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research
News: Editors
Researchers have come up with another reason why we are attracted to irresistible photos of puppies and kittens, and another reason that we can never get our fill of these adorable photos.
Psychological scientists from Florida State University, led by James K. McNulty, are using cute animal photos to rekindle marriages that might be in the doldrums. These researchers were tasked by the Department of Defense to come up with a strategy “to help married couples cope with the stress of separation and deployment.” McNulty and his team set out “to develop a procedure that could help soldiers and other people in situations that are challenging for relationships.”
Using techniques developed by none other than Pavlov, they employed a positive feedback mechanism called evaluative conditioning. They would show images of a spouse that were repeatedly paired with very positive words or images (like puppies, kittens and bunnies). In theory, the positive feelings elicited by the positive images and words would become automatically associated with images of the spouse after practice.
Each spouse was asked to individually view a brief stream of images once every 3 days for 6 weeks. Embedded in this stream were pictures of their partner. Those in the experimental group always saw the partner’s face paired with positive stimuli (e.g., an image of a puppy or the word “wonderful”) while those in the control condition saw their partner’s face matched to neutral stimuli (e.g., an image of a button). Couples also completed measures of automatic partner attitudes and explicit marital satisfaction at baseline and once every two weeks for 8 weeks
The study concluded that “spouses who viewed their partners paired with positive stimuli demonstrated more-positive automatic partner attitudes than did control spouses, and these attitudes predicted increased self-reported marital satisfaction over time.”
As McNulty noted that the positive completion of the study:
“I was actually a little surprised that it worked,” McNulty explained. “All the theory I reviewed on evaluative conditioning suggested it should, but existing theories of relationships, and just the idea that something so simple and unrelated to marriage could affect how people feel about their marriage, made me skeptical.”
Good Dog: Studies & Research
Puppy mill dogs have more behavioral problems
“We found that across all behaviour categories, including trainability, dogs from less responsible breeders had significantly less favourable behaviour and temperament scores than puppies from responsible breeders.”
The above statement by researcher Catherine Douglas sums up the study “Do puppies from ‘puppy farms’ [puppy mills] show more temperament and behavioural problems than if acquired from other sources?” More extensive results were presented at the annual conference of the British Society of Animal Science.
It was the first study in the UK on the behavior and temperament of adult dogs who came from puppy farms, which we call puppy mills on this side of the Atlantic. Dogs were divided into two categories. One set came from puppy farms or other commercial breeding facilities that did not follow the good practice standards of the RSPCA or the Animal Welfare Foundation’s Puppy Contract (less responsible breeders). The other group in the study was made up of dogs who came from responsible breeders who put a priority on the welfare of the breeding dogs as well as of the puppies (responsible breeders).
Dog guardians filled out surveys about the conditions of the facility the dog came from to determine whether the dog came from a puppy farm (or similar) or from a responsible breeder. They were asked such questions as “Were the puppies raised in a home environment? Did you see the mother? At what age did you get your puppy?” They also filled out a standard survey (the CBARQ, or Canine Behavioral Assessment & Research Questionnaire) to evaluate their dog’s behavior. The breeds studied were the Pug, the Jack Russell Terrier and the Chihuahua.
Though there have been many studies about the physical health of dogs from puppy farms, there is far less research about the adult behavior of these dogs. The results of this study overwhelmingly support the common advice NOT to buy a dog from such a place. In every category, the dogs from less responsible breeders were found to have less desirable behavior than dogs from responsible breeders. Specifically, they were more likely to be aggressive to members of the household, more likely to be aggressive to strangers, more likely to be aggressive to dogs, more likely to be fearful of new objects, more likely to have noise phobias, more likely to suffer from separation anxiety, and less likely to be rated high in trainability.
It’s not clear what factors contribute to these extensive differences in temperament and behavior, but there are many possibilities. Stress during pregnancy can contribute to anxiety in puppies and affect their ability to learn in training. Being separated from the mother while very young can also have detrimental effects on adult behavior. There could also be genetic factors that account for some of the differences between the two groups of dogs.
Though the results of this study are not surprising, they do confirm that where we get our dogs matters. Acquiring dogs from puppy farms supports an industry that lacks proper safeguards for animal welfare and also makes it less likely that your best friend will be the ideal companion and family member that we all want.
Good Dog: Studies & Research
Interactions with guardians offer some relief
Veterinary examinations are stressful for dogs, and being stressed is counterproductive to general well-being. We don’t want our dogs to suffer, especially when the purpose of seeing the veterinarian is to help them. Another issue is that the effects of stress—both the behavioral and physiological responses—can make it harder to examine the dog thoroughly and properly diagnosing the dog becomes harder as well.
A recent study examined the effects of contact with the guardian during veterinary exams on the stress levels of the dog. The basic conclusion of the study was that it is beneficial to dogs for their guardians to interact with them with physical contact and verbal communication. Dogs were less stressed by several measures when their guardians interacted with them compared with just having their guardian present in the room.
