The dog, looking into the owner’s eyes, manipulates the level of oxytocin in his body
Welcome to the iCover Blog Pages ! The experiments of Japanese neurobiologists conducted in the outgoing 2015 allowed us to make an amazing conclusion: the formation of empathy between the owner and his dog is made possible thanks to the subtle mechanism of positive feedback, similar to that which occurs in the relationship between mother and child. It turned out that, unlike tamed wolves, dogs often seek to catch the owner’s eyes, which entails a marked increase in the last level of the neurohormone oxytocin, responsible for developing a sense of attachment, care and the formation of a positive emotional background. We will tell you more about the results of our research in our article today.
Most of us will agree that the dog is a friend of a person, but until recently we did not suspect how complex the communication mechanisms have been in the human-dog pair for millennia.
By the ability of effective communication with humans, dogs not only significantly surpass their closest wild relatives - wolves, but also managed to get ahead of our conditional relatives - chimpanzees. One of the parameters of such communication is the ability of a domestic dog to understand the meaning of the human gaze. Many human communication skills, including understanding of intonation and gaze, according to scientists, dogs were able to master during evolution. Researchers attribute this to the fact that individuals who better understand the mood and wishes of their owners had some selective advantages in the process of domestication.
Sharing information with one's eyes is one of the most ancient ways of communication that is characteristic of man and is responsible for the formation of an emotional connection between "your" people, in particular, between a mother and a child. Today it has already been proven that when the baby looks at the mother, the level of the hormone oxytocin in her brain and blood rises, thereby stimulating the manifestation of maternal affection and care. The consequence of the latter is an increase in the level of oxytocin in the hypothalamus of the child, which stimulates the latter to further consolidate the experience. So the mechanism of positive feedback in people is formed.
As research results have shown, a person’s attachment to his four-legged pets takes place both emotionally and at the neurological level. Scientists are convinced that the positive feedback maintained through the exchange of gazes into the eyes and at the level of oxytocinergic neural networks is one of the necessary factors in the formation and development of full-fledged relationships expressed in love and mutual understanding between mother and child. But can such perfect mechanisms of stimulation of such feedback, forming as intraspecific, develop in the relationship between the owner and his dog? And can oxytocin act as a catalyst for this process for both?
A group of Japanese neuroscientists took up the search for the answer to the second question. The results of recent experiments were published in the journal Science. Somewhat earlier, the same team of scientists experimentally proved that canine gaze is really able to increase the level of the neurohormone oxytocin in the host. During the experiment, the level of oxytocin in the urine of the host was measured before and after half an hour of communication with the dog. As it turned out, the longer the “session” was, during which the dog looked into the eyes of its owners, the greater the level of oxytocin was recorded in the owner at the end of the experiment.
A number of recent studies conducted in 2015 have answered the question of whether oxytocin levels in dogs increase. The experiment was attended by wolves, grown from the first years in the home environment. In total, 30 dogs of different breeds and 11 domesticated wolves with their owners took part in the study. As in the first case, the level of oxytocin (this time with four-legged friends) was measured before and after the experiment. The half-hour stay of the owners and their pets was filmed on video. It was forbidden to feed and give toys to animals, there were no other restrictions.
As in the results of previous studies, in the last experiments of the “man-dog” pair two groups were clearly identified: with weak and strong friendly ties. The last group included dogs, most often looking into the eyes of the owner and owners, focusing attention in questionnaires on affection for their wards. In the first group, the owners, on the contrary, showed restraint of emotions, and the dogs did not show much desire to catch the owner's eye.
In total, according to the results of the experiment, 21 pairs were identified in the second group, designated LG (long gaze - long look), and nine pairs in the first SG (short gaze, short look). Schematically, the results of the experiment are shown in the figure from an article in Science:
On the left is the time during which the dog looked into the eyes of the owner in the first five minutes of communication. Black bar - dogs that have the warmest relations with the owner (LG group), white - SG group; the gray column (whose height is zero and therefore not visible) - hand wolves that do not look at the owner in the eye at all. At the top right - the level of oxytocin in the host before and after the experiment, at the bottom right - the same in the body of a dog (or wolf).
The report said that LG dogs looked into the owner’s eyes for the longest time. The overwhelming majority of wolves did not do this, which is understandable, because for them, looking into the eyes is associated with a threat.
In the LG group, by the end of the experiment, the level of oxytocin increased significantly in humans, slightly less in their pets. In the SG group and in wolves with their owners, the level of oxytocin remained practically unchanged. Moreover, in the LG group (unlike the other two groups), a positive correlation was found between the duration of the dog's gaze and the increase in the level of oxytocin in humans and dogs.
Another important detail was noted: for other behavioral parameters that were recorded during the experiment (the owner’s conversation with the pet, the duration of the games and stroking), their relationship with the level of oxytocin was not so obvious, although those owners whose dogs looked at them longer often stroked their pets.
Thus, scientists came to an unambiguous conclusion: the dog, looking into the owner’s eyes, manipulates the level of oxytocin in his body (primarily in the blood and brain).
