The ability to follow the direction of a gaze even around a barrier is a key tool in nonverbal communication between individuals. Previously, this ability had only been observed in birds and primates. Friederike Range and Zsófia Virányi of the University of Vienna have now detected this behavior in captive wolves.
There are two key components to the gaze test. The first is to see whether the test subject will follow a gaze into the distance. In other words, will the animal look in the same direction as the tester is looking? If so, then the animal understands that there may be something important going on where the tester is looking. Many types of animals, including wolves, birds and even a tortoise can pass this test.
Gaze following into distant space.
A: control trial; B: test trial.
The second, more complex test is to see whether the animal will follow a gaze around a barrier. If the tester appears to be looking at something that is blocked from the animal’s view, will the animal shift its position to investigate? Far fewer animals can make this cognitive leap, but wolves happen to be one of them. However, when the wolves repeatedly found nothing of interest behind the barrier, they stopped paying attention to the testers’ gazes in that direction. In contrast, they did not habituate to stares into the distance, but continued to look in the direction their handlers were looking. This may indicate that following a gaze around a barrier requires a different cognitive process than simply following a gaze into the distance.
Layout of the barrier test, showing the position of the human E 1 and the start position of the test subject.
E2 held the subject on the collar or leash until the gaze cue was given. The arrows indicate where E 1 looked in the test and control conditions respectively.doi:10.1371/journal.pone.0016888.g001