said Coren, while both the animal groups are missing some of the more complex, learned emotions such as guilt.
"What we tend to be interpreting as guilt is really fear on the dog's part. They get the impression you're going to drop a piano on their head for something they've done wrong."
Coren suggests smarter dogs can count reliably to five and can spot errors in rudimentary arithmetic. They can also learn basic abstract geometric concepts such as big and small.
Dogs may even understand fairness.
In one experiment, a researcher trained two dogs to shake a paw. After both learned the trick, the researcher started giving a treat to one of the dogs every time he got it right but not to the other.
Not only did the unpaid dog stop performing, he wouldn't even look the researcher in the eye.
"He doesn't want any part of you. He doesn't think this is fair."
Scientists are beginning to believe there are so many similarities between youngsters and dogs that canine researchers are adapting tests developed for young children.
"Since we've now found roughly what the intellectual level of the dog is, we now have people who are modifying various types of tests, which we use on young human children in order to determine what the dog is doing."
"Does a dog feel bored? Does he feel lonely, or love? "
It's all leading to a more accurate understanding of the relationship between humans and animals, Coren said.
On one hand, there are people who see animals - especially their pets - as tiny humans in fur coats. On the other, there are those who think of animals as genetically programmed robots.
The truth, suggests Coren, is somewhere in the middle.
"We're not going to send (dogs) to Harvard, but it's a sign that these glimmers are there."
Intelligence also seems to vary between breeds. Older breeds such as some hounds and terriers have less going on upstairs than breeds such as retrievers or herding dogs.
Not that that's necessarily a bad thing. Smart dogs need more attention.
"If you don't work them, they become neurotic," Coren said. "And they're smart enough to make you neurotic, too."
"Sometimes, it's better to have a dog that's not so intelligent."
For example, it's a good bet that a Doberman pinscher left alone all day will chew up the couch and smash vases.
"If it's an English bulldog ... it'll take them eight hours to figure out you're gone."