Good Dog: Studies & Research
Dogs’ Color Vision
When Maureen and Jay Neitz adopted an adorable, fluffy black puppy in the late 1980s, they had no idea how important she would be in making new discoveries about vision.
They were just looking for a dog who was size-appropriate for the small apartment they lived in as UC Santa Barbara PhD candidates. Eventually, the teacup Poodle they named “Retina” helped the couple prove that dogs see much more than just black and white, and that dogs’ color vision is similar to that of the 8 percent of the human population who are red-green colorblind.
Ten million Americans, most of them male, are affected with red-green colorblindness, a genetic trait carried on the X chromosome. People with this condition can’t clearly see the difference between red and green. They often mistake green for white and red for brown or dark gray.
Colorblindness might not seem like a serious disability, but it causes unexpected, and sometimes tragic, problems for humans. For example, airline pilots must be able to differentiate between colors, which someone with red-green colorblindness can’t reliably do. Color vision is, of course, crucial in being able to discern if a traffic light is red or green. According to Don Peters, a consultant to the biotech industry who has red/green colorblindness, “Sodium vapor lights look a lot like red stoplights to me. It’s confusing to drive in an area with these lights, especially at night.” As a child, he had difficulties with color-related tasks: “I can still hear my teacher asking me why I colored the tree red. I couldn’t tell the difference.”
Colorblind people miss a lot of detail that people with normal color vision take for granted: they might not see the lines on a map, or lettering printed in colors that seem bright to those with normal vision but blend in for them. This can be dangerous when reading traffic signs or medication labels. Jay Neitz pointed out that children who are colorblind often have trouble in school, and can be mistakenly diagnosed with learning disabilities or ADHD; in spite of these potential problems, schools do not test students’ color vision.
The Neitzes established that dogs see shades of yellow, blue and gray. Other colors, such as red and green, appear faded or indistinct. Jay Neitz had an “aha” moment when Retina could not find her orange ball in a green lawn. “Sometimes the ball was right in front of her, but she would sniff around in the grass, trying to find it by smell. We realized that she simply couldn’t see it, even though it was obvious to us,” he said.
As UC Santa Barbara post-docs with degrees in biochemistry, molecular biology and biopsychology, the couple had access to a lab in which they could set up a testing area. “I realized that I had the opportunity to find out, once and for all, what kind of color vision dogs really have.” Jay built an apparatus that placed dogs in front of a screen with three lit panels. He trained the dogs to touch the screen with their noses when they saw a different shade. If the dog got it right, she would receive a cheese-flavored dog treat. In order to get the dog to touch the screen, Jay used peanut butter as an incentive. Once the dog mastered that part of the test, Jay no longer used the peanut butter.
Right away, Maureen and Jay discovered that, like people, dogs were good at figuring out shortcuts to getting a treat. In addition, “About 30 percent of the time, the dog made a lucky guess,” according to Maureen. The dogs’ attention spans were short, and on more than a few days, they just didn’t feel like doing the tests. “It took six months per dog to train them,” Maureen said. In addition to Retina, the Neitzes used two Italian Greyhounds; like Poodles, they are small, intelligent, easily trained dogs. “The dogs were treated very well,” Maureen said. “We had the utmost concern for their welfare.”
In 1989, Jay Neitz co-authored “Color vision in the dog,” which was published in the journal Visual Neuroscience; the research paper confirmed that dogs do, indeed see more than black and white. That led to a years-long search for a cure for colorblindness in humans.
Along the way, Jay heard from a diverse group of people interested in animal color vision. Game wardens asked him to create a color that hunters could use to spot each other but would be invisible to deer (“blaze orange” was the result) and, more recently, hundreds of people wanted to know what he thought of “The Dress,” a photo that went viral on the Internet featuring a dress that looked white and gold to some, blue and black to others.
Even the U.S. Army expressed an interest in the couple’s research. “They wanted to know if we could give dogs infrared vision so they could see lights used in locating bombs without alerting the enemy.” Jay joked that more people than he can count have sent him the “Far Side” cartoon showing a dog praying next to a bed, with a caption that reads “And please let Mom, Dad, Rex, Ginger, Tucker, me and all the rest of the family see color.”