Every dog was studied during two visits to the veterinarian—one in which the guardian talked to and had physical contact with the dog, and one in which the guardian was present in the room but did not interact with the dog. The canine behaviors observed were panting, vocalizing, attempting to jump off the exam table, struggling, lip licking, yawning and paw lifting. The physiological measures were heart rate, cortisol levels, maximum ocular surface temperature and rectal temperature. All behaviors and physiological measures are associated with stress in dogs.
When guardians were allowed to talk to and pet their dogs (the “contact” condition), the dogs attempted to jump off the table less often and vocalized less than dogs whose guardians were present but not interacting with the dog (the “non-contact” condition). There were no differences in any of the other stress-related behaviors. On the physiological side, dogs in the “contact” condition did not have as large an increase in heart rate or maximum ocular surface temperature as the dogs in the “non-contact” condition did. There were no differences between the two conditions in rectal temperature.
This study offers some encouragement about our ability to make a difference to our dogs’ stress levels when at the veterinarian. The results suggest that interactions with the guardian may be more effective than just the physical presence of the guardian, but the effect is not striking. By many measures, there were no differences. The behavioral measure that did differ—vocalizing and trying to jump off the exam table—may do so because both of those behaviors could be an attempt to make contact with the guardian. Dogs do often vocalize as a response to separation, and dogs who try to jump off the exam table may sometimes do so as an attempt to make contact with their guardians.
Good Dog: Studies & Research
“Calming signals” is a term coined by Norwegian dog trainer Turid Rugaas to group a large number of behavior patterns that she says dogs use to avoid conflict, to prevent aggression, to calm other dogs down and to communicate information to other dogs and to people. Since the publication of Rugaas’ 2006 book On Talking Terms With Dogs: Calming Signals, it has been a popular idea that actions such as lip-licking, sniffing the ground, yawning, scratching, looking away, play bowing, sitting down, lying down, softening the eyes, blinking and even sneezing (along with many others) are social signals that help calm down those around them.
Rugaas’ observations are compelling, and many dog trainers and behaviorists, including me, have learned a lot from her work. However, the term “calming signals” entered the lexicon without much analysis, which is problematic. Using a term that ascribes functionality to behavior patterns prior to scientifically testing whether or not that’s true creates challenges, and is a big no-no in ethology. One problem is that claiming that certain behaviors are “calming signals” creates a bias such that people tend to accept that this is, in fact, what they do. The idea that these signals are functioning in this way is an intriguing hypothesis. However, in the years since Rugaas shared her ideas with the dog community, there have yet to be adequate tests of their function, or substantial efforts to determine if the various behaviors have different functions. Rather, the idea that they were calming signals was broadly accepted without being subject to rigorous scientific study.
There is, however, a recent pilot study investigating the function of the behavior patterns that have all been placed into the category of calming signals. The purpose of the study “Analysis of the intraspecific visual communication in the domestic dog (Canis familiaris): A pilot study on the case of calming signals” was to assess if the behaviors that have been called calming signals are used to communicate, and if they de-escalate potentially aggressive situations between dogs. In the study, 24 dogs were observed interacting two at a time. Dogs interacted with familiar and unfamiliar dogs of both sexes.
Throughout the course of the study, 2130 calming signals were observed, with the most common being head turning, nose licking, freezing and turning away. Dogs were more likely to display calming signals when they were interacting with the other dog compared with when they were not interacting, which does suggest a communicative role. It does not prove it, though, as it is possible that these behaviors indicate stress and that they are performed during social interactions more often than they are performed outside of that context because such interactions are stressful. In fact, most of the signals that Rugaas has called “calming signals” are also considered indicators of stress.
More calming signals were displayed when dogs were interacting closely (within 1.5 body lengths of the dog displaying) than when interacting at a greater distance. Overall, more calming signals were exhibited during interactions with unfamiliar dogs than with familiar dogs, but licking the other dog’s mouth was more frequently observed when the other dog was familiar.
During the interactions in the study, there were 109 instances of aggressive behavior. A calming signal never came right before the aggressive behavior, but 67% of the time, at least one calming signal followed the aggressive behavior. In over 79% of the instances in which a calming signal followed the start of the aggression, there was a de-escalation in the aggressive behavior. These data are consistent with the idea that these behaviors function to calm other dogs down and lessen their aggression, but the work is too preliminary to conclude this for certain. More research is needed to explore other possibilities, such as the role of stress in these behaviors and their effects, and the potentially different functions of each of the dozens of behaviors that have been lumped under the term “calming signals”.
