I had just bought a cup of coffee at a coffee shop when I noticed that Sam, a member of the faculty at my university, was waving at me. He gestured in a manner that indicated that he wanted me to join him at the small table where he was sitting. When I sat down, he pointed to the woman beside him and said, "My wife Edie thinks that I am crazy, and since you are a psychologist and also know a lot about dogs, she wanted to ask you about a situation."
Edie (a handsome woman whose hair was just starting to show some streaks of gray) leaned toward me and explained, "Sam takes a few professional trips each year to go to scientific meetings or to speak at other universities. When he is away he is really good about calling home each night to check on what's happening with me and the kids. But he always finishes his phone calls in a strange way—by insisting that I turn on the telephone speaker so that he can talk with Jesse, our Poodle. He then spends a few seconds spouting some nonsense to the dog, like 'Jesse, how's my girl? Do you miss me, Jesse? Love ya, Jesse!' Sam claims that Jesse recognizes his voice and forms a mental image of his face. And if that is the case, he claims that the sound of his voice should make her happy and comfort her in the same way that hearing their mother's voice might make kids feel good. I think that that is nonsense. Dogs may or may not reliably recognize particular human voices, but even if they do, it is unlikely that they actually form a mental image of the person that they are listening to."
There are actually a number of behavioral scientists who would probably agree with Edie. Consider this case in humans. You hear two of your family members speaking behind a closed door. You immediately picture the individuals involved, and when you open the door to join them, there they are, looking exactly as you'd imagined. Without any real effort, and quite unconsciously, you have just performed two actions of great interest to cognitive psychologists. To be precise, the first is an act of cross-modal perception (in this case by using the sound information associated with the voices to create a visual image of the people involved), and the second is a recognition task, identifying the people involved and associating them with particular memories. Some researchers feel that tasks like these might be difficult, or impossible, for dogs to complete. Actually most of their doubts focus on the idea that dogs are able to form mental images of particular human faces, since that implies a high level of consciousness, which is still a matter of scientific debate.
In the 14,000 years or more since domestic dogs diverged from their wild canine ancestors, man's best friend has developed a variety of social skills to help him get along with people. Being able to recognize human voices and attach them to faces could be extremely useful in social interactions with humans if it were one of those skills. Ikuma Adachi, a psychologist at Kyoto University in Japan, headed a research team that set out to investigate whether dogs might have evolved the ability to form mental images of individual humans. This report was published in the journal Animal Cognition*.
The study, which was rather straightforward, involved 28 dogs and their owners. In each experimental session a dog was positioned about a meter away from a computer monitor, which was hidden behind an opaque black screen. Next, through the monitor's speakers, the researchers played a recording of either the owner or a stranger saying the dog's name five times. Finally, the researchers removed the screen so the dog could see an image of either its owner's face or the face of a stranger on the monitor. Video cameras recorded the dog's reactions.
Now here is the trick in this study: Suppose that the dogs had heard their owner's voice, but then they were shown a picture of a stranger coming from the very place where they anticipated that they would see their owner's likeness. If the dog has a mental image of its owner then this situation violates its expectation and is apt to produce a "Huh?" response. As humans, when we have such a response we do a double-take, which means that we tend to stare at the surprising or incongruent situation in front of us for a much longer time than we would look at a situation where everything turned out exactly the way we expected. Some clever psychologists have worked out procedures where they can use the time that young human infants stare at things as a measure of their problem-solving and face-recognition abilities. Similarly, this same technique has been used to show that dogs can do simple arithmetic (click here to see more about that).
The results of this recent Japanese study are very clear—that is to say, they found that the dogs spent a longer time looking at the face when they were presented with a stranger's likeness after hearing their owner's voice than they spent looking at the monitor when it displayed their owner's face. The reverse is also true: If the dogs heard a stranger's voice and then were presented with an image of their owner, this mismatch also produced the "Huh?" response that shows up as additional time spent staring at the monitor. The interpretation of these results that these investigators offer is that the sound of an owner's voice conjures up a mental image of the owner's face, and that explains the confusion and additional staring that the dogs show when another face appears.
I explained this research to Edie and then asked her what Jesse did when she heard Sam's voice calling her name over the telephone speaker.
She answered, "Jesse sort of cocks her head to the side, wags her tail a bit, and sometimes may give a little bark."
"Well," I suggested, "Jesse certainly can't be anticipating that the phone is going to give her treats, so based on this research it may be that she actually is having a mental image of Sam's face when she hears his voice, and it just might be giving her a bit of pleasure."
Edie gave a dismissive wave of her hand and said, "I still think that it's crazy to talk to your dog over the phone!"
Stanley Coren is the author of many books including: The Wisdom of Dogs, Do Dogs Dream?, Born to Bark, The Modern Dog, Why Do Dogs Have Wet Noses?, The Pawprints of History, How Dogs Think, How To Speak Dog, Why We Love the Dogs We Do, What Do Dogs Know?, The Intelligence of Dogs, Why Does My Dog Act That Way?, Understanding Dogs for Dummies, Sleep Thieves, and The Left-hander Syndrome
Copyright SC Psychological Enterprises Ltd. May not be reprinted or reposted without permission
Data from: Adachi I, Kuwahata H, & Fujita K (2007). Dogs recall their owner’s face upon hearing the owner’s voice. Animal cognition, 10 (1), 17-21