Today, the Neitzes are both professors of ophthalmology and color vision researchers at the University of Washington. They continue their work in the field of color vision, but they don’t use dogs anymore. “Our dog study was done purely out of curiosity,” Maureen said. Jay added, “We demonstrated that color vision is much more complex than previously known, both in animals and in humans. Somewhere in our evolutionary past, humans developed the ability to see colors, which has helped us in many ways. One important advantage to having color vision is that it helps us determine whether a piece of food is ripe, and therefore good to eat. Humans were able to spot high-calorie food without putting out too much effort.”
In 2009, the Neitzes cured colorblindness in several male squirrel monkeys using gene therapy.
According to Maureen, “Male squirrel monkeys see only blue and yellow. Therefore, they make good subjects for color vision research.” The tests that the Neitzes developed during their original study with Retina and the two Greyhounds are now “vastly improved. We use a version of the Cambridge color test intended for human color vision testing, which Jay adapted so that it can be used on animals. It uses 16 colors, all of varying saturations.”
This more accurate test helps speed up color-vision research. The monkeys were given a human gene, which allowed them to see color the way we do. According to an article in Science, “The result raises questions about how the brain understands color, and it could eventually lead to gene-therapy treatments for colorblindness and other visual disorders in humans.”
As the Neitzes get closer to giving colorblind people normal color vision, it’s inspiring to think that a teacup Poodle trying to find her ball in the grass helped make this possible.
Read more about the Neitzes’ work.
Good Dog: Studies & Research
My dog Millie, a five-pound Yorkshire Terrier, and I do almost everything together. We hike, camp, watch sporting events, grocery shop, spend all day at the bookstore and visit research labs. Everywhere we go, people are attracted to her; they want to hold her, pet her or just say hi. Why do so many people think she is so cute? Is she perceived as cute because of her looks or her behavior? As it turns out, cuteness is influenced by both physical attributes and behavior, factors that affect the perception of cuteness in a variety of animal species.
Like many infant animals, babies and puppies have several things in common: large heads, round faces, big eyes. These appealing traits have a name: Kindchenschema (baby schema). A concept introduced by Konrad Lorenz in 1942, baby schema is defined as “a set of infantile physical characteristics ... [that] motivates caretaking behavior in other individuals, with the evolutionary function of enhancing offspring survival.”
Research by Kringelbach and others suggests that this baby schema may extend beyond physical characteristics to include “positive infant sounds and smells.” It’s not hard to imagine that these findings could also be applicable to puppy whimpering and barking, and that unmistakable puppy odor.
A preference for baby schema occurs early in human development. In a study by Borgi et al. (2014), researchers used eye tracking to determine that both children and adults looked longer at pictures rated high in infantile characteristics than at those rated low. This held true for pictures of humans, cats and dogs. And as research by Dekay and McClelland has shown, humans like animals who appear more humanlike; our concern for the well-being of a species correlates strongly with the species’ similarity to ourselves.
This partially explains why pet owners have a tendency to anthropomorphize their companion animals. I often talk to Millie as though she can understand every word, and I put her in her bed and arrange everything for her comfort much as I did for my son when he was small. Some persist in treating their dogs like children even when it clearly aggravates the dog. Although it might not bother all dogs, most dogs you see wearing cute clothing and bows in their hair would probably prefer no clothing or no bows. (When groomers put a bow on Millie, she has a fit and usually manages to remove it on the car ride home.)
Behaviors such as hand shaking, rolling over, speaking on command or engaging in unusual tricks also influence our perception of a dog’s cuteness. Conversely, specific behaviors can also detract from a dog’s cuteness quota. Excessive barking, aggression or chewing everything in sight tends to diminish our perception of exactly how cute a dog is.
This biological hardwiring has an evolutionary advantage. The human response to cuteness includes protective behavior, a willingness to care for the animal and increased attention, all things that can be good for the dog. Initially, I became interested in cuteness and its influence on humans after talking with a researcher at Eastern Kentucky University who studies perception. His work focuses on the affect of canine head tilt on a dog’s “cuteness” rating. One of the things he’s found is that the same dog can receive different ratings depending on the degree of tilt.