This is a pilot (or preliminary) study, and though the results are intriguing, they are in no way a definitive test of the function of “calming signals” in dogs, which the authors correctly point out in their paper. Though this research makes an attempt to test the often-accepted hypothesis that many behavior patterns function as calming signals that de-escalate aggression, its biggest flaw is that it lacks a very important control. De-escalation of aggression is quite common, and in this study, the authors report the frequency of de-escalation after a calming signal, but do not report on the rate of de-escalation in the absence of a calming signal. Part of the problem is that with so many possible calming signals, it is quite likely that one will be exhibited as a response to aggression. (Dogs are unlikely to have no reaction to such behavior.)
To evaluate the function of the behaviors, it is necessary to know the frequency with which the aggression de-escalates in the absence of any calming signals. We know that there was often de-escalation in the absence of calming signals because the authors report that in quite a few cases, the dog on the receiving end of the aggression walked or ran away, increasing the distance between the two dogs, which was often associated with a de-escalation in aggression. Fleeing is not considered a calming signal, and yet when the distance increased between the two dogs, there was also usually a de-escalation of the aggression. Future research should explore the differences in behavior in cases in which there was de-escalation and in which there was not.
Good Dog: Studies & Research
People are able to interpret these vocalizations
Research in recent years has shown that our brains can process the emotional content of vocalizations based on acoustic structure, and that various mammalian species share the same brain structures used for such interpretation. That means that we ought to be able to interpret the emotional nature of vocalizations from other species much like we understand those of other people.
Multiple studies of communication across species have found that animals can understand the emotional nature of vocalizations made by members of other species. In a number of studies, experience with the other species enhanced the ability to understand calls from that species.
Cross-species communication is particularly interesting between humans and dogs because of the long history we have of associating with one another, leading to the possibility that we have influenced each other’s vocalizations. In order to investigate people’s ability to understand canine growls, researchers conducted a study in which people listened to recordings of dogs growling and were then asked questions about the emotional state of the dogs.
In the study, “Dog growls express various contextual and affective content for human listeners”, 40 people heard recordings of growling dogs. All of the growls were recording in one of three contexts: guarding food from another dog, playing tug with a person and being approached by a stranger. In the first part of the experiment, the people were asked to rate each growl on a sliding scale for each of the following emotions: fear, aggression, despair, happiness and playfulness.
The emotional profiles based on the 40 ratings of all three contexts were different. Food guarding had the highest aggression rating, followed by the stranger context, and the growls from play had the lowest aggression scores. For the other emotional states, the food guarding and stranger context did not differ from each other, but were rated higher in despair and fear than the playful growls and lower in playfulness and happiness than the growls recorded in play.
In the second test, people were asked in which of those three situations the growl was recorded. Overall, people correctly identified the context of 63% of the growls, which is significantly better than the 33% rate that chance predicts. The play growls were most readily identified, with 81% of them being correctly chosen. The food guarding growls were correctly identified 60% of the time, compared with 50% of the growls directed at strangers. Most of the errors in identifying these two (potentially aggressive) contexts involved confusion between the two of them, rather than with the playful context.
The authors conclude from this study that people can distinguish different types of dog growls, including being able to tell apart growls that are both in potentially aggressive contexts. Previous studies have found that people’s ability to understand canine growls is influenced by the time between growls and the duration of the growls. Based on analysis of the acoustic structure of the growls in this study, the key characters of the growls that make them seem different to people are the rhythm of the series of growls and the length of the individual growls within that sequence. Longer gaps between growls is associated with higher aggression scores. Shorter growls are generally perceived as more positive on emotional scales. In growls recorded in the context of a stranger approaching, the higher the pitch of the growl, the higher the fearfulness score.
Individual people varied in their ability to identify the context of the growls. Overall, women were better at it then men. Also dog guardians outperformed people who do not have dogs. Whether or not a person had ever been bitten by a dog had no effect on whether people were able to determine the context of a growl. This study shows that although people in general can interpret the emotion in canine growls, experience plays a role in how well they are able to do so.
Can tell what your dog’s growls mean?
Wellness: Food & Nutrition
A vet speaks out on genetically modified pet food.
Most dogs now dine on some type of genetically modified (GM) food, often in the form of corn and soy in their kibble. As these ingredients increasingly enter the food supply, we have one more reason to wonder if our shopping choices might be harming our pets.
More animal feeding studies are needed, experts say, and a recent long-term, peer-reviewed report points out why. It found that a diet of GM corn and soy led to higher rates of severe stomach inflammation in pigs, which are physiologically similar to dogs.
Robert Silver, DVM, a Boulder, Colo., holistic vet, tackled the issue earlier this year when he presented his paper, “Genetically Modified Food and Its Impact on Pet Health” at the American Holistic Veterinary Medical Association conference in Kansas City, Mo. Why did he choose this controversial topic, one that few vets even acknowledge?
Silver—a pioneer in the field of holistic veterinary medical practice—says he was inspired by a seminar he attended in Boulder on GM foods and human health. The speakers included Don Huber, a Purdue University professor, and activist Jeffrey Smith, who discussed problems, including reproductive difficulties, that have occurred in livestock fed GM crops.
