Play Signals as Punctuation (Thurs)

November 17, 2010 15 comments

We’ve all seen dogs playing with each other, but have you ever wondered whether or not you should intervene when the play seems to get too rough? Marc Bekoff investigated how play signals play a role in the social play of canids. Specifically he investigated how play signals initiate and maintain social play with an action performed by dogs called “the bow.” “The bow” consists of an animal crouching on its forelimbs while still standing on it’s hind legs and including other actions like wagging of the tail or at times even barking. It has been observed that other canids, besides dogs, use “the bow” in order to initiate play. It has also been observed that these canids use “the bow” in between play with no real determined sequence, meaning the action was used randomly. In addition to “the bow,” many canids use biting in play, but since biting can also be used for predation, it can often be misinterpreted. Therefore, Bekoff wanted to further investigate if the bows not performed randomly during play were actually used to indicate to the other canid that any action, like biting, should not be misinterpreted as harmful and instead be interpreted as playful.

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Categories: Uncategorized

Play Signals as Punctuation (Wed)

November 16, 2010 19 comments

How do dogs maintain their play, how do they reinforce their benign behavior, and when they have gone to far what do they do in order to reduce any hint of aggression they falsely gave off? Marc Bekoff questioned how dogs reinforce their play with signals, focusing on a particular move “the bow.” The bow is performed by the dog crouching its forelegs while keeping the hind legs normal, accompanied by wagging their tail or barking. From this posture the dog is still able to comfortable move into other positions, meaning that it doesn’t make the dog vulnerable to attack. Previous research has shown that dogs use this bow to initiate playing, and use it constantly throughout their play; but not at a normal intervals. This means that the bow is purposely executed and Bekoff’s hypothesis is that bows are used before and immediately after any actions that can be thought of as aggressive and interrupt ongoing social play. This study observes the actual structure of play sequences. Bekoff notes that although many actions in play are used aggressively in other contexts such as biting, the bow is not present in aggressive contexts, which may feature a rapid side-to-side shaking of the head. Bekoff thinks the bow is the key to play, as it is their sole communication to defuse a threatening action.

The video below has some great examples of the bow:

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Categories: Uncategorized

Testing the Social Dog Hypothesis (Thurs)

November 9, 2010 20 comments

Research has shown that dogs have superior social skills to other animals when it comes to contact. This finding is especially evident when it comes to communicative and cooperative tasks with humans, For instance, dogs are especially skilled at using human social cues such as human gaze and a pointed finger gesture to figure out where hidden food is. Furthermore, studies have shown that this seems to be an almost innate skill for dogs as puppies don’t need to have spent much time around humans before they pick up on these social cues. Studies have also led researchers to believe that these specialized social skills are likely a result of the domestication of dogs.

Reid PJ a scientist at the Animal Behavior Center in Urbana Illinois looked into this question of why dogs have these specialized social skills for his article, “Adapting to the human world: dogs’ responsiveness to our social cues”. He began his study with four possible reasons for why dogs have developed these skills; due to dogs increased opportunity over other animals to learn about human social cues, as a result of domestication, as a result of dogs co-evolution with humans, and due to the fact that sensitivity to human behaviors can be especially beneficial to the “social scavenger” nature of dogs. Similar to other researchers findings his studies pointed towards domestication as the primary cause for dogs advanced social skills.

Although it has been well proven that when it comes to communicative and cooperative social skills dogs excel. In the study in this article, researchers investigated to try and figure out whether these advanced skills are simply a narrow specialization or whether dogs have advanced social skills out of those. To study this, research compared to the behavior of dogs to chimps. In the article, the researchers investigated this by creating a non-social and social version in an experiment of reversal learning. In the social version of this test the subjects choose between two different humans one of whom has a reward. Once the subject recognizes which of the humans always has the reward the “association” is switched and the other human has the reward. Similarly, in the non-social version the subject must choose between two differently colored objects one of which has a reward, although, the social version includes humans, the humans did not engage in any social cues with the subjects. Multiple outcomes were possible form this experiment either both dogs and chimps could show no difference in results between the social and non-social version of the tests or either one could show an increased response to the social version of the test. If dogs, in fact, showed an increased response to the social version of the test it would provide evidence that dogs have advanced social skills beyond their cooperative and communicative skills.