No less interesting were the results of the second experiment during which 27 pairs of subjects were divided, divided into two groups. Oxytocin was dripped into the dogs of one group and saline was administered to the dogs of the other group. After that, the dog was allowed into the room where the owner and two other people unfamiliar to her were nearby. In this case, people who were in the room, any external manifestations of attention (stroking, maintaining a conversation, foreign objects) that could affect the purity of the experiment were excluded. During the experiment, it turned out that the dogs that were injected with oxytocin looked at their owners longer than the representatives of the second group. At the same time, a similar dependence was clearly observed only in bitches, while pernasal administration of oxytocin had no effect on the behavior of males. one of the possible explanations is that the introduction of oxytocin stimulates in males not only the oxytocin, but also the vasopressin system, which controls aggressive and territorial behavior, which increases alertness to strangers. Interestingly, the tendency of the influence of oxytocin on behavior depending on gender is also significantly manifested in people.
The most interesting and significant result, according to the authors of the second experiment, was an increase in the level of oxytocin in the owners of bitches recorded after the end of a half-hour communication session, which, according to the conditions of the experiment, could not help touching or talking with their four-legged friends, communicating with them only at the level of gaze . In couples belonging to the group, dogs in which were not subjected to instillation of oxytocin, in the presence of strangers, no changes in the level of oxytocin were recorded in either the dogs or their owners.
The results of the experiments can be considered as a convincing argument in favor of the hypothesis of Japanese scientists: in the development and maintenance of mutual affection of a dog and a person, a positive feedback loop involving the neurohormone oxytocin, similar to that which causes the formation of mutual affection of mother and child, is actually involved. Evidence of the fact that such a connection does not arise between wolves and their owners indicates that the latter developed in dogs through domestication, and was not inherited from their wild ancestors.
Perhaps the development of such a tendency increased the chances of the distant ancestors of today's dogs to adapt to life among people.
In fact, dogs have learned to take advantage of the primordially human way of wordless communication that our ancestors developed to strengthen social ties.
Source: Miho Nagasawa, Shouhei Mitsui, Shiori En, Nobuyo Ohtani, Mitsuaki Ohta, Yasuo Sakuma, Tatsushi Onaka, Kazutaka Mogi, Takefumi Kikusui. Source // Science. 2015. V. 348. P. 333–336.
Dear readers, we are always happy to meet and wait for you on the pages of our blog. We are ready to continue to share with you the latest news, review articles and other publications and will try to do our best to make the time spent with us useful for you. And, of course, do not forget to subscribe to our columns . Our other articles and events
Most of us will agree that the dog is a friend of a person, but until recently we did not suspect how complex the communication mechanisms have been in the human-dog pair for millennia.
By the ability of effective communication with humans, dogs not only significantly surpass their closest wild relatives - wolves, but also managed to get ahead of our conditional relatives - chimpanzees. One of the parameters of such communication is the ability of a domestic dog to understand the meaning of the human gaze. Many human communication skills, including understanding of intonation and gaze, according to scientists, dogs were able to master during evolution. Researchers attribute this to the fact that individuals who better understand the mood and wishes of their owners had some selective advantages in the process of domestication.
Sharing information with one's eyes is one of the most ancient ways of communication that is characteristic of man and is responsible for the formation of an emotional connection between "your" people, in particular, between a mother and a child. Today it has already been proven that when the baby looks at the mother, the level of the hormone oxytocin in her brain and blood rises, thereby stimulating the manifestation of maternal affection and care. The consequence of the latter is an increase in the level of oxytocin in the hypothalamus of the child, which stimulates the latter to further consolidate the experience. So the mechanism of positive feedback in people is formed.
Experiments and their results
As research results have shown, a person’s attachment to his four-legged pets takes place both emotionally and at the neurological level. Scientists are convinced that the positive feedback maintained through the exchange of gazes into the eyes and at the level of oxytocinergic neural networks is one of the necessary factors in the formation and development of full-fledged relationships expressed in love and mutual understanding between mother and child. But can such perfect mechanisms of stimulation of such feedback, forming as intraspecific, develop in the relationship between the owner and his dog? And can oxytocin act as a catalyst for this process for both?
A group of Japanese neuroscientists took up the search for the answer to the second question. The results of recent experiments were published in the journal Science. Somewhat earlier, the same team of scientists experimentally proved that canine gaze is really able to increase the level of the neurohormone oxytocin in the host. During the experiment, the level of oxytocin in the urine of the host was measured before and after half an hour of communication with the dog. As it turned out, the longer the “session” was, during which the dog looked into the eyes of its owners, the greater the level of oxytocin was recorded in the owner at the end of the experiment.
A number of recent studies conducted in 2015 have answered the question of whether oxytocin levels in dogs increase. The experiment was attended by wolves, grown from the first years in the home environment. In total, 30 dogs of different breeds and 11 domesticated wolves with their owners took part in the study. As in the first case, the level of oxytocin (this time with four-legged friends) was measured before and after the experiment. The half-hour stay of the owners and their pets was filmed on video. It was forbidden to feed and give toys to animals, there were no other restrictions.
As in the results of previous studies, in the last experiments of the “man-dog” pair two groups were clearly identified: with weak and strong friendly ties. The last group included dogs, most often looking into the eyes of the owner and owners, focusing attention in questionnaires on affection for their wards. In the first group, the owners, on the contrary, showed restraint of emotions, and