I have a ring tone on my mobile phone that I really like. It barks. Five barks (bark-bark-bark-bark-bark) for each ring. It is a real dog’s voice, not a person fake-barking in that annoying way that certain people feel compelled to do when they see a dog. (Really, what is that about anyway?). Earlier this week, my phone started barking while I was getting my hair cut. My hairdresser laughed and asked if any of my dogs react to the barking phone. I told him that no, they always ignore it, which is strange, since it is definitely the recording of a real dog bark.
To which he replied “Maybe the dog isn’t saying anything”.
Maybe. But recent research suggests that dogs do have something to say and that other dogs are often quite interested in hearing what that is.
Background information: The auditory (vocal) signals that animals make often have important communication functions and possess context-specific information. This means that a sound may be conveying information about several things at once. For example, an alarm call may vary in subtle but detectable ways depending on the location of the threat and how dangerous it is. Vocalizations may also be important signals that allow animals to recognize and identify one another. Indeed, this ability has been demonstrated in a wide range of species of birds, mammals, and even amphibians.
So, what about dogs? Previous research has shown that like many other animals, the sounds that dogs make are varied and highly context-specific and that humans, especially those who are experienced with dogs, are quite capable of distinguishing between different types of dog barks (1,2). However, while it is easy to test a human’s response to dog barks (we can just ask them questions), it is more difficult to ask dogs what they are learning when they listen to the vocalizations of other dogs.
Difficult, but not impossible. A group of ethologists at the Eotvos Lorand University in Hungary recently designed two clever experiments in which they were able to ask dogs – What are other dogs saying to you when they bark?
The technique: The reseachers used an approach called “habituation-dishabituation” to measure dogs’ reactions to the recorded sounds of barking. The technique works like this. The dogs were first allowed to habituate to recordings of a particular dog who was barking in a particular situation. Habituation was measured by recording the number of seconds that the listening dog continued to show interest in a dog/situation combination over time. A decrease in attention was interpreted to indicate habituation. A dog would stop reacting to the sound as it lost significance much in the way we habituate to the sound of our air conditioner kicking on because it is heard repeatedly through the day. Then (here is the clever part), the researchers changed either the identity of the dog who was barking or the context of the bark. The introduction of something that is new or unexpected should cause dishabituation, but only if the listener notices the change. (For example, if your air conditioner suddenly started making a rattling noise, you would dishabituate to it and take notice, right?). In this case, if the listening dog responded by suddenly increasing his/her attention to the recording, this means that the dog noticed the change and so was capable of distinguishing between different dogs and/or different causes of barking. If on the other hand, the change did not cause a change in the listener dog’s behavior, such a result would indicate that the dog had habituated to the general sounds of a dog barking and was not gleaning any specific information from the recordings. The group of investigators published two studies with dogs using this technique.
Study 1: The researchers recorded the barks from five adult dogs in two different contexts; either in response to an unfamiliar person approaching a garden area or when left alone, tied to a tree in a park (3). They then brought 30 other dogs into the lab and played the recordings from a hidden recorder, first allowing habituation to a particular dog/situation and then, for the dishabituation test, changing either the dog or the cause. Results: The subject dogs consistently showed an increase in interest to the recordings in response to both a change in identity of the dog who was barking and also in response to a change in the cause of barking. These results suggest that dogs are capable of differentiating who is barking when they hear another dog and what the dog is barking about. What this study design could not tell us however, is what exact type of information (if any) the dogs were gleaning from the recorded dogs or if they were capable of identifying a known individual by his or her bark.