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Categories: Uncategorized

Testing the Social Dog Hypothesis (Wed)

November 9, 2010 16 comments

Past research into Canine Cognition has revealed that domesticated dogs do not only posses greater social skills than undomesticated dogs, but that they possess social skills that exceed those of other animals. As some previous studies and some of the our own blog posts have shown, domesticated dogs have a unique ability to learn from humans and to use humans’ social cues to their advantage.

However it is unclear how specialized dog’s social skills are. Can dogs use their social skills beyond their interaction with humans? Research into this question has not led to conclusive results. One study has researchers concluding that dogs are better at applying human communication than chimpanzees do, but that chimpanzees are better than dogs at non-social learning. (Brauer et al., 2006). Victoria Wobber and Brian Hare, the authors of this paper were intrigued by the use of chimpanzees as a control in measuring the social and learning abilities of dogs and decided to use this comparison in their own study.

In their study, Wobber and Hare set out to see if dog’s ability to learn is not dependant on their ability to understand human social cues. In their paper, Wobber and Hare specifically state, “We aim to understand the extent of dog’s ability to reason about the social world, specifically by comparing chimpanzees and dogs in a social context that does not involve cooperative communication.” Wobber and Hare believe that experiments and observation will lead them to better understand whether dogs can learn from non-social cues or whether their great ability to learn is limited to their ability to understand humans. If the latter is in fact proven, Wobber and Hare believe that it is fair to conclude that dog’s great ability to understand humans is due to domestication.

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Categories: Uncategorized

A Simple Reason for a Big Difference (Thurs)

October 26, 2010 14 comments

Dogs are known to have beautiful eyes that come in many different colors, whether they are blue, green, gray, hazel, brown or even a mix of colors. Pass the aesthetics though, dogs do use their big round eyes for more than just giving the puppy dog face. The eyes are a path of communication between dog and human that establishes are greater connection of understanding between the two. In this week’s article “A Simple Reason for a Big Difference: Wolves Do Not Look Back at Humans, but Dogs Do”, researchers from Eotvos University conduct a set of experiments in order to see the behavioral differences between dogs and socialized wolves when it came to communicating with humans, specifically through eye contact. It’s clear that there are huge behavioral differences between wolves and dogs, but what these experiments aim to do is to uncover whether this huge deviation in behavior all stems from how dogs and wolves perceive visual information from humans.

Study 1

In the first study, the wolves were tested from the age of 4 months, once a week for 7 months. The subjects underwent 20 trials total.

Two containers were set 1.5 m apart. Both had previously been rubbed down with meat, so as to minimize the influence of smell on the experiment.

Food (raw meat) was hidden in one of the bowls, switched around in the hands of the experimenter, then placed on the ground. The wolves were asked to choose between the two based on human gestures.

With each wolf, the experimenters tested the reaction to distal pointing, in which the human’s index finger is pointed about 50 cm away from the container. Then the wolves were tested using proximal pointing, meaning the finger of the human is only about 5-10 cm away from the container. Lastly, the wolves were asked to react to touching, more specifically, the human touches the container holding the food physically. The human gestured while making eye-contact with the subject before he was released, ad allowed to choose a container.

The order of the baiting was random, but the bowl that contained food was places an equal number of times on both the right and the left.

The data used was taken from the first and last 20 trials were analyzed, and a control group of 20 was also established (these wolves attempted to find the food without the involvement of human gestures).

Study 2
In the second study, 9 wolves and nine dogs were used. They were held 1.5 meters from two bins, one of which had a piece of meat inside that was placed there while the subject couldn’t see it. The subjects were first allowed to open the bin and find the food on their own, within a two minute period. Afterward, the dogs and wolves were allowed to do the same, but the bins were mechanically sealed, making them impossible to open.

This design was mimicked with a rope pulling exercise, where dogs pulled at a rope in a cage holding a piece of meat. In the first set of trials, the meat was obtainable, but in the second the rope was tied so pulling it would not move the meat, again within a two minute period.

These trials were recorded to note the latency, direction, and duration of “gazing”. That is, when the subject turned to look at the trainer standing a meter behind them.

Study 1: Results and Discussion
In Study 1 of this article, four socialized wolves were studied to see how they responded to human gestures and cues. The wolves were given a two-way object choice task and had to find the hidden food which was indicated by the human examiner using three different gestural cues. However, despite being raised similar to dogs and considered “socialized”, the wolves generally performed worse than dogs in similar testing situations and showed a wide range of individual differences.

