Dog's Life: Lifestyle
More evidence that dogs attend to human emotions
Science is subject to trendiness, just like fashion, language and entertainment are. So, just as we are all facing an abundance of mid-calf boots, abbreviations and post-apocalyptic films, there is no shortage of studies on the influence of human emotions on our dogs. One of the latest studies, Fetching what the owner prefers? Dogs recognize disgust and happiness in human behaviour, in the journal Animal Cognition, is just one of many recent works to explore this topic.
The purpose of this study was to address two questions: 1) Can dogs discriminate between human expressions that indicate happiness, disgust, and neutrality? 2) Do dogs prefer objects eliciting the more positive human emotion in the owner?
In this experiment, dogs had to choose between two bottles, each of which was associated with a human emotional expression of happiness, one of disgust or a neutral expression. The bottle associated with a more positive expression had food inside it while the other one contained a stone. (Though this is potentially a problem in the experimental design—the objects are not identical, meaning that the contents of the bottle as well as the guardian’s expression could be influencing the dog’s decision—the researchers conducted some control trials in an attempt to eliminate this potential glitch.)
The researchers measured dogs’ choices in two ways. They recorded which bottle the dog approached first and which they retrieved. They argued that positive emotions in humans may be linked with a corresponding emotion in the dog because what people feel positively towards—going for a walk, starting to play or dinnertime—may also trigger positive feelings in the dog. On the other hand, negative emotions in people may not correspond to the dog’s response to something. That is, when humans express disgust, it may be related to objects that dogs find appealing such as trash or poop. That’s why, in this study, the experimenters looked at a task (fetching) rather than just an approach to an object. They wanted to see how dogs responded to human requests rather than simply making a choice based on their own preference. The goal was to get a better measure of dogs’ responses to human emotions.
The overall findings of this study are that yes, just like in so many other studies recently, dogs are attuned to the emotions of their guardians. They preferentially retrieve the object associated with a more positive human emotion. So, when their guardian expressed happiness over one bottle and disgust or neutrality over the other bottle, they were significantly more likely to retrieve the bottle associated with happiness. Similarly, if their guardian expressed disgust over one bottle but was emotionally neutral about the other, the dog was more likely to retrieve the neutral bottle.
What I find most interesting in this study is that dogs preferentially retrieved the object associated with a more positive emotion even though they didn’t necessarily show a preference when measured as first approach. In other words, they acted according to human preference when told to do something—“Fetch!”— even though it was sometimes in contrast to their preference about which object to approach. We all know that dogs find many things appealing that revolt us. I’m personally thinking of how often I had to bathe my dog after he rolled in fox poop when I lived on a farm. I found it disgusting but it was clearly very appealing to him even with the threat of a bath hanging in the balance.
If the researchers had only looked at approach, they might have concluded that dogs could not discriminate between the various human expressions of emotion. Their more complex design provides evidence that dogs can do so, but that they don’t always behave accordingly.
Dog's Life: Lifestyle
Dogs affected by state of their guardians
Emotional contagion is the trigger of an emotional response due to perceiving a similar emotional state in another individual. Emotional contagion has been studied extensively in birds, primates and dogs, among other animals. It is generally more pronounced between individuals who know each other than between strangers.
Emotional contagion occur between dogs and people. There is evidence that dogs are sensitive to their guardians’ emotions and that dogs’ behavior is influenced by the emotional expression of those guardians. It has been suggested that dogs have “affective empathy” towards people. That is, dogs can actually feel the emotional experiences of humans, including stress.
Stress has an interesting influence on memory in both humans and non-humans. The effect of stress on memory follows an inverted U-shaped curve. This means that as stress goes up to moderate levels, tasks that rely on memory improve, but as stress increases further, memory tasks are impaired.
In the recent study Emotional contagion in dogs as measured by change in cognitive task performance published in the journal Applied Animal Behaviour Science, researchers investigated the role of stress and emotional contagion between dogs and people on performance in memory-related tasks.
