Has our co-evolutionary relationship with dogs made them dimmer?
An Oregon State University study on dog intelligence suggests that the answer to that question might be yes.
Dogs are among the top brainiacs of animal kingdom. Much of that intelligence stems from the nature and nuances of the human-canine relationship. After thousands of years of co-evolving with humans, dogs can recognize human facial expressions, learn vocabulary, and execute all manner of nifty tasks and tricks on command.
Studies of dog intelligence have often pointed to dogs' reliance on humans as an indicator of their intelligence. When confronted with an unsolvable task, dogs immediately look to their human companions for help. When confronted with the same unsolvable task, human-socialized wolves ignored the humans and continued trying solve the task themselves.
This particular study, from the University of Budapest, led researchers to conclude that the dogs' dependency on human help indicated superior problem-solving abilities compared to those of the human-socialized wolves.
However, a study from Oregon State University has interpreted dogs' reliance on humans a bit differently. Associate Professor of Animal and Rangeland Sciences Monique Udell believes that dogs' dependency on humans for help in solving difficult tasks suggests "a conditioned inhibition of problem-solving behavior."
In other words, we've made our best friends a little dimmer.
Udell set out to test her hypothesis by testing the problem-solving skills of ten pet dogs, ten human-socialized wolves, and ten shelter dogs. The shelter dogs were used as an intermediate step between the pet dogs and the human-socialized wolves, because past research has suggested that they are less receptive to humans than pet dogs are.
For the experiment, Udell placed a sausage treat inside a plastic container. She sealed the container and attached a piece of rope to the lid so that, with some combination of teeth and paws, it could be opened.
Udell gave each subject two minutes to solve the puzzle and get to the sausage treat inside. She presented the puzzle twice: once in the presence of humans (in each case, the only human present was familiar to the animal), and once in the absence of humans. If a subject failed both tests, Udell gave the subject a third try, during which the subject's familiar human provided verbal coaxing.
The findings told an interesting story. With humans present, eight out of ten wolves solved the puzzle, but only one pet dog was able to solve it. All of the shelter dogs failed the test.
Moreover, Udell noted that the wolves spent a great deal more time staring at the container and mulling over how to open it. None of the dogs made such prolonged, independent attempts. All of the dogs abandoned the challenge relatively quickly and looked to their human companions for help.
In the absence of humans, the findings told a similar story. The majority of the wolves succeeded in opening the container. But only one shelter dog succeeded. All of the pet dogs failed.
The subjects who failed both attempts fared a bit better on their third try. With some encouragement from familiar humans, one of the pet dogs and four of the shelter dogs made more robust attempts to solve the puzzle without help, and eventually succeeded.
The fact that the wolves were more successful problem solvers in all experimental scenarios suggests that dogs' reliance on humans might be negatively impacting their problem-solving capacities. The cause for this disparity between the dogs and the wolves, be it environmental, biological, or some combination thereof, is an important question for future research into dog intelligence.
You can read more about Udell's illuminating study in the journal Biology Letters.