By Elizabeth Pennisi
Dog-owners have no doubt that their pets are, in many ways, just like people. Dogs speak when spoken to, play games, and even eat with the family. Now researchers have discovered yet another human trait that pooches possess: selective imitation. Dogs mimic each other's behavior, but only when they think that behavior might be a more efficient way to get something done. The discovery indicates that this type of imitation--a prerequisite for cultural learning--may predate primates.
Humans regularly evaluate the actions of others and decide whether or not to copy them. In 2002, researchers discovered that infants do this too. In one experiment, 3- to 12-month old babies watched a female researcher turn on a light box by touching its top with her forehead, not her hands. If she wrapped a blanket around her body during the demonstration, the babies activated the box with their hands--a more efficient way of turning on the lights. They recognized that the woman couldn't use her hands and had to use her head. But when the researcher performed the task without the blanket, a second group of infants opted to copy her head-movements, as if deciding that if the woman did it, then it must be a better way to go. This ability to learn selectively by example, which has also been seen in apes, is key to picking up language and other social skills efficiently.
To learn more about the evolution of this selective mimicking, ethologist Friederike Range of the University of Vienna, Austria, and colleagues tested whether dogs can also make these decisions. The researchers divided 54 dogs of various breeds into three groups. One group watched a border collie trained to get food by pressing down a bar using just its paws, and not via the easier technique of grabbing it with its mouth. Another watched the same behavior, but this time the border collie had a ball in its mouth. A third group did not witness any demonstrations.
In the first instance, 83% of the dogs imitated the dog using its paws to get the treat. In the second, just 21% used their paws, and in the third, only 15% used their paws. As with the infants turning on the light box, the dogs only imitated another dog when they assumed its behavior was the most efficient way to get a treat, the team reports online today in Current Biology.
The fact that dogs have this behavior suggests one doesn't need the full repertoire of human cognitive skills to selectively imitate the actions of another, says Range. What's unclear, she notes, is whether dogs have evolved this ability independently, or because of their close connections with humans.
"This is an intriguing study, not just because it's the first good evidence of imitation in dogs, but because on top of that, we see a quite sophisticated level of selectivity in what the dogs are prepared to copy," says Andrew Whiten, an evolutionary psychologist at the University of St. Andrews in Fife, the United Kingdom. But György Gergely, a psychologist at the Hungarian Academy of Sciences, Budapest, says further testing--as was later done with infants--is needed to conclusively show that dogs are thinking on the same level as humans.