Dog Behavior Blog

When You Are Generous, Your Dog Is Watching You

Some people have generous natures, and some people are miserly. The generous ones are happy to share what they have with others, while the miserly folks resent having to share anything with anybody.

So if given the choice, which type of person would a dog likely approach first?

If you guessed the generous one, you guessed right.

But how do dogs know this? A recent study in the journal Animal Behaviour reported on experiments where dogs were given the opportunity to interact with generous vs. non-generous people, and the study examined the cues that the dogs used to make a decision about whom to interact with (Marshall-Pescini et al. 2011. Social eavesdropping in the domestic dog. Animal Behaviour (2011), doi:10.1016/j.anbehav.2011.02.029).

The study used 100 dogs of mixed breeds and ages. In the experimental setup, a dog and the dog’s person were allowed to go into a small room, and the dog was given the opportunity to explore the room. Then the dog and person sat down along one side of the room while two people unfamiliar to the dog entered the room. Each of these two people had a bowl of cereal and a bowl of sausages, and each came up to the seated dog and allowed the dog to smell both bowls. Then the two people sat down facing each other, and started to eat small quantities of cereal.

A third person entered the room, came up to each of the two people facing one another, and begged for food. One of the two people, the generous one, let the person have a morsel of cereal, saying “Have it.” and placed a bit of food in the beggar’s mouth.  The other person, the non-generous one, told the person “No” and made a gesture as if pushing the beggar away. The beggar moved from one person to the next six times, each time either getting a morsel of food from the generous person or being told “No” by the non-generous one.

Following these interactions, the beggar left and the dog was allowed to roam around the room for 20 seconds, during which time the experimenters monitored who the dog interacted with the most: the generous person, the non-generous one, or neither.

The end result was that most dogs spent more of their time either looking at or interacting with the generous person while mostly ignoring the non-generous one.

The experimenters tweaked these experiments to see if just voice alone (without the gestures) was enough, or if just the gestures (without the voice) made a difference, or even if the dogs would respond if people made the gestures and said the words but no beggar was present.

The dogs did best when voice was combined with gestures, although they also did well with just the voice alone. They did not seem to recognize what was happening when just the gestures were used (putting food in the beggar’s mouth vs pushing beggar away), perhaps because these gestures were relatively similar.

When no beggar was present, the dogs did not distinguish between the generous and non-generous person, indicating that they were watching what happened to the beggar rather than just tuning in to the voice and the gestures.

Those of us who have trained dogs know that we can get a dog’s attention by sharing food with the dog. But this study puts a novel twist on food sharing: Dogs can assess who shares food with other people, and look to that person as a likely candidate for sharing food with the dog.

So the next time you have people over for a dinner party, be sure to be generous in handing out food.

You need to impress your dog with your generosity.

--Con Slobodchikoff

 

When You’re Smiling, Your Dog Smiles With You

My Standard Poodle Raja likes to sleep in during the morning. Hours after everyone in the house has gotten up, Raja is still asleep under his blanket, dead to the world. Eventually he gets up and walks around the house looking for people to say “Good Morning!” When I see him coming down the hall, I smile at him, reach out and give him a morning massage while his tail wags furiously. If I pay attention, I see that he is smiling too.

I have always assumed that he is smiling because he loves the petting and the massage. It makes me feel good to pet him, lowering my blood pressure, which already is rising with the stress of the coming day.

But could he be responding to my smile? If I were asked this question a few months ago, I would have answered, Of course not!

Now, however, there is an article in the journal Animal Cognition by four researchers in Japan who say that dogs can indeed recognize the smiles of their owners (Nagasawa et al. 2011. Dogs can discriminate human smiling faces from blank expressions. Animal Cognition online 26 February 2011).

In their experiments, the researchers trained five dogs to respond to photographs of human faces. During the training phase, the dogs were shown two photographs: the smiling face of a university student, and the back of that student’s head. They were rewarded for choosing the photograph of the smiling face.

Then  the experimenters showed each dog a photograph of their owner’s smiling face vs. their owner’s face with a neutral expression, repeating this ten times with each dog. The dogs chose the photograph of the smiling owner’s face between 80-90 percent of the time, significantly above chance levels (chance would be choosing the smiling face and the neutral face 50 percent of the time each).