Each dog was randomly assigned to one of three groups—stressed guardian, non-stressed guardian or stressed dog. The direct manipulation of canine stress levels allowed researchers to compare whether stress by emotional contagion had a similar affect as direct stress on the dogs’ performances. Dogs’ stress levels were increased by briefly separating them from their guardians.
Researchers experimentally manipulated the anxiety levels of people and then recorded their responses to a word list memory task. Stress levels were manipulated by giving the person mainly positive or mostly negative feedback during the experiment. Researchers recorded changes in dogs’ responses to memory tasks after guardians were stressed or not stressed as well as after directly manipulating dogs’ stress levels.
Stressed guardians performed better in the memory task than non-stressed guardians. Dogs improved their performance on memory tasks after they were stressed and after their guardians were stressed. Dogs in the non-stressed guardian group showed no such improvement. This study shows that guardian anxiety affects by and has a positive affect on dogs’ ability to perform well on a memory-related task.
Dog's Life: Lifestyle
Similarities and differences in brain response
If you’ve read the headlines recently saying that science has proven that we love our dogs just like we love our kids, then you have only gotten part of the story. Yes, we love our dogs and consider them our children, and yes, a new research paper gives details about the similarities in the way our brains view these important individuals. However, there are nuances to the way our brains react to the world around us, and as is usually the case with scientific studies, it’s not that simple.
A study called “Patterns of Brain Activation when Mothers View Their Own Child and Dog: An fMRI Study” found both similarities and differences in mothers’ responses to dogs and children. Researchers evaluated brain function patterns in women when they saw pictures of their children and their dogs, as well as pictures of unfamiliar children and dogs. The study focused on areas of the brain that are involved in social bonding.
Mothers had similar activation patterns in some parts of the brain when they viewed photos of their children and photos of their dogs. These patterns differed from their responses to pictures of unfamiliar children and unfamiliar dogs. One region that responds similarly to these two types of images is relevant in rewards, emotion and affiliation. Another region of the brain involved in affiliation and reward was activated by images of mothers’ own children but not by images of their own dogs. An area of the brain that is critical to the processing of facial features was activated far more by images of mothers’ dogs than by images of their children.
According to the authors, “These results demonstrate that the mother-child and mother-dog bond share aspects of emotional experience and patterns of brain function, but there are also brain-behavior differences that may reflect the distinct evolutionary underpinning of these relationships.”
If you are a parent to both humans and dogs, do you feel both similarities and differences in those relationships?
Good Dog: Studies & Research
Author of Animal Madness: How Anxious Dogs Help Us Understand Ourselves
In an engrossing new book, Animal Madness: How Anxious Dogs, Compulsive Parrots, and Elephants in Recovery Help Us Understand Ourselves, science historian Laurel Braitman investigates the symptoms, causes and recoveries associated with behavioral disturbances in a wide variety of social animals. Starting with her own dog, Oliver, who suffered from debilitating separation anxiety, she discovered that mental illness in animals looks a lot like it does in people. In a recent conversation on a sunny afternoon in Berkeley, she shared some of her insights with us.
Claudia Kawczynska: In the book, you talk about the use of psychopharmaceuticals, pointing out that not only is one in five Americans on them, but also, increasing numbers of dogs are being given them as well. But there seems to be a divide in the veterinary field on their use. After looking into this subject, how do you feel about it?
Laurel Braitman: Sometimes our dogs need them, or the drugs are used as a band-aid to correct for stressors in a dog’s life that could be changed. Sometimes the drugs don’t work. They don’t always work for people either actually, but that doesn’t mean we shouldn’t try them in the right situation. E’Lise Christensen, a veterinary behaviorist, said that if the dogs she sees were humans, most of them would be committed to in-patient facilities. That is why she thinks drugs are useful in really extreme situations—to keep dogs from hurting themselves while giving behavior therapy time to work.