This type of research has direct application to the dog adoption process. As mentioned, cuteness induces protective behavior, which often leads to positive human-dog interactions. It follows that these feelings may result in a decision to adopt the dog who elicits them and to overlook those who don’t.
Because the well being of dogs is heavily dependent on their relationships with humans, it’s important to understand that these often-unconscious biases affect our choices. There’s nothing wrong with loving a cute dog—as I do Millie—but dogs of all sorts need love, and their value should not be determined by how cute we think they are.
Good Dog: Studies & Research
How Closely Are They Linked?
I’m interviewing a new client whose dog tends to bark and charge and nip the heels and dan- gling hands of retreating strangers. Her dog is smallish and stocky, with a coarse, medium-length coat of mottled blue-gray, black, white and brown. His nose and ears are pointy. While I reassure her that his behavior actually makes sense from his doggy point of view, a little voice in my head whispers, “What did she expect? She got a Cattle Dog.” I have little difficulty discounting the client’s own plaintive claim that she’s had Cattle Dogs all her life and this is the first one who’s acted this way. “You were lucky until now,” my little voice says, assuming those dogs were somehow the exceptions. But when another client complains that his large, square-headed, short-coated, yellow dog is growly around his food bowl, I take his statement that “none of my other Labs have done this,” at face value. The current dog is clearly the exception. After all, my little voice says, “everyone knows Labs love people.”
My little voice is probably wrong.
So why not use breed as the way to choose the particular puppy or dog who’s likely to help us fulfill the dream of taking a perfectly behaved, friendly dog to cheer the lives of people in nursing homes, be endlessly tolerant with our kids or have the kind of indefatigable enthusiasm for retrieving that makes a good contraband-sniffing dog? How about using breed stereotypes to guide public policy decisions on whether some dogs are more likely than others to present a danger to people, or simply to assess whether that dog coming toward us means us good or ill?
Turns out it’s not that simple.
And even reliable identification of the ancestry of a mixed-breed dog by itself wouldn’t help us predict an increased likelihood of known, genetically driven traits — say, the blood-clotting disorder that plagues Dobermans or the heart defects of Cavaliers. The parents of any mixed-breed dog have, by definition, waded out of the closed gene pool that makes purebred dogs such fertile ground for genetic research. The inevitable inbreeding of purebred populations, combined with a phenomenon called genetic drift, gradually decreases overall genetic diversity; more and more animals have fewer and fewer variable traits, including characteristics that aren’t deliberately selected for or against. But as researchers found with a colony of wolves in Sweden, even inbreeding so severe that it causes infertility can be reversed by the introduction of just one outsider. So, if we could demonstrate such a thing as “acting like a Beagle” or “acting like a Basenji,” there would be little reason to expect either one from the offspring of a Beagle/Basenji pairing.
But what about those purebred Basenjis and Beagles and Cattle Dogs and Afghans and Golden Retrievers? Can’t we expect them to behave consistently in ways that resemble the work at which they were once selected to excel?
Yes and no.
And yet, every single one of her ancestors, going back scores, perhaps even hundreds, of generations, was hyper-motivated to chase. They would not have had the opportunity to reproduce otherwise. Racing Greyhounds are bred for two things only: a keen inclination to pursue small, fast-moving furry things and the physical ability to do it at great speed. Racing industry insiders estimate that only about 70 to 80 percent of the dogs who result from this ruthless selection process are keen enough to race. Now, a 75 percent incidence of a trait sounds pretty high. You’d certainly take those odds in Vegas at the roulette wheel. But this is a trait that’s already extremely common across the species; it is, in all likelihood, the most widespread of the predation behaviors of hunting, stalking, chasing, killing, dissecting and eating first observed and described by the famous wolf ethologist, David Mech. Most dogs already do this. If you take more complex behaviors that are actually selected against in the wild, like compulsively fighting other dogs and failing to respond to the doggy body language equivalent of “crying uncle,” for example, your odds of reliably producing the behavior through artificial selection go down dramatically. This explains how so many of the so-called “game-bred” dogs from fight busts (like the ones rescued from Michael Vick’s fighting operation) have gone on to live companionably with other dogs as relative couch potatoes in normal homes.
