When humans turned wolves into dogs, we created a social companion that keys in on our every move and look. That attentiveness was one of the big effects of domestication, some scientists have argued, and a clear difference between the two species. But wolves raised with humans also pay close attention to our actions and even follow our eye gaze, say two researchers. They even pass a gazing test that dogs fail.
The findings "seem to put a big nail in the coffin" of the dog-domestication theory, says Frans de Waal, a primatologist at Emory University in Atlanta who specializes in social cognition. The results should also help researchers better understand the evolution of gazing abilities overall, say the authors of the new study.
Previous studies have concluded that wolves are not interested in human social cues and will not, for example, follow a pointing finger, even if that finger would lead them to food. By contrast, dogs seem to instantly grasp the connection. "For a dog, understanding pointing is a natural thing to do," says Friederike Range, a cognitive ethologist at the University of Vienna and the lead author of the new study. "But how important is pointing to a wolf naturally?"
Because it's not possible to test wild wolves' abilities to follow a person's gaze, Range and her co-author, Zsófia Virányi, a cognitive ethologist at the Wolf Science Center in Ernstbrunn, Austria, hand-raised nine wolf pups born in captivity. The pups were separated from their mothers 10 days after birth and bottle- and hand-fed for their first 5 months of life. In the ensuing months, the wolves continued to have daily social contact with humans and five adult dogs of various breeds, with which they developed close relationships. Like trainers raising dog puppies, the scientists gave the wolf pups intensive obedience training, teaching them to sit, lie down, roll over, and look into a person's eyes.
When the pups were 14 weeks old, Range and Virányi tested their ability to follow the gaze of a person who turned her head and looked into the distance. Six of the pups passed, turning to look in the same direction only seconds after the person did. And at 23 weeks old, all the pups passed the test, the team reports online today in PLoS ONE.
This gaze-following ability was once thought the exclusive domain of humans. Scientists believed it evolved because we alone understood that other people have minds and thoughts. But in recent years, that barrier has been breached by apes, monkeys, goats, ravens, and a tortoise. Now that we know it's common among animals, Range says, scientists need to revise their theories about why it evolved.
Only domesticated dogs have failed the test of following a person's gaze to look into the distance. "That is a clear difference between dogs and wolves," says Marc Bekoff, a cognitive ethologist at the University of Colorado, Boulder. Scientists don't yet know why dogs fail this test, but it may be because "we train them to look at our eyes and face and not to follow our gaze," says Range.
In a second experiment, the researchers tested the wolf pups to determine whether they would follow the gaze of a person as she stood staring at a spot on the other side of a low wall. The wolf could see what the person was looking at only if it walked around the barrier. The duo also used the wolf pups' dog companions as demonstrators, giving the dogs verbal commands to focus on the other side of the wall. Only four of the nine pups passed the test at 4 months old. But when they were 6 months old, all of the wolves reliably followed the person's and the dogs' gazing cues.
Of the species that have passed the gazing-in-the-distance test, only apes, rooks, ravens—and now wolves—have nailed this far more difficult exam. "It really surprised us that wolves would follow our gaze [around a barrier], because it's always been thought that wolves don't pay attention to humans, that they don't see us as social partners," says Range.
The two types of gaze-following abilities seem to require different mental skills, she adds. It may be that the talent for following another's gaze while looking in the distance is innate, almost a "reflexive reaction," she says. But the ability to understand that your social pal is looking at something behind a barrier may develop only in species that are either highly cooperative or highly competitive—something that needs further testing, Range adds.
"It's a great study and the first, I think, that really is really biologically relevant to wolves," meaning that it tests their natural propensities, says Bekoff. "It's very important" to do studies like these "on socialized wolves," adds Adam Miklosi, a cognitive ethologist at Eötvös Loránd University in Budapest. "We can then put our knowledge" about dogs into a "wider evolutionary perspective" and ultimately arrive at a better understanding of how domestication turned the wolf into a dog. That's a change, researchers say, that required wolves to begin thinking of humans as their social pals if they were ever to end up asleep at the end of our beds.