It’s really hard to generalize, though; so much depends on the individual dog. A certain dosage of, let’s say, Xanax, may make some dogs so blissed out that they don’t want a treat or whatever is being offered as an incentive. Other dogs might do really well on the same dosage. And different dogs will react differently to different drugs.
A lot of the behaviorists I spoke with are seeing dogs on dosages that would have calmed most canines, but are in the behaviorists’ waiting rooms because the drug didn’t work for them. There are also cases where a drug causes other issues—such as reducing inhibitions so that a previously-friendly dog becomes more aggressive.
CK: How similar are certain human and canine disorders?
LB: Panic disorders in humans are really similar to canine separation anxiety; when we’re flooded with panic, our first instinct is to escape. The same feeling drives the behaviors seen in many dogs anxious at being left alone; in my own dog’s case, he fled by jumping out of a window.
With humans, we assume that the roots of the disorder have to be dealt with in therapy over time—that we need to understand the triggers for someone’s panic. The approach for nonhumans should be the same.
Drugs are helpful when a dog is so upset, so distressed or suffering so much that the behavioral things that experts such as Ian Dunbar suggest just aren’t possible. Pharmaceuticals act like panic buttons; they can help the animal tap into the physical and emotional resources they need to be able to learn.
CK: It seems like there are at least two approaches to calming an anxious dog. Some veterinarians (such as the late Mel Richardson) believe that soothing an anxious dog isn’t the best approach—that petting only rewards the panicked behavior. But others, including Patricia McConnell, make a compelling case for the opposite approach. This is an important difference.
LB: McConnell is right! Dogs are complex thinkers and will not automatically equate you petting them with positive reinforcement. If they did, dog training would be a hell of a lot simpler! The example that Mel gave, and I included in the book, is different, however. A patient of his came in with a dog who acted scared in her living room, ever since a plate dropped off a wall during a fight the woman had with her boyfriend. The woman may have been rewarding her dog for hugging the sides of the room, not necessarily comforting him for something that was stressful. We do at times unwittingly positively reinforce our animals for behaviors we then find undesirable; but soothing your dog during thunderstorms or fireworks displays makes a lot of sense.
I always comforted Oliver during thunderstorms, I didn’t ignore him, and clearly if that worked he wouldn’t have had a thunderstorm phobia. I think we approach these problems with an almost patriarchal kind of “tough-it-up” attitude. It doesn’t work with children and it doesn’t work with dogs. It doesn’t account for the fluidity and complexity of the human or other animal mind. Dogs know we are reading their distress and they read ours. No other creature on the planet—including other people in my opinion—is better at reading our emotions than dogs. They’ve spent at least 15,000 years at it.
CK: Oliver was a purebred Bernese Mountain Dog. In your research, did you find that abnormal behaviors were more, or less, likely to be found in purebreds?
LB: I wish there were a good answer to that. Every behaviorist I spoke with, and many trainers, were familiar with breed-specific manifestations of mental illness. Tail-chasing, shadow-chasing, OCD. Oliver suffered from an extreme case of separation anxiety, but I didn’t find that was something frequently seen in Berners.
(By the way, I’m not saying that shelter dogs won’t have issues; they could have the same or different problems related to abandonment, phobias, or lack of socialization.) We should really have honest talks with breeders about the mental health of their dogs, but we rarely do. Every breeder will say that they breed “family” dogs. But I have to wonder if—once they’ve spent a fortune on breeding pairs, and the pups are potentially quite valuable—they will really take one out of the mix if he or she develops mental problems.
CK: It was interesting to read that Nicole Cottam, who was at Tufts Animal Behavior Clinic, thought that jealousy was the leading cause of canine aggression.
LB: Jealousy is an issue for many more creatures than dogs. It came up a lot in regards to other social animals too, like elephants and the other great apes. Why would we, or our dogs, be the only ones to experience it? Our pack, our families, our troops are everything and it can be threatening if we perceive, rightly or wrongly, that we may lose someone’s attention.