Reliably increasing the likelihood of complex behaviors through selective breeding isn’t easy. And racing Greyhounds are one of only a handful of dog breeds where this is still even attempted. Since the advent of modern purebreds in the late 19th century and the subsequent closing of breed registries, selection criteria have focused almost exclusively on appearance. Qualities of temperament are sometimes mentioned, although not in ways that can be practically applied in the show ring, where — as biologist Ray Coppinger has pointed out — the behavior required is standing, and to a lesser degree, trotting alongside a handler. Most purebred dogs come out of this selection system.
So these days, when people look fondly at the breed they fancy or angrily at the one they fear and say to me, “They’re not like other dogs,” I remind my little voice to recite, “Well, actually, they kind of are.”
Good Dog: Studies & Research
A new approach allows further study
The influence of genes on personality and behavior is of great interest to people who love dogs as well as to scientists studying the genetics of animal behavior. Since dogs’ personalities play a major role in their ability to function as our companions as well as to carry out a variety of tasks as working dogs, it’s important to understand the contribution of genetics on behavior. It is well established that genetics plays a large role, as evidenced by behavioral differences between breeds. Even substantial differences in behavior within breeds can be accounted for by genetic variation.
One of the challenges to studying behavioral genetics is that large sample sizes are required because there are so many factors that influence behavior (e.g. early environment, training methods, various lifestyle factors). To achieve adequately large sample sizes in research is both expensive and time consuming, sometimes prohibitively so. A recent study called “Genetic Characterization of Dog Personality Traits” took a creative approach to meet this challenge.
The scientists were interested in genetic contributions to personality, defined as “individual consistency in behavioral responsiveness to stimuli and situations”. Researchers took advantage of the substantial knowledge people have about their own dogs’ personalities to explore genetic contributions to personality traits. Their work shows that it is possible to detect genetic variation in dog personality traits by using questionnaires to collect large quantities of useful data.
In this recent study, researchers used the C-BARQ (Canine Behavioral Assessment Research and Questionnaire) as well as a separate questionnaire about demographics to study 1975 UK Kennel Club-registered Labrador Retrievers. The C-BARQ allowed each dog to be scored for the following personality traits—Agitated When Ignored, Attention-Seeking, Barking Tendency, Excitability, Fetching, Fear of Humans and Objects, Fear of Noises, Non-Owner Directed Aggression, Owner-Directed Aggression, Separation Anxiety, Trainability and Unusual Behavior.
The additional questionnaire collected data about the dog’s age, coat color, sex, neuter status, housing, health status, exercise, daily exercise and the role of the dog. (The various roles were gun dog, show dog and pet dog.) To gather genetic information, the study took advantage of the dogs’ pedigrees, which involved 29 generations and 28,943 dogs. Further genetic data on the dogs were obtained as part of a different study using standard genomic methods and genetic markers, with 885 dogs from that study also participating in the C-BARQ portion of the research. In the analysis, the researchers estimated heritability of personality traits based on both the pedigree and on the genomic data.
The researchers found that fetching has a higher heritability rating than any other personality trait. Interestingly, some previous studies have lumped trainability with fetching ability, which results in lower heritability scores for both of them. This study also revealed a considerable genetic component to the fear of noises. Aggression directed towards owners showed no genetic component at all, while aggression towards strangers had a moderate genetic component.
Many behavioral traits are polygenic (influenced by a large number of genes, with each one often having a small effect) and also have significant environmental influences, which means that it is difficult to determine genomic associations. Estimates of heritability are likely to increase with technological advances in genetic work.
The importance of this study is that it shows that genetic variance can be detected and studied with the use of questionnaires filled out by owners. It also reveals that grouping responses into behavioral factors may make it harder to detect the genetic influence on various traits.
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.”
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.
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