“I found this seminar mind-opening,” says Silver, the lone vet in attendance. “I had always believed the PR about GM foods—that they are going to feed the world and are a good outcome of our genetic technology.”
The Food and Drug Administration, which regulates the safety of GM crops consumed by humans and animals, considers most GM plants “substantially equivalent” to traditional plants and “generally recognized as safe.” Their regulation involves a voluntary consultation process with the developer before products are brought to market.
Smith, founder of the Institute for Responsible Technology, disagrees. On its website (responsibletechnology.org), he warns that “nearly all GM crops are described as ‘pesticide plants.’ They either tolerate doses of weed killer, such as Roundup, or produce an insecticide called Bt-toxin. In both cases, the added toxin—weed killer or bug killer—is found inside the corn or soybeans we consume.”
Silver says that while “allergies, GI problems, increased risk of cancer, neurodegenerative conditions” and other ills could all be, in part, related to GM foods, “there is no objective evidence of this yet” in dogs. “However, all vets will agree that there has been an uptick in [these diseases] in the past 10 to 20 years.” The advent of GM foods in the 1990s “fits into this timing of disease increases,” he says.
His presentation referred to studies that raise doubt about the safety of biotech crops, such as one reported in 1996 in the New England Journal of Medicine, which found that genes inserted into crops can carry with them allergenic properties.
Silver says that genetic modification introduces foreign proteins that may encourage allergies, and the widely planted Bt corn, which makes its own insecticide, “could possibly cause leaky gut, the gateway to chronic disease.” Corn is a major component of most commercial pet foods. “The big problem with commercial foods is that they are manufactured at high temperatures and pressures,” which alters them and makes them “potentially more allergenic.” And commercial foods contain industrial ingredients that are “more likely to contain GM and herbicide contaminants.”
A study published last year found that GM crops engineered to withstand the toxic herbicide Roundup must now be doused with even more herbicide, since weeds have also developed resistance to it. Residues of these chemicals on crops can find their way into pet food.
A 2013 study published in the science journal Entropy reports that the heavy use of Roundup could be linked to Parkinson’s, autism, infertility and cancers. It goes on to report that residues of Roundup in food can interact with, and enhance, the damaging effects of other environmental toxins. “Negative impact on the body is insidious and manifests slowly over time as inflammation damages cellular systems throughout the body,” the study’s researchers say.
According to Silver, heightened sensitivity to dietary ingredients “is probably what we are seeing with GM foods. It is of concern that this may be driving the increase in GI problems in pets.” Although gluten probably does account for some problems with grain consumption, “I think that grain-free diets, if they are also soy free and contain protein from animals not fed GM crops, can help many dogs, due to being GM free—and not due to some allergy or gluten issue.”
To a holistic doctor, food is medicine, and Silver strongly recommends home meal preparation from individually sourced ingredients to avoid feeding GM ingredients, especially to pets who have other health problems. “I am truly a holistic practitioner in that I believe an ounce of prevention is worth a pound of cure.”
References
Carman, J., et al. 2013. A long-term toxicology study on pigs fed combined genetically modified (GM) soy and GM maize diet. Journal of Organic Systems 8 (1): 38–54.
Benbrook, C.M. 2012. Impacts of genetically engineered crops on pesticide use in the U.S.—the first 16 years. Environmental Sciences Europe 24: 24.
Ordlee, J., et al. 1996. Identification of a Brazil-nut allergen in transgenic soybeans. The New England Journal of Medicine 334: 688–692.
Samsel, A., and S. Seneff. 2013. Glyphosate’s suppression of cytochrome P450 enzymes and amino acid biosynthesis by the gut microbiome: Pathways to modern diseases. Entropy 15 (4): 1416–1463.
Good Dog: Studies & Research
Little dogs pee more often on walks
Scent marking is a common form of communication across a wide range of mammals. Although dogs can scent mark in various ways, they most often use urine, which is obvious to anyone who has watched dogs pee here, there and everywhere out on walks or during play time.
Urination, and other forms of scent marking, allow animals to convey a large amount of information in an indirect manner. That means that they can communicate without direct interactions. That has the advantage of avoiding the costs of social interactions, which can include stress, the energetic costs of interacting and potential injury. In many species, body size is closely correlated with competitive ability, which is why scent marking may be especially important to smaller individuals, who may be unlikely to fare well in direct encounters.
Dogs have an enormous size range for a single species, but only recently has the effect of size on frequency of scent marking been investigated. Researchers wondered whether smaller dogs take advantage of the indirect nature of scent marking through urine to be more competitive with larger dogs.