In the context of elephants, it’s a matter of public safety. Almost everyone I talked to in Thailand believed that most elephant-on-elephant and elephant-on-human violence comes from jealousy. If a young man who works with elephants visits a girlfriend, they say, he has to shower many times before he interacts with his elephant again and, sometimes even that’s not enough. He’ll need to bring a truckload of pineapples or bananas to win back the trust of his elephant.
Elephants can also be extremely dangerous if one of their elephant friends becomes closer to another elephant and ignores them. Or if a person is feeding elephants and doesn’t feed them at exactly the same time—that can be dangerous as well.
Dogs, of course, can be aggressive and protective around food. But perhaps it may also be that the dog is jealous—that he or she feels another dog is getting more of your attention because the other dog is being fed first.
CK: How can we know that dogs experience jealousy?
LB: Jealousy is actually the darker side of a positive emotion. That is, if we build our lives around those near to us and have close relationships with them, and then suddenly those relationships are taken away, we are going to feel bad. Everything in us wants to connect—we are social beings. Most of us are also our dogs’ primary “other” animal.
Clearly, that is what happened in my dog’s case. He went from being the center of his first family’s world to its fringes because there was a new baby in the house. [Ed. note: Oliver’s previous owners moved him to the garage, among other things, when he started to act out.] I have nothing but empathy for the family. They didn’t mean to hurt him; they just didn’t know what else to do.
CK: How do we know that dogs have these complex emotional experiences?
LB: There are many things we can’t test for specifically (even if we’re doing things like putting dogs inside MRI machines), but since we have been living with dogs for thousands of years, we owe them the benefit of the doubt. Actually, talking to friends at the dog park can teach us a lot. That’s how Darwin did it; he collected stories, then amalgamated the stories into a theory. His stories about his dogs are wonderful and clearly anecdotal—really the equivalent of talking to dog park people.
CK: Modern life can be difficult for dogs; most have far too little to do, and few opportunities to express their true “doggishness” or funktionslust (a great German word you use—taking pleasure in what one does best). For many dogs, that would be running, sniffing, chasing and so forth. How can we give our dogs more of what they need?
LB: Most dog owners have the best of intentions, but realistically, can’t pack up their urban lives and move to the country, or get a second dog to provide their dog with a companion.
But going to a dog park and spending most of our time engaged with our phones—emailing, tweeting, posting to Facebook—and then going home and sitting in front of the TV (even if our dog’s sitting with us) isn’t good for either of us. Most of the things that will make our dog feel better are things that will help us feel better, too. Neither humans nor dogs are prepared for many aspects of contemporary life. We spend too much time indoors, seated, by ourselves. . How all of this has affected our canine companions, we still don’t know, but it can’t help but contribute to some of the issues we are seeing in dogs.
CK: Our own dogs are almost always with us; they come to the office, they get long hikes in the local parks and so forth. But when we take them up to the country, they seem to come alive; they’re different beings. It is amazing to see how they behave when they have free access to the outside. They rarely nap during the day, they’re always alert—they just seem more fulfilled.
LB: It’s the stimulation, and we all need that. Dogs who are not as motivated or curious about their environment may need less stimulation, but they still need some.
CK: Behaviorally, there are similarities in canine and human cognitive decline, you point out that in dogs, as in us, it can perhaps be offset by mental stimulation and a diet rich in antioxidants. (As a devoted crossword puzzler and blueberry lover, I was heartened to read this.) Any more thoughts on this?
LB: Avoiding the problems of an aging brain, or at least slowing the process, is really at the forefront of human medicine now, and we ought to be looking into that for other creatures. Adding a miniscule amount of blueberries to dog treats isn’t going to do it, however—that’s crazy. But if we need another reason to stimulate our dog’s minds, this is it.