The experimenters then went one step further and showed the dogs photographs of the smiling face and neutral face of unfamiliar people of the same gender as the dogs’ owners. Again the dogs chose the smiling faces between 70-90 percent of the time.

The last experiment turned out to be something of a puzzler. The experimenters showed the dogs both smiling and neutral photographs of faces of the opposite gender as the dogs’ owners. Now the dogs fell to chance levels, suggesting that they couldn’t tell the difference between the smiling face or the neutral face of someone with whom they weren’t familiar. This last response suggests that it isn’t just simple conditioning where the dogs have learned to respond to a smile, regardless of the face.

We can ask why. Maybe dogs have to learn that the smile on their owner’s face is associated with positive things, such as a food reward, a walk, or strokes. Or maybe dogs just feel good around their owners and not as good around other people. Maybe they feel particularly good when the owner’s emotion, expressed as a smile, washes over them. Clearly we still have a lot to learn about this.

But I know one thing. I feel good when I see Raja coming down the hallway, and I am pretty sure that Raja feels good when he sees me smiling.

--Con Slobodchikoff

Dogs Assess Reputations

We all know someone who has a bad reputation. Backstabber. Malicious gossip. Liar. Cheater. Gets unpredictably angry. And we try to keep that reputation in mind when we deal with the person. If you are like me, you might give the person the benefit of the doubt, but then when it happens to you, you back off and are no longer willing to trust the person. As the saying goes, once bitten, twice shy.

But can dogs assess who has a bad reputation? On the surface, the answer seems to be easy – Of course not. Dogs are supposed to be friendly toward everyone, and are supposed to lack the thinking skills that would allow them to form a judgment about reputations.

Not so fast, however, with the easy answers.

A new study appearing in the journal Animal Cognition shows that dogs can make some pretty good judgments about people’s reputations (Kundey et al. 2011. Reputation-like inference in domestic dogs (Canis familiaris). Animal Cognition 14: 291-302).

The experimenters used a very clever trick. While a dog was watching, they had two people kneeling side-by-side in front of another person who was kneeling facing the other two. The two kneeling people each gave the  person facing them a treat by placing the treat in front of the person. But one of the two givers consistently took the treat back, while the other giver allowed the person in front of them to take the treat. Then each of the givers offered the dog a treat by placing the treat in front of them, just like they did when they were offering the treat to the person. The dog was allowed to choose whose treat to take.

All ten dogs in this experiment chose to take the treat from the giver who didn’t take back the treat.

To control for unintentional cues, the experimenters tried a variety of modifications of this experimental design, each with about ten new dogs. In one modification, the givers were kneeling facing away from the recipient person, and had to reach backward to offer the treat. In another modification, the givers were not people, but large cardboard boxes with people inside reaching out to put down the treats. In a third modification, the recipient was a cardboard box.

In each case, at least nine of the ten dogs chose to take the treat from the giver who didn’t initially take the treat back.

The experimenters concluded that the dogs formed a concept of the reputation of each of the givers: one giver was reliable in offering the treat, while the other one was unreliable.

Let’s extend these results to our dogs. How many times have you yelled at your dog, hit your dog, yanked your dog by the collar or leash, or otherwise acted in an unpleasant manner toward your dog (my hope is that your answer is “zero”)? For those who do that, these experiments imply that dogs are forming a concept of the reputation of their people.

Just as we don’t do well in an environment of working with a boss who has a reputation for being unpleasant, maybe dogs don’t do well living with people who have a reputation of being unpredictable.

And maybe dogs act out when they get a concept that the person that they are living with has a bad reputation.

The moral of the story is, be nice to your dogs.

--Con Slobodchikoff

Chaser, The Dog Who Knows 1000 Words

How many words of dog language do you know?

Oh, that’s right, dogs aren’t supposed to have a language with words. They merely have a communication system, where their barks, whines, growls, raised heads and wagging tails are simple expressions of emotion, but nothing to do with words. What a relief!

But what if it isn’t true? What if dogs have a language of their own, with gestures, growls, and barks that are the equivalent of words and sentences? What then?

Scientists who have been interested in knowing whether animals have language have often tried a back-door approach. If you can teach an animal a human language (or something artificial made up by people) then it might imply that the animal has the cognitive capacity to have a language of its own. No guarantee, of course, but at least it shows the possibility.