The tests were done weekly over a seven-month period. The data of the first and last twenty trials were analyzed. The results of these trials were graphed. The wolves did the best at finding the hidden food when the human actually touched the object. They did second best when the gesture was proximal pointing. The wolves were the least successful at finding the hidden food when distal pointing was the cue. However within the data, there was a wide variation of scores among individual wolves. For example, one wolf did significantly better as the trials went on.

The authors of this study concluded that socialized wolves are able to learn about some human gestures when they are connected with food. From growing up being fed by humans, the wolves learned to associate the human hand with food. This knowledge helps the wolves find the hidden food more often when the gesture is proximal pointing (close to the object) or actual touching of the object. The scores were lower when the cue was distal pointing. The scientists concluded that this result was due to the fact that wolves do not look at humans and if they do, it is only for a very short time. To find the hidden food with the touching or proximal pointing cues, the wolves only needed to look around the area of the containers (objects) to see if the hand was close to it. In order for the wolves to read the distal pointing cue, they needed to look at the human’s upper body to see the direction of the pointing finger. Dogs, on the other hand, are able to do better in this problem situation because they prefer to look at their human owners which the scientists think is a behavior that begins communication.

On the PBS series, “Dogs That Changed the World”, biologist Raymond Coppinger, a professor of biology and animal behavior from Hampshire College in Massachusetts, shares his belief that socialized wolves can never be as tame as dogs. He has spent years working with dogs and tame wolves and has seen that they are not completely docile in the areas of food or breeding.

Miho Nagasawa, Kazutaka Mogi, and Takefumi Kikusui, professors at Azabu University in the Department of Animal Science and Biotechnology, studied the “Attachment Between Humans and Dogs”, particularly the dog’s visual cognitive ability. They researched, from a biological perspective, the special relationship dogs have developed with humans. They discovered that when dogs visually connect with their owners, their urinary oxytocin levels increase. They also revealed that when a dog interacted visually with their owner, as opposed to a stranger, their heart rate and variable heart rate increased. From their research, they found that when dogs experienced a problem, they would visually look at their human owners as if to communicate they needed help. In one study, it was demonstrated that dogs preferred to accept food from humans whose faces were visible rather than people who had their eyes covered. Visual cues, such as gazing, are very important in human relationships, such as the one between a mother and her infant. These researchers have concluded that the dog species has developed this visual cognitive ability in order to survive in a close symbiotic relationship with humans.

Another team of researchers at the Max Planck Institute for Evoluntionary Anthropology in Germany did a study entitled, “Making Inferences About the Location of Hidden Food: Social Dog, Causal Ape”. In this study dogs and apes had to locate hidden food and were given communicative, behavioral, or physical cues from the human examiner. Their results showed that dogs performed better than the apes when given communicative cues, such as pointing and looking. They concluded that dogs have become skilled at reading human behavior especially in visual communication skills because of the many years of domestication in human culture.

Study 2 Results and Discussion:
After training occurred to solve a simple manipulation task, when faced with an impossible problem, dogs looked and gazed at humans while wolves essentially ignored their presence. The key difference between the behavior of dogs and wolves is the dogs ability to look at the human face.

During the block test trials, there was no difference between the rate at which dogs and wolves could obtain the food during the training phase for both the bin opening and rope pulling trials. Yet, in both species, the mean latency for obtaining the reward decreased over six trials indicating that as the trials progressed, the reward was obtained more quickly. As shown by the figures below, the dogs looked back earlier and spent more time gazing at the humans than did the wolves in both tasks.

In the bin opening tasks, dogs spent a greater amount of time gazing at the humans and their first look at the human was significantly earlier in the trail than that of the wolves. Specifically, dogs looked towards humans for an average of 1 minute while trying to obtain the meat as compared to wolves who apparently ignored the human presence. Additionally the duration was longer and time at which dogs began face/eye contact was sooner than that of the socialized wolves.

Dogs were also more likely to interrupt their own efforts to obtain the reward. This indicated that dogs have a smaller incentive to go out of their way to gain the effects of food than wolves. The poorer performance of the socialized wolves overalls seems to be attributed to their decreased willingness to look or gaze at the humans. The willingness of the dogs or wolves to look at the human seems to be genetically determined and as demonstrated by this experiment is present in dogs, but not wolves.