Puzzles we can solve together are fun. I played hide-and-seek games with my dog—that was a great brainteaser. Talk about memory! He would always look first in the last place I hid. Clearly, he thought, She was behind the fridge the last time so she’s probably there this time, too.
CK: We do this with our three all the time, and what I find interesting is that they never seem to use their noses to find us.
LB: I wonder if they may be “playing fair” with us, giving us a fighting chance. They might realize we’re so bad at this game, and know that if they use all their abilities, they would win all the time. End of game! No fun!
CK: People don’t seem to like complicated solutions, especially when it comes to dog training and behavior. We want to know the answer now. How do we accommodate that?
LB: I think it’s human nature to want answers, especially when we have an animal who is upset. It feels like life and death, and sometimes, it is; the stakes with this stuff are high. If a dog’s emotional problems manifest in aggression or make life too difficult and we can’t fix them, the dog can wind up at a shelter. People’s sense of urgency though can lead them to absolutes that don’t help them or their dogs.
I am hoping that this book helps people understand why helping dogs can be a little complicated and a lot rewarding. A dog’s social and emotional world isn’t as fixed as most people think it is, and on the positive side, a dog’s resiliency can work in our favor. Even though many dogs have every reason to not believe in the goodness of humans, they often do anyway, giving us chance after chance to help them. That is a magical, heartening thing.
For more insights, see the book review for Animal Madness.
Good Dog: Behavior & Training
New evidence from archaeological sites
Archaeological sites with hundreds of dead mammoths posed a puzzle to scientists: How could humans kill so many of these massive animals with the weapons available at the time? The answer is that one of the “weapons” used was not made of stone like the other tools of the time, but was made of flesh and blood. It was the domestic dog.
According to new research by Pat Shipman at Penn State University, humans may have been cooperating with some of the earliest domesticated dogs, which improved their mammoth hunting success considerably. The dogs could have contributed in a number of ways. They may have helped people find prey more quickly and more often. It’s possible that they held prey by charging and growling until the humans moved in to make the kill. After the mammoths died, dogs’ role in the hunt may have continued in the form of guarding the meat from scavengers or helping to carry it home.
Shipman developed several testable hypotheses about these new ideas. Based on analyses of what types of bones were present at the site (both dogs and wolves) as well as the cause of death of the mammoths, the idea that dogs were important in mammoth hunts about 45,000 to 15,000 years ago was supported. It is interesting that it was only during this time period that such large groups of hunted mammoths have been found, as humans (and their ancestors and extinct close relatives) began hunting mammoths over a million years ago.
A further piece of evidence that dogs were involved in mammoth hunting is the finding of a dog skull with a large bone, likely from a mammoth, that had been put in its mouth not long after it died. (That skull is shown in the photograph.) The find suggests that there were special rituals to acknowledge the dog’s role in mammoth hunting.
Knowing that modern dogs can suffer catastrophic injuries when hunting bears and wolves, I wonder how often dogs were wounded or killed in mammoth hunts.
Good Dog: Behavior & Training
Dogs and humans follow similar path
If you think that your dog has changed in his tendency to pay attention to you over time, you are probably right. A new study is the first to describe the developmental changes in dogs’ attention over their entire life.
In the study “Lifespan development of attentiveness in domestic dogs: drawing parallels with humans”, scientists studied 145 Border Collies from the ages of 6 months to almost 14 years old. Dogs were placed in 7 groups, reflecting these developmental periods: late puppyhood, adolescence, early adulthood, middle age, late adulthood, senior, and geriatric.
The researchers concluded that dogs (at least of this breed) show predictable changes in attentiveness, which they define as the ability to choose to process some environmental stimuli over others, as they age. Their major findings were:
Have you noticed changes in your dog’s attention habits over time?
Good Dog: Behavior & Training
Their brains reveal a positive response
You may not feel happy when you smell your husband’s underarm when he has not showered or used deodorant for 24 hours, but your dog probably does. So concluded scientists who conducted an fMRI study to investigate the response of dogs’ brains to both familiar and unfamiliar canine and human odors. Since the canine sense of smell is so well-developed, studies that investigate it are especially useful for learning more about dogs, including their behavior and emotions.