To this end, we have had studies of teaching sign language to chimps (such as Washoe), teaching keyboard symbols to bonobos (such as Kanzi), teaching English words to parrots (such as Alex), and teaching artificial gestural and sound languages to dolphins (such as Akeakamai and Phoenix).

And what do you know, they all can understand, and some can or could communicate back to the experimenters, much to the chagrin of the naysayers who insist that language is exclusively the property of people.

As far as dogs go, a group of scientists reported in 2004 that the Border Collie Rico could understand 200 words, and if given a task of retrieving an object  whose name Rico did not know from among a group of objects whose names he did know, he could make the intellectual leap and assume that the unknown name that was given stood for the one object whose name he did not know.

Now comes an article in the scientific literature about a Border Collie called Chaser, who knows more than 1000 words (Pilley, J.W. and A. K. Reid, 2011. Border collie comprehends object names as verbal referents. Behavioural Processes, doi:10.1016/j.beproc.2010.11.007).

Over a three-year period, Chaser learned the names of more than 1000 objects (specifically, 1022 objects), which were all proper nouns relating to stuffed toys, Frisbee-like objects, or balls. Like Rico, she could retrieve an object whose name she did not know, when she was asked to find that object from among a series of objects whose names she knew. She could also understand broad categories, such as “toy”, “ball”, and “Frisbee” and could correctly select the right kind of object when told to fetch, for example, a “ball” from a selection of objects that included a number of other things.

Even more impressive, for those of us whose dogs chew our slippers, is that Chaser learned to distinguish between “toy” and “non-toy” when the objects were very similar. Toys were things she was allowed to play with. Non-toys were similar objects that she could see but was not allowed to touch, such as cloth animals, balls, dolls, or shoes that were visible to her. So she generalized the categories “toy” and “non-toy” by function: “toys” were things she was allowed to play with, and “non-toys” were things she was  forbidden to touch.

It looks like Chaser could understand a lot of what was said to her. The experimenters did not specifically test for her understanding of sentences, but when they told her: “Fetch the ball,” that pretty-much implies that she could understand sentences at some level.

So much for the argument that dogs only understand your tone of voice.

And by the way, how many words of dog language do you know?

--Con Slobodchikoff

Size Of Tail Messes Up Dog Language

We all know that dog tails communicate information to other dogs and to people: happiness, friendliness, playfulness, fear, aggression, and status.

But what happens when the tail is artificially shortened (docked)? Are other dogs affected by this tail shortening? In the United States at least, more than one third of all dog breeds have traditionally had their tails docked. What does this is do to dog body language?

This is been a difficult question to answer scientifically because experiments have been so hard to perform. If you're using live dogs with short and long tails to study this question, you have a lot of factors other than tail length that could confuse the issue. You have all kinds of body scents, ear positions, general body posture, and behavioral interactions that can modify the response of other dogs to short or long tails.

A recent behavioral tool has been to use robots to study the behavior of other animals. With a robot you can test for specific things, such as a short tail versus a long tail on a dog, and everything else stays constant: the robot is still the same size, stays in the same position, doesn't have any confusing smells, and doesn't engage in any behaviors that could modify the response of an approaching animal.

Using a robot, a study has recently looked at the effect of short and long tails on the approach behavior of other dogs (Leaver, S.D.A. and T.E. Reimchen. 2008. Behavioural responses of Canis familiaris to different tail lengths of a remotely-controlled life-sized dog replica. Behaviour 145:377-390).

The experimenters did this study in a place where there are a lot of off-leash dogs in Victoria, British Columbia, Canada. They used a robot about the size of a Labrador retriever, and attached to the robot either a short tail (9 cm or 3.5 in) or a long tail (30 cm or 12 in). Using a servo mechanism, they could make the tail either wag or stand still. They videotaped the approaches of 492 off-leash dogs and assessed the conditions under which the dogs either freely approached the robot or hesitated in their approach.

They divided the approaching dogs into two categories: smaller dogs (those whose shoulder was below the shoulder of the robot) and larger dogs (those whose shoulder was above the shoulder of the robot).

They found that the dogs differed in their approach to a short tail versus a long tail.

