 |
| If a human first gets the attention of a dog, the dog will follow the direction of the person's gaze. |
By Sarah C. P. Williams, Science Now, January 5, 2012
Sit a dog in front of a television screen, and it may
not always look intently at what it sees. But show a person on that screen who
looks directly at the dog and says "hello," and the canine will pay
attention. In fact, a new study shows that a dog will go so far as to follow
the gaze of the human on screen when he or she looks to one side or the other—something
not even chimps can do.
Researchers already knew that dogs were attuned to human
communication signals. In addition to their obvious facility at learning
commands, dogs, like young children, can signal where a human puts an object if the human feigns
ignorance, even if it's been moved, and they follow the direction of our finger
when we point at things, a task chimps fail at. But are dogs capable of
following more subtle cues, such as our shifting gaze?
To find out, cognitive scientist Ernő Téglás of the Central European University in Budapest
adapted a technique that had previously been used only on children. In one
example of the test, a child watches a woman on a video screen who has toys on
either side of her. The woman then either looks straight toward the camera and
says "hello" in a high-pitched voice known to engage children or
looks downward and says "hello" in a more dull, low-pitched voice.
Then the person looks to the toy on one side or the other for 5 seconds.
Whether a child also looks at the toy on the same side is recorded. To modify
this experiment for dogs, Téglás substituted empty plastic pots for the
children's toys and had a stranger on the screen say "hi, dog!" in
one of the two intonations while looking at the camera or downward. As each dog
watches the video, a specially programmed camera below the television screen
follows, and records, the dog's eye movements.
Téglás and his colleagues used 22 dogs of different
breeds for the study. They found that the canines always looked at the person
on the video for the same amount of time. But when the person initially
directed his or her attention at the dog and spoke in a high-pitched voice, the dog looked at the same pot as the
person 69% of the time. When the person avoided eye contact and spoke in a low voice,
the dog didn't look at one pot more often than the other.
The results, published today in Current Biology, were
almost identical to those seen in 6-month-old human infants. "We were
surprised by the high similarity of the performances," Téglás says.
"Dogs are receptive to these cues in a way that is very similar to
infants."
The precision of the eye-tracking device will allow
scientists to develop a new generation of tests on how dogs interact with
humans, says Juliane Kaminski, a developmental psychologist at the Max Planck
Institute for Evolutionary Anthropology in Leipzig, Germany, who was involved
in earlier studies on how dogs interpret finger pointing. "It opens many
new opportunities."
Now that the scientists have shown that the test works
on dogs, they plan to separate the two factors—eye contact and tone of voice—to
test each one's effect on the dog's attention, Téglás says. They also can
compare different dog breeds with each other. This may help answer the question
of how dogs' skills at interpreting human communication have evolved.
"Dog skills with human communication seem to be a special
adaptation to live with humans and the result of certain selection pressures
during domestication," Kaminski says. If this is true, researchers would
expect dog breeds that have been domesticated the longest to perform best at
tests such as gaze following. But don't plan on being able to compare your dog
with all the other neighborhood canines—dogs likely interpret the cues from
their owner differently than those from a stranger.
No comments:
Post a Comment