The 12 dogs in the study “Scent of the familiar: an fMRI study of canine brain responses to familiar and unfamiliar human and dog odors” (in press in the journal Behavioural Processes) have been trained to remain still during the entire procedure. Because the dogs don’t move during the process because of training rather than being medicated or restrained to achieve stillness, the way various areas of the brain respond to various stimuli can be studied. All of the dogs are family pets and were raised by people from puppyhood on.
In this experiment, researchers focused on the caudate, which is an area of the brain that is associated with positive feelings and rewards. The level of activity in this part of the brain in response to various odors informs us about the emotional reaction of dogs to various stimuli. The odors used were the dog’s own odor, a familiar dog, an unfamiliar dog, a familiar person and an unfamiliar person. The familiar person was never the guardian handling the dog at the experiment because the scent of that person was present throughout the experiment.
The scientists found that dogs had the strongest, most positive reactions to the smell of a familiar person. Because most of the handlers with the dog during the experiment were female guardians, the familiar person was usually the male guardian or their child, although it was sometimes a close friend. The familiar dog was also a member of the household. The scents from dogs came from the perineal-genital area.
The dogs responded to all of the scents, but activation of the caudate portion of the brain in response to the familiar human scent showed that dogs distinguished it from all the other scents and that they had a particularly positive association with that smell. Dogs had a more positive response to familiar humans than to either unfamiliar humans or to members of their own species, whether familiar or unfamiliar.
Interestingly, the four dogs in this study who are service dogs had the strongest responses to human scents, which may be due to genetics, their intense exposure to humans during training or even simply a fluke related to small sample size. It is possible that dogs whose caudate is highly responsive to human scent may be best suited for service work. Because not all dogs selected to be service dogs end up successfully completing the time-consuming and expensive training, choosing those dogs who are most likely to succeed could save time and money as well as lessen the extensive waiting times for people in need of such dogs.
Good Dog: Behavior & Training
The similarities are considerable
If you’ve always thought that you and your dogs understand one another’s emotions, you increasingly have scientific evidence supporting your views. The use of MRIs allowed researchers to demonstrate that the brains of both dogs and people have a similar response to human voices, crying and laughter, among many other sounds. Researchers conclude that the brains of both dogs and people have similar reactions to the emotional cues in many sounds.
Eleven dogs and 22 people were subjected to the same MRI scans during which they had to remain still for up to 8 minutes while exposed to various sounds. (A lot of training went in to teaching dogs to remain motionless during the scans.) The study is called “Voice-Sensitive Regions in the Dog and Human Brain Are Revealed by Comparative fMRI” (only the abstract is available online) and it was published last week in the journal Current Biology. It is the first study to use this technique to compare the brain of humans to a non-primate animal species.
Over 200 different sounds were played to each participant in the study over a number of sessions. There were sounds such as whistles and car noises as well as dog vocalizations and human sounds. The responses to human sounds in both people and dogs occurred in similar regions of the brain. This study is the first time such a similarity to humans has been shown in an animal species that is NOT a primate. Both the people and the dogs also reacted in similar regions of the brain to emotional canine vocalizations such as whimpering and intense barking.
Along with the similarities, there were also differences in responses between the two species. Humans were better at distinguishing between the sounds of the environment and vocalizations than dogs were. Additionally, both species responded more strongly to vocalizations of their own species.
It is impossible to say from this study whether these vocal regions of the brain evolved in a more ancient lineage than was previously thought or whether the dogs have evolved this similarity during the period of domestication as a mechanism to allow better communication and understanding between dogs and people.
Future studies that investigate brains of additional species may be able to determine the reason for the similarity between dogs and people. These scientists next plan to study the response of dog brains to human language, which was not a part of this study.