Both larger and smaller dogs tended to approach the robot without hesitation when the robot had a long, wagging tail, and tended to hesitate more when the long tail was motionless. We might expect this because a wagging tail generally signals friendliness while a motionless tail can signal potential aggression.

On the other hand, both larger and smaller dogs seemed to have a difficult time determining whether the short tail was wagging or still. Both the larger and smaller dogs tended to approach either the wagging short tail or the still short tail at about the same rate, a rate that was below the rate of approach for a long wagging tail and above the rate of approach for a motionless long tail.

It was as if the dogs couldn't see the difference between a wagging short tail or a motionless one and had to make a guess as to whether to approach or not.

So it seems that tail docking does introduce some confusion into dog language, making it more difficult for dogs to determine whether a dog with a short tail is friendly or potentially aggressive.

Fortunately for dogs, the practice of tail docking seems to be decreasing in frequency, allowing more dogs with normal-sized tails to be able to accurately communicate their intentions to other dogs.

--Con Slobodchikoff

 

What Do Dog Growls Mean?

Your dog growls at you when you try to take away his food dish. Then he growls at you when you are playing tug with him. Can you tell the difference in the growls? Or does one growl sound like another to you?

It turns out, dogs can tell the difference between these two types of growls.

A study using 41 dogs of various breeds tested whether dogs can tell the difference between growling when another dog approaches food, growling when an unfamiliar stranger approaches, and growling while playing tug (Farago et al. 2010. This bone is mine: affective and referential aspects of dog growls. Animal Behaviour 79: 917-924 doi:10.1016/j.anbehav.2010.01.005).

The experimenters recorded dog growls in all three contexts. Then they played back the different growls to a dog approaching a bone. Here’s how it was done: a dog was allowed to approach an untended bone, and when the dog’s nose was close to the bone, the experimenters played back either a food guarding growl, or a threatening stranger growl, or a tug growl.

The results were striking. When the food guarding growl was played, 11 of 12 dogs withdrew from the bone. Compare this with the other growls: 2 of 12 dogs withdrew from the bone when they heard the threatening stranger growl, and 4 of 12 dogs withdrew when they heard the play tug growl.

Clearly, the dogs understood the meaning of the growls.

All three types of growls had different acoustic properties in terms of pitch and places where the most sound energy was concentrated (called “formants” in human language).

Interestingly enough, the food guarding growls and the threatening stranger growls were lower in pitch than the play tug growl. This is a common theme in aggressive vocalizations of many mammals: lower pitch (within the pitch range of the vocalizations that the animal makes) often means aggression.

Increasingly, scientists are finding that more and more animals have a language. To be fair to my scientific colleagues, most of them prefer to use the term “referential communication” rather than “language”. But I prefer to quote Shakespeare: “What’s in a name?  That which we call a rose by any other name would smell as sweet.” And it’s sweet  to know that scientific experiments are starting to show that dogs can smell the roses.

--Con Slobodchikoff

Ethology Nobel Laureate Konrad Lorenz

As this year’s Nobel Prizes were announced, I faced my annual wish for anyone interested in dog training and behavior to know that three scientists in the field of Ethology have been awarded this prize. In 1973, Niko Tinbergen (The Netherlands), Karl von Frisch (Austria), and Konrad Lorenz (Austria) were awarded the Nobel Prize in Physiology or Medicine “for their discoveries concerning organization and elicitation of individual and social behaviour patterns.” They are regarded as being among the founders of the field of Ethology, which is the study of animals in their natural habitat.

While they are best known for their work with birds, insects, and fish, all of them studied a variety of species. Konrad Lorenz was quite interested in dogs, and wrote a wonderful book called Man Meets Dog. One of the great contributions of this book to the study of animals concerns Lorenz’ interdisciplinary approach to understanding dogs. As Donald McCaig states in the introduction to a recent edition, “He made it respectable to bring the practical observations of animals trainers and handlers into the academy. It was a great first step, and although the gulf between academic study and practical applications remains with us today, Lorenz did much to merge what is known from different areas into a cohesive body of knowledge in order to further our understanding of animals.