In the recent study, “Scent marking in shelter dogs: Effects of body size”, researchers walked 281 shelter dogs (mostly mixed breeds) that they categorized by size. Small dogs measured 33 cm or less at the withers, large dogs measured 50 cm or more, and medium dogs were above 33 cm but less than 50 cm. They recorded urinations during the first 20 minutes of each walk, noting whether they were directed at a target or not. (Targeted urinations were those that occurred after sniffing a spot on the ground or on some other surface, and those that involved urinating somewhere other than the ground even without sniffing it first.) The study found that smaller dogs marked more often than medium or large dogs and that they were more likely to direct their urine at targets compared to large dogs. Though smaller bladder capacities of smaller dogs could explain increased frequency of urination, that cannot account for the increased frequency of urinating on targets.
As expected, males also marked more frequently and directed their urine at targets more often than female dogs did. The length of time that dogs had spent in the shelter was positively associated with frequency of directed urinations, but not with total number of urinations. Size had no effect on the frequency of defecations on walks, but dogs who had been at the shelter longer were a little bit more likely to defecate on walks.
The authors concluded that smaller dogs use scent marking in the form of urination more frequently that medium or large dogs. It is possible that they are using scent marks in order to avoid direct interactions.
Good Dog: Studies & Research
Scientific study into the cues causing dogs’ reactions
“Fighting like cats and dogs” is an expression that succinctly describes the worst case scenario of dog and cat interactions. Not all dogs and cats have to get along with each other to live full and happy lives, but it sure is important to know which dogs can live with cats and which ones can’t. That’s especially critical for shelters seeking to find homes for dogs, because nobody wants to adopt a dog who will terrorize their cat. Though there are many ways that shelter staff can evaluate a dog’s response to other dogs and to people, there is far less information, and no validated assessment tool, for evaluating how a dog will react to cats. In most cases, we don’t even know what it is about a cat that sets dogs off, other than the useless knowledge that the dog is reacting because the cat is a cat.
A recent study seeks to change that by adding to what we know about which triggers from cats set dogs off. “Dogs’ responses to visual, auditory, and olfactory cat-related cues” concludes that the sound of a cat and how a dog reacts to it may be of critical importance when evaluating dogs. In the study, dogs reacted more to the auditory stimuli of cats than to visual stimuli of cats, but the stimuli they used were not directly comparable.
The visual stimulus was an animatronic children’s toy, the auditory stimulus was a recording of cat vocalizations, and the olfactory stimulus was cat urine. Because only the auditory stimulus was the actual stimulus that a dog would perceive in the presence of a cat, it is hard to accept the conclusions of the study. The actual odor of a cat and the sight of a live cat are different than the stimuli presented in the study.
The researchers found that dogs who had previously hurt a cat were more attentive to the auditory stimuli than other dogs were, though there was no difference in the behavior of dogs in either group towards the visual cat stimulus. The olfactory stimulus was associated with dogs spending more time sniffing than when no olfactory cue was present.
Responses to cat sounds could be a useful predictor of whether or not a dog will get along with cats, but more research is necessary. (It would be of particular importance in future studies to consider the stimuli presented during assessments.) The results of this study could also be explained by concluding that dogs attend more to realistic cat stimuli and that dogs who have previously hurt a cat are especially attentive to realistic cat cues, which in this study only applied to the auditory cue.
Good Dog: Studies & Research
A study of the Delboeuf illusion
Visual illusions reveal the inner working of the eyes and of the brain, and when used in comparative studies, they can teach us a lot about the differences and similarities in vision and neurological processing between species. A common research approach involves using illusions that affect perception of size and investigating whether the illusions affect choice. Allowing research subjects to choose between various options can elucidate the illusions’ effects on members of various species.
One such illusion is the Delboeuf illusion, which causes identically sized objects to appear different in size depending on what surrounds them. In the image below with dark circles of identical size, humans (and other primates) tend to overestimate the size of the circle on the left, which is surrounded by a ring that is smaller than the ring around the circle on the right.
In practice, this is the reason that people seeking to eat smaller portions of food are advised to use a smaller plate. That makes it appear as though there is more food on that plate than when the same portion is served on a larger plate. Can dogs who are watching their figures make use of this same tactic? In other words, are dogs also susceptible to the Delboeuf illusion? The answer is no, according to a study in Animal Cognition called “Do domestic dogs (Canis lupus familiaris) perceive the Delboeuf illusion?”
In the study, one set of trials tested whether dogs could correctly choose larger portions of food over smaller ones. Dogs were given a choice between two piles of biscuits on plates—one pile of biscuits weighed 18 grams and the other weighed 32 grams. Once dogs chose to go for one plate, the other one was picked up and no longer available. Sometimes both portions of food were on small plates, and sometimes both were on big plates. Each dog was offered this choice multiple times. Pooling the date into one big analysis, dogs consistently chose the bigger pile of biscuits.