Here is a video describing Human-dog interaction and relationship as discussed by Adam Miklosi, the author of this article:

As the article’s title suggests, dogs are generally more responsive to human cues compared to the socialized wolves. This responsiveness is due to their willingness to communicate with humans, through visual contact. As tasks got harder for both the dogs and wolves, there was an overwhelming difference in behavior between the two, as dogs looked towards the humans for support while wolves made no effort to communicate with the humans. This key difference in behavior is one of the keys to defining a domesticated dog and distinguishing them from other species. Most likely in earlier times, dogs that were able to communicate and obey better through visual contact were the ones that humans preferred and thus passed on their genes. This added dimensions of communication between human and dog through visual contact creates a bond that may explain why owners feel so in tune with “man’s best friend”. Next time your dog looks up at you with its “puppy dog eyes” just know that it’s aware of the fact that all it needs to do is look into your eyes to get its message across.

Works Cited
Brauer, J., Kaminski, J., Riedel, J., Call, J., and Tomasello, M. “Making Inferences About the Location of Hidden Food: Social Dog, Causal Ape”. 2006. Journal of Comparative Psychology. Vol. 120, No. 1, 38-47. 2006: American Psychological Association.

Mikiosi, A., Kubinyi, E., Topal, J., Gacsi, M., Viranyl, Z., and Csanyi, V. “A simple Reason for a Big Difference: Wolves Do Not Look Back at Humans, but Dogs Do”. April 29, 2003. Current Biology. Vol. 13, 763-766. 2003: Elseview Science Ltd.\

Nagasawa, M., Mogi, K., and Kikusui, T., “Attachment Between Humans and Dogs”. Japanese Psychological Research. 2009. Vol. 51, No.3, 209-221. 2009: Japanese Psychological Association, Blackwell Publishing Ltd.

“What caused the domestication of wolves?”. Dogs That Changed the World. Public Broadcasting Station series. 9/28/10 and 10/5/10. wolves/1276/

Categories: Domestication

A Simple Reason for a Big Difference (Wednesday)

October 26, 2010 16 comments


This study compares the communicative abilities of dogs and wolves. Both the dogs and the wolves examined in this study were socialized to humans and then observed as they interacted around the familiar humans. In the first study, we can see that socialized wolves were capable of finding hidden food as directed by their human experimenter. Although they were capable of doing this, the dogs exceeded their capability by superior results. In the next study, the dogs and wolves underwent training to solve a simple manipulation task and the results showed that the dogs continued to look to the humans for help, while the wolves did not. The main conclusions drawn from these two studies were the difference between dogs and wolves: the dogs have an ability to look at the human’s face. Looking behavior is essential for communication and certain interactions, not only between humans but also in the human-dog contact. The ability to look at a human face is probably due to positive feedback processes over the generations. Of course, like all other behavioral attributes, this is due to both evolution and environment. This study emphasizes the difference of looking behavior and communication between dogs and wolves.

Here is a YouTube video on facial signals and body language of a dog. This is interesting to take a look at and see the similarities between facial signals and body language of a human and facial signals and body language of a dog.

Do you think these are evolutionary or environmentally adapted? How come wolves don’t display the same type of body language or facial signals as humans?
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Categories: Domestication

Social Cognitive Evolution in Foxes (Thursday Class)

October 19, 2010 11 comments

Dogs are able to read human gestures better than wolves as well as other primates. This experiment tested to see if this ability was a by-product of domestication or if there was actually selection for this trait. Experimentally domesticated foxes were compared against dog puppies and other control group of foxes that were not bred to be tame to see which would be more responsive to human gestures and cues.

The experiment was done in several parts; the first involved comparing how the experimental domesticated foxes, dog puppies and the control group reacted to cues to find hidden food. The second part was to see how long it would take for each of the two fox groups to approach an object when a human was there versus when there was no human there. Another part involved seeing if foxes from either of the groups would touch a toy already touched by an object.

The results supported the idea that this type of sociocognitive learning in domestic dogs and experimentally domesticated foxes is a by-product that just comes with domestication. This was not a trait that required selection, but instead just happened to come with the process of domestication.

This is another article that discusses cognitive evolution between dogs and humans; it goes over the possibility that these types of similarities could be a result of convergent cognitive evolution. It discusses how domestication could result in changes in other various traits, like ability to read human gestures; there is also mention of Balyaev’s long continued experiment with domesticating foxes.
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Categories: Domestication