Study 2: This time around, the researchers asked the question – Do dogs recognize the barks of other dogs who they know and do they react to what their friends are barking about (4)? A group of 16 dogs, all living in multiple-dog homes, were tested. The dogs were tested in their own homes (so had an attachment to the context) and they listened to a hidden recording of either an unfamiliar dog or of one of their housemate dogs (who was not present at the time, because that would just be weird). The two situations were the same – barking when left alone or barking at an unfamiliar person approaching the yard’s fence. Each dog’s reactions were videotaped to allow careful analysis of any changes in behavior while listening to the recordings. Results: The dogs showed specific behaviors that depended upon who the barker was (friend or stranger) and upon what was causing the barking (isolation or territorial). Upon hearing a recording of their housemate, dogs would move toward the house where the dog was expected to be. Conversely, they moved toward the yard’s gate when they heard the sound of an unfamiliar dog barking at a stranger. The listener dogs also barked most frequently in response to the “stranger coming” recordings, regardless of whether the bark came from their housemate or a stranger. The researchers concluded that dogs appeared to be able to identify other dogs “by bark” and that they also obtained information about a bark’s cause, simply by listening, in the absence of other cues such as the barking dog’s body language or facial expressions.
Take Away for Dog Folks: The results of this study instruct us (once again) to take care with our assumptions when working with dogs. While it should be naturally obvious that dogs are proficient at recognizing and understanding one another via vocalizations and that a great deal of information is conveyed via barking (and I would bet a few of you were shaking your heads whilst reading and muttering, “well, no kiddin'”), we often do not behave as though we actually believe this to be true. Here is what I mean.
Dog owners, trainers and behaviorists frequently classify barking in dogs as a problem behavior. If we don’t like it, if it annoys us, if we deem it excessive or an attention-seeking behavior, then it immediately gets dumped into the “behavior problem” bin. Well, granted, excessive barking can be annoying, can pose a community nuisance, and as a recurrent behavior may need some modifying. (Believe me, I understand vocal dogs – I live with a Toller). However, perhaps as humans we have become so intolerant of dogs barking that we may occasionally stop seeing it for the important communication tool that it is in our efforts to stop it.
Up on the ol’ box: Moreover, we may often get it wrong. Barking that is classified as problematic because it is thought to be “attention-seeking” could in actuality be a legitimate bid for affection from a chronically neglected dog. Or barks that an owner is instructed to ignore so as to “extinguish the behavior” may in fact be conveying true distress. (See “Is it time for the extinction of extinction?” for more about this). Is it also not possible that a dog who shows alarm barking truly has something to be alarmed about? While I am not suggesting that we should allow all dogs, at all times, to bark to their little heart’s delight (though, that is certainly what Chippy my Toller is going for), I am advocating that just as we accept body postures, facial expressions, eye contact, elimination patterns, and touch (tactile signals) as important forms of communication in our dogs, so too we should accept (and decriminalize) barking.
As trainers and behaviorists, perhaps it is time to dial back the trend towards classifying any barking that an owner does not like as “attention seeking”, “demand”, or “nuisance” barking, and reclassify it as a normal communication pattern that warrants understanding of the cause and as needed, modification. As the very chatty species that we are, we should be sensitive to and wary of any training approach or behavior modification program whose goal is to produce a completely silent dog.
As for my barking phone, I will continue to enjoy it, even if the dog is speaking nonsense. And Chippy the Toller, of course, says “Bark on, man, bark on”.
- Pongracz P, Molna Cs, Miklosi A, Csanyi V. Human listeners are able to classify dog barks recorded in differenct situations. Journal of Comparative Psychology 2005; 119:228-240.
- Pongracz P, Molna Cs, Miklosi A, Csanyi V. Acoustic parameters of dog barks carry emotional information for humans. Applied Animal Behavior Science 2006; 100:228-240.
- Molnar C,OPongracz P, Farage T, Doka A, Miklosi A. Dogs discriminate between barks: The effect of context and identity of the caller. Behavioural Processes 2009; 82:198-201.
- Pongracz P, Szabo E, Kis A, Peter A, Miklosi A. More than noise? Field investigations of intraspecific acoustic communication in dogs (Canis familiaris). Applied Animal Bahavioual Science 2014: In Press.