In another series of trials, dogs were offered a choice between equal portions of food that were presented on different size plates. The dogs had to choose between 32 grams of food on a large plate and 32 grams of food on a small plate. If dogs are susceptible to the Delboeuf illusion, the expectation is that they would choose the smaller plate even though the quantity of food was identical on both plates. Instead, dogs’ choices were no different than if they picked a plate at random with no reference to its size. They were not significantly more likely to choose the large plate or the small plate, providing evidence that the Delboeuf illusion does not affect dogs the way that it affects humans. Dogs are not fooled by the size of the plate.
Good Dog: Studies & Research
Studies on dogs following gestures.
AT TWO WEDDINGS, darling ring bearers paraded down the aisle proudly holding the prized objects. They couldn’t have been more than six. When they suddenly stopped—as six-year-olds tend to do—to look at something on the ground, guests leaned into the aisle and pointed toward the beaming faces ahead. Smiles filled the crowd as they continued on their way.
At one wedding, the ring bearer was a little boy, and at the other, a dog.
If we’ve spent any time with companion dogs, we aren’t surprised when a dog stops to check out the ground. It also shouldn’t surprise us that a dog might go where we point. Pointing is about social communication, and it often feels like dogs are right there with us, sometimes even more than members of our own species.
In the last 20 years, dogs’ attention to our communicative gestures—particularly this thing we do with our arm and finger—has attracted enormous attention from researchers around the globe. In fact, the pointing gesture is so fundamental that seemingly no article on the canine mind is complete without a sentence such as “dogs read our gestures, like pointing, more flexibly than any other animal” (New York Times), or—more boldly in Time—“While chimps and even wolves lack an innate ability to understand what pointing means, dogs come by the knowledge naturally.”
These statements tend to produce any number of reactions in dog owners, from “Obviously,” sometimes accompanied with a side of, “Why do they bother to do this research anyway?” to the flip side: “My dog doesn’t do that … what are they talking about?” Or even the more nihilistic view: “Sure they do, but who cares?”
Here’s why we care: this one little gesture, in all its complexity, could be a core feature of the intimate bond we share with dogs.
Since the late 1990s, researchers have tried to uncover why and how dogs pick up on our cues. Initially, key questions focused on whether their ability to follow the pointing gesture arose from our long-standing co-evolutionary history or, alternatively, if they learned the behavior over the course of their individual lives.
Pointing Is About Us
Pointing is something we humans do as part of our social communication, and it is useful only because we all agree on how it should be interpreted. Imagine if your point were perceived as, “Hey! Check out my fingertip. No dirt under my nail. Wonderful, huh?” Not exactly useful for communication. Fortunately, we understand that pointing creates a shared experience beyond our fingertips; pointing draws someone’s attention past our outstretched index finger to something out there in the world.
This cooperative gesture serves us well. Yelling, “Look out!” is only somewhat informative, but yelling, “Look out!” and pointing can help a fellow human locate and respond to a Frisbee sailing in at head level or Godzilla rampaging down Fifth Avenue. Communication achieved.
Despite our mothers’ reminders that pointing is rude, it has a function: it reflects our ability to hold shared attention with others, which could also indicate that someone else is aware of the same thing that we are. Pretty meta. Joint attention can thus be associated with an ability to infer others’ mental states, which is considered an important social capability in humans.
At about six months, children start following the gaze and gestures of others. We start pointing around our first birthday and become increasingly point-savvy as we age. When toddlers see something of interest and point at it, they become excited when we also look. They will also point when seeking something or to provide information (I want that. You dropped something). Regardless of how it’s used or understood at any given age or moment, pointing intrinsically aids our communication with one another.
Do Dogs Get the Point?
It shouldn’t come as a surprise that much of the academic interest in the canine mind that blossomed in the late 1990s was actually largely about us, investigating to what extent dogs responded to our communicative gestures— notably, our pointing. In research labs around the world, it has been a pointing party ever since.
Watch any program covering research into the canine mind and you’re bound to hear mention of studies involving a dog, two cups and a pointing human. The experiment, commonly referred to as the object-choice task, follows some variation of this procedure: a dog first learns he can get a treat for approaching either of two identical cups. He then watches as a person points to one of the cups. Will the dog follow the point to the cup?
Human children are quite good at this task, and numerous studies confirm that dogs are, too. From an early age, dogs are highly responsive to this gesture. Dogs do well when a person points with a foot, or bows or nods. They’ll also respond to what’s commonly referred to as a “momentary” point, in which the person points and then lowers his or her arm before the dog makes a choice. They will follow the point even when a person stands by one cup and points at the other. Although we all know smell is a major player in the canine world, it doesn’t appear to factor greatly into dog performance; when food is hidden under one cup and nobody points, they don’t do so well. Some researchers describe their performance as “remarkable” and “outstandingly flexible.”
Not all species catch our communicative drift. A bee that flies into your car will never be aided by your outstretched arm pointing toward the open window. Given dogs’ long history with us, researchers wondered whether canine sensitivity arose through the domestication process—in which case, wolves, their closest relative, might be less adept in this task—or, on the other hand, whether it’s a product of learning and dogs’ individual life experiences. Or maybe the reality is not so black-and- white. What underlies their highly flexible ability?
Wolves do not follow our gestures as flexibly as dogs. Nor do chimpanzees, our closest relatives. This isn’t to say that wolves (or chimpanzees) can’t or don’t do it. Extensively socialized wolves and enculturated chimps—those highly familiarized with human behavior— can follow our points, but dogs generally respond more readily and easily, and wolves need more exposure to perform similarly. In 2002, Brian Hare of the Duke Canine Cognition Center pulled together then-current research on dogs, wolves and chimpanzees and, in an article in Science, concluded, “Dogs’ social-communicative skills with humans were acquired during the process of domestication.”
Both Nature & Nurture Point to Success
More immediate genetic influences, like artificial selection, could also influence dogs’ skills. Márta Gácsi and colleagues at the Family Dog Project in Budapest found that while all dogs tested followed the point better than chance would predict, dogs bred for cooperative work (like gun dogs) performed better than those bred for independent work (like guard dogs). All the dogs in the study were living as pets and none had received special training, implying that genetics plays a role at some level in enhancing dogs’ ability to follow our gestures.
At the same time, individual life experiences could also contribute to a dog’s responsiveness. For example, the reactions of shelter dogs to our pointing gestures vary widely, and a small group of intensively socialized lab-raised dogs did not fare well in the task.
Lucia Lazarowski of the Comparative Cognition Laboratory at Auburn University, one of the investigators in the lab-raised dog study, saw their challenges first-hand. But when she later adopted Captain, a study participant, and informally examined his responsiveness to pointing, she found he performed much better in her home: “He actually looked in the direction I pointed and sniffed in the area I was pointing to. During the test, however, he was one of the more non-responsive dogs. Now, we like to play a game where I toss small treats around the room for him to hunt, and if he can’t find them, sometimes I’ll point to them, so he probably has picked it up from that.” Captain’s transition to canine pointfollower highlights that learning and life experiences can factor into the skill.
The person behind the point can also affect dog performance. Amy Cook, CDBC, CPDT-KA, conducted a study on the topic at the University of California, Berkeley; reporting in Animal Cognition, Cook noted that when owners and strangers were pitted against one another (in what I hope was described as a “point-off”), dogs tended to follow their owners, even when they received no reward (i.e., the point did not lead to the dog getting food). As Cook explains, “Dogs make decisions by attending preferentially to social signals from humans with whom they have become more familiar.” Many of us think it’s all about us, and our dogs might agree.
If dogs respond to the pointing gesture based on whose finger is doing the work, then again, it looks like life experiences could be controlling the switches. But not so fast: Cook suggests that this unique spin on the issue— dogs being more attentive to a familiar person—could have been shaped by evolutionary pressures to bond with a caretaker. Attachment relationships between dogs and their humans are well documented and, as Cook says, going with your person could be “a successful strategy in the long term.”
Isn’t it nice when everyone can be right? Dog responsiveness to our communicative gestures could be a product of their evolutionary history plus their ability to learn rapidly once in a human environment. In a 2009 article in Behavioural Processes, Pamela Reid, CAAB and vice president of the ASPCA’s Anti-Cruelty Behavior Team, reflects on what’s behind canine responsiveness to our social cues: “Dogs are too skilled for it to be pure trial-and- error learning. Yet it is improbable that a versatile behavior like this would be largely innate.” She suggests that what we see in dogs is an adaptive specialization of learning. “In essence, they come with a built-in head start to learn the significance of people’s gestures, in much the same way that white-crowned sparrows acquire their species-typical song and ducklings imprint on their own kind.” This fits in well with what is understood of instinctual or innate behaviors. As Jack Hailman explained in his inf luential piece in Scientific American in 1969, “How an Instinct Is Learned,” species-specific behaviors require some amount of experience and development.
When Patricia McConnell, CAAB, mulled over the pointing research on her blog, “The Other End of the Leash,” she agreed that dogs could be “predisposed to learn to follow a pointing gesture.” McConnell also highlights something you might have seen yourself: present a very young puppy with an outstretched finger and that puppy is going to approach your fingertip, not follow it to a distant location. McConnell’s point is that point-following in puppies is not automatic, although they learn it very easily.
To this, Reid adds, “Just because a skill appears early in development does not preclude learning. It does, however, demand that puppies be highly attentive to the actions of humans, a tendency that has been confirmed in studies of dog-human attachment.”
What Do You Understand, Dog?
What do dogs think of all this? What does it mean to be a dog who “understands” our pointing gesture?
A 2013 article by Ádám Miklósi and József Topál of the Family Dog Project in Trends in Cognitive Sciences concludes by highlighting that “dog social competence [appears] sometimes ‘infant-like’ or ‘human-like,’ but, importantly, the underlying mental mechanisms may turn out to be quite different.”
It’s hard enough for us to figure out if, for example, our boss is merely suggesting that we do something or telling us to do it. The same is true for dogs and the pointing gesture. Do dogs see pointing as an imperative—“You. Go there.”—or as simply providing information or a helpful suggestion—“I recommend that you go there.”—a subtle yet meaningful difference. A 2011 article published in Applied Animal Behaviour Science by Helene Pettersson and colleagues found that, like children, dogs are more likely to follow a point when it is accompanied by a cooperative tone of voice as opposed to a prohibitive tone. At the same time, dogs sometimes follow the point to an empty container, leading some to wonder whether, under certain circumstances, dogs might perceive the gesture as a command.
Like humans, dogs seem to distinguish when communication is—or is not—intended for them, although they could be relying on a more limited set of cues. Numerous studies find that initiating eye contact and using high-pitched vocalizations help dogs understand that the communication is for them. Setting is also important. In a 2011 study reported in PLoS ONE, Linda Scheider and colleagues found that if a person points to a location where a dog has never experienced reinforcement, the dog is not as likely to follow as he would be if he had previously received reinforcement there (making me wonder whether the ring-bearer dog would spontaneously follow the point to the altar).
At some level, every pointing gesture suffers from a fundamental ambiguity: we might be pointing to a particular object, or we might be pointing to a specific space that happens to be inhabited by a particular object. Usually, we can figure it out without too much cognitive difficulty. Even nine-monthold infants understand when pointing refers to an object as opposed to the place where the object is located.
How about dogs? In a study recently published in the Journal of Comparative Psychology by Tibor Tauzin and colleagues, an experimenter pointed at one of two different toys on either side of him. Before the dog could approach, the experimenter switched the location of the objects in full view of the dog. The researchers wondered whether the dog would approach the object that had initially been pointed at but that was now in a new location, or to the original location of the point. The result? Dogs did not follow the object to its new location. Instead, they approached the old location, which seems to imply that, for the dog, pointing could be more about the location than the pointed-at object.
For those of us who live or work with dogs, much of the value of pointing studies lies in what we do with the results. Despite being unflashy, the pointing gesture is actually rich in dimensions and angles that we can explore with our dogs. As Reid recommends, “Take note of your body gestures. Does your dog attend to your gestures in all cases, or only in certain contexts? Dogs are often way more sensitive than we can grasp. They’re not trying to fool you or trick you, get one over on you or cheat the system. Attending to our gestures is just what dogs do. It’s who they are.”
References
Cook, A., et al. 2014. My owner right or wrong: the effect of familiarity on the domestic dog’s behavior in a food-choice task. Animal Cognition 17: 461–470.
Franco, F., and G. Butterworth. 1996. Pointing and social awareness: declaring and requesting in the second year. Journal of Child Language 12(2): 307–336.
Gácsi, M., et al. 2009. Effect of selection for cooperation and attention in dogs. Behavioral and Brain Functions 5:31.
Hailman, J.P. 1969. How an Instinct Is Learned. Scientific American 221(6): 98–106.
Hare, B., et al. 2002. The domestication of social cognition in dogs. Science 298(5598): 1634–1636.
Hochman, D. 2014. You’ll Go Far, My Pet. New York Times, April 11.
Kaminski, J., et al. 2011. How dogs know when communication is intended for them. Developmental Science 15: 222–232.
——— and J. Nitzschner. 2013. Do dogs get the point? A review of dog-human communication ability. Learning and Motivation 44(4): 294–302.
Lazarowski, L., and D.C. Dorman. 2015. A comparison of pet and purpose-bred research dog (Canis familiaris) performance on human-guided object-choice tasks.[1] Behavioural Processes 110: 60–67.
Miklósi, A., and J. Topál. 2013. What does it take to become ‘best friends’? Evolutionary changes in canine social competence. Trends in Cognitive Sciences 17(6): 287–294.
Pettersson, H., et al. 2011. Understanding of human communicative motives in domestic dogs. Applied Animal Behaviour Science 133(3-4): 235–245.
Reid, P. 2009. Adapting to the human world: Dog’s responsiveness to our social cues. Behavioural Processes 80(3): 325–333.
Scaife, M., and J.S. Bruner. 1975. The capacity for joint visual attention in the infant. Nature 253: 265–266.
Scheider, L., et al. 2011. Domestic dogs use contextual information and tone of voice when following a human pointing gesture. PLoS ONE 6(7): e21676.
———, et al. 2013. Do domestic dogs interpret pointing as a command? Animal Cognition 16: 361–372.
Tauzin, T., et al. 2015. What or where? The meaning of referential human pointing for dogs (Canis familiaris). Journal of Comparative Psychology 129(4): 334–348.
Udell, M., et al. 2008. Wolves outperform dogs in following human social cues. Animal Behaviour 76: 1767–1773.
Zimmer, C. 2009. The Secrets Inside Your Dog’s Mind. Time, September 21.
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