Good Dog: Behavior & Training
Dog flexibility strikes again
If you’re not amazed by the diversity of dog body type and the huge number of habitats in which they can live, then you’re in the minority. Scientists, dog lovers and scientists who are dog lovers consider the domestic dog a species of considerable interest for the great number of forms that have evolved over a relatively short time. Some of the variation is obvious because it involves shape, size and color, while some of the behavioral tendencies are subtle. Even less obvious are the physiological difference between different types of dogs, including the recent discovery of adaptations to high altitude by the Tibetan Mastiff.
This breed of dog is most closely related to the Chinese native dogs, but in recent history, has been selected to live high in the mountains of Tibet at elevations of nearly 15,000 feet. The biggest challenge to life at such heights is the low level of oxygen. Even individuals who are quite fit can become out of breath just from walking at a casual pace under the low oxygen (hypoxic) conditions at high altitude. So, how do Tibetan Mastiffs thrive in Tibet? They do it in much the same way that wild animals and humans do—with genetic changes that affect hemoglobin concentration, the formation of extra blood vessels and the use and production of energy.
In a new study called “Population variation revealed high altitude adaptation of Tibetan Mastiffs”, scientists found that this breed of dogs has at least a dozen areas in their genome that represent adaptations to the high life. One of the genes that helps them survive in their high-altitude/low oxygen environment is similar to a gene present in the Tibetan people, who are also adapted to the high life. The rest of them are different than those of the people as well as differing from animals such as the yak and the Tibetan antelope that are also adapted to this environment.
Though much selection on our companion dogs has changed their behavior and appearance, there are also examples of changes that are far harder to observe such as the Tibetan Mastiff ‘s adaptations to high altitude.
Dog's Life: Lifestyle
Infantile features have power
Those big puppy dog eyes may be powerful in addition to just being cute. According to a recent study, they may actually affect human choice about which dogs to adopt. The researchers who conducted the study “Paedomorphic Facial Expressions Give Dogs a Selective Advantage” found that dogs whose facial expressions made them look more puppyish were adopted more quickly from shelters than dogs who did not show such facial expressions. (Paedomorphism is the retention of infantile or juvenile traits into adulthood.)
One of the most prominent paedomorphic features is large eyes relative to the size of the face. This trait can be enhanced by raising the eyebrows which makes the overall height and size of the eyes seem bigger. It was this action of eyebrow raising that was studied in the experiment.
A total of 27 dogs were a part of the study. To minimize variation in facial features, all of the dogs were of similar types: Staffordshire Bull Terriers, Mastiffs and mixed bull breeds. Dogs were filmed for 2 minutes and researchers recorded the number of eyebrow raises and tail wags that each dog performed as well as noting how much time the dog spent at the front of the kennel. Frequency of eyebrow raises was associated with shorter times until adoption. Specifically, dogs who raised their eyebrows 5 times during filming were adopted in an average of 50 days, those that performed 10 eyebrow raises were adopted in an average of 35 days, and dogs who did it 15 times had an average waiting time until adoption of only 28 days.
Interestingly, they found that amount of tail wagging and time at the front of the kennel were not strongly associated with time until being adopted even though such traits are typically considered favorable behavioral signs of friendliness. It would be interesting to know if the eyebrow raising behavior correlates with temperament and suitability as a pet or if it is a behavior that serves more strictly to encourage caregiving behavior in humans.
These results may shed light on the domestication of dogs. It has been proposed that the juvenile traits of dogs arose as a byproduct of selection against aggression. This line of reasoning claims that people chose to associate with the least aggressive canines, and that the evolution of puppyish features and behavior developed as an accidental consequence of those choices. Experiments support the idea that selecting against aggression does lead to the evolution of juvenile traits. However, this latest study suggests that the puppylike features themselves may have influenced which canines became closely associated with humans and that such features may have evolved earlier in the process of domestication than previously thought.
Do your buddy’s puppy dog eyes exert a powerful influence over you?
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