(photo: Konrad Lorenz, Eurobas, wikipedia.org)

Some of my favorite aspects of this book are personal stories. For example, Lorenz describes the close relationship between his future brother-in-law, Peter, and a Newfoundland named Lord who joined the family when the dog was 1½ years old. Peter was the smallest of four brothers, and the youngest in a gang of boys who participated in their fair share of mischief. The dog protected him to such a degree that even his schoolmaster dared not raise his voice to Peter, lest he growl and leap up with his massive size on the shoulders. Naturally, this dog kept the other boys from teasing or bullying him as well.

Lorenz discusses his great sadness at losing dogs to old age. When he was 17, his dog Bully died of a stroke and he describes his sadness that the dog had left no offspring. For a long time after Bully’s death, Lorenz says he heard the pattering of Bully’s peculiar gait following after him as he had done for so many years in life. He writes, “If I listened consciously, the trotting and snuffling ceased at once, but as soon as my thoughts began to wander again I seemed to hear them once more.” Only when his new puppy Tito began to run behind him and follow him everywhere did the “ghost” of Bully cease to follow him in his mind.

Years later when Tito died, Lorenz felt a great guilt knowing that another dog would take the place of Tito just as Tito had replaced Bully in his heart. He says he felt ashamed of his own unfaithfulness and decided that for the rest of his life, only descendents of Tito would be his companions.

--Karen London

 

Toys That Dogs Like

My Standard Poodle Raja loves to play "ball." In his case, "ball" is anything that he can chase, catch, and bring back to the person throwing the "ball." Although he will do this with round balls that he can fit into his mouth, he really prefers plush toys that look like chipmunks or rabbits, that are small enough for him to fit into his mouth, and that squeak when he chews on them.

The downside of his playing "ball" is that he needs to convince some willing person to play this game with him.

What about dogs who don't have a person around? What sort of toys do they like to play with?

When I tried to find some scientific articles that have looked at this, I found that few had studied this problem.

However, a recent article in the scientific literature investigated what sorts of toys dogs in kennels like to play with (Pullen, A J et al. 2010. Preferences for toy types and presentations in kennel housed dogs. Applied Animal Behaviour Science 125: 151-156).

The experimenters studied the kinds of toys that dogs liked to play with in two different types of kennels:

· Re-homing kennels (the equivalent of Humane shelters), where dogs are brought in off the street for adoption.

· Long-term kennels where dogs spend most of their lives in a kennel.

The circumstances of kennel life were very different between the two types of kennels. In the re-homing kennels, the environment was very new to most dogs and the dogs showed signs of stress at being in unfamiliar surroundings. In the long-term kennels, the dogs were used to being in the kennels and received a lot of enrichment in the form of off-leash walks and interactions with people in an enclosed environment.

The experimenters gave both groups of dogs two types of toys to play with, and recorded the amount of play on video:

· One type was robust toys, which were difficult for the dog to destroy. These included a large indestructible ball, a rope tug knotted at both ends, a nylon and rubber flexible tug toy, and a rubber frame toy.

· The other type was less robust and easier for the dogs to damage. These included a vinyl bone with a squeaker, a soft fabric toy with two squeakers, a plush toy with a squeaker, and a tennis ball.

The robust toys were presented to the dogs as either hanging toys, suspended by a metal chain into the middle of the kennel, or as floor toys, placed onto the floor of the kennel.

The less-robust toys were only placed on the kennel floor.

Although there were some differences between the responses of the dogs in the re-homing kennels and the dogs in the long-term kennels, there was a common thread:

· The dogs generally did not like to play with toys that were hanging.

· The dogs preferred the soft squeaky toys to the hard indestructible ones.

While the indestructible toys are more attractive to people because dogs can't shred them, the indestructible toys are less attractive to dogs.

However, dogs can destroy the soft squeaky toys and possibly swallow pieces of the toy or the squeaker.

That means that if you give soft squeaky toys to your dogs, you have to watch them to make sure that they don't swallow anything.

I'm sure that Raja would agree with the results of this experiment. The only thing that they left out, in his opinion I am sure, are the people who can throw the soft squeaky toys for him to retrieve.

--Con Slobodchikoff

 

Why Dogs Eat Grass

These summer days, when I take my Standard Poodle Raja for a walk, he always wants to stop and eat grass. Not just any grass. The leaves have to be the right size and shape. Although there are other grasses nearby, he always heads for wheatgrass (Agropyron), with its broad green leaves.

I have read that dogs eat grass because they want to vomit or because they are having digestive troubles.

Raja hates to vomit. He will do anything to keep from vomiting, so that doesn't seem to be the answer, at least as far as he is concerned.

I feed him premium wet food, and he digests it very well, with well-formed stools (I get to sample these on walks, picking them up with my plastic bags). Digestive troubles do not seem to apply to Raja either.

So because the two explanations I have read do not seem to be relevant to Raja, I decided to dig a little bit into the scientific dog literature to see what I could find.

Surprisingly little has been written in scientific journals about why dogs eat grass.

One recent study approached grass eating in dogs with the hypothesis that grass alleviates digestive distress (McKenzie et al. 2010. Reduction in grass eating behaviours in the domestic dog, Canis familiaris, in response to mild gastrointestinal disturbance. Applied Animal Behaviour Science 123: 51-55).

In that study, the authors fed dogs a diet that produced loose, watery stools, to mimic a condition of a mild digestive upset. They also fed the dogs a standard diet that produced normal stools, and gave the dogs two types of grasses to eat during each experimental condition.

The results were that the dogs ate more grass when they were fed a standard diet than when they ate the diet that caused the digestive upset. So much for that hypothesis.

Then there's vomiting.

I found a study that looked at whether dogs vomit more when they eat grass (Sueda et al. 2008. Characterisation of plant eating in dogs. Applied Animal Behaviour Science 111: 120-132),

In that study, the authors surveyed 1571 dog owners on the internet and found that 79 percent of the dogs ate grass, and of these, only 9 percent were sick before they ate the grass, and 22 percent vomited after eating the grass.

These results show that the vomiting hypothesis doesn't seem to hold any water either.

So why do dogs eat grass?

Ask yourself that question the next time you eat a luscious salad.

My guess is......because it tastes good.

--Con Slobodchikoff

Puppies Get Socialized By Watching TV

My Standard Poodle Raja has no interest in watching TV. Dogs could be cavorting and barking across the screen, and he could care less. Even closeups of dog faces produce no results. If I try to call his attention to something that I think might interest him, he will sleepily open an eye out of politeness and then promptly go back to sleep on the couch in front of the tube.

I have always assumed that this is because dogs see TV screens differently from us. The typical screen flickers at 50-60 cycles per second (Hertz for the technically-minded), which is adequate for our eye to fuse it into a solid picture (again, for the technically-minded, the flicker-fusion-frequency). Dogs, on the other hand, fuse flickers into solid pictures at around 70-80 cycles per second, far above the flicker of the TV screen. Instead of a solid picture, they must see a whole bunch of flickers.

However, a recent study has found that puppies that are 3 to 5 weeks old can see a TV screen and respond to the objects that they are seeing on the TV (Pluijmakers et al. 2010. Exposure to video images between 3 to 5 weeks of age decreases neophobia in domestic dogs. Applied Animal Behaviour Science 126: 51-58). The study played back both sounds and sights of people, dogs, traffic, and objects such as vacuum cleaners, in an 8 minute video clip that was played to the puppies each day for 2 weeks from the time the puppies were 3 weeks old until they were 5 weeks old.

The study found that puppies who were exposed to different images and objects on the TV screen at that early age were much less fearful of strange situations by the time they were 8 weeks old. This is a critical time for puppies, when they are learning about the world around them, and what they learn during this time stays with them for the rest of their lives.

And fearfulness can affect a dog's lifespan. Another recent study found that fearful dogs had a significantly shorter lifespan than more confident dogs, probably as a result of constant stress (Dreschel, N. A. 2010. The effects of fear and anxiety on health and lifespan in pet dogs. Applied Animal Behaviour Science 125: 157-162).

So why is my Raja so uninterested in watching the TV, if 3 week-old puppies can see what is happening on the screen? The short answer is, I don't know. But a longer answer might be that he probably was never exposed to the TV as a puppy, and never got used to watching. He came to us as an adult rescue dog, and I have no idea what his early background was.

Chances are, by the time he saw a TV screen, it was already too late for him to make any sense out of it.

Sometimes, I think he has a point.

--Con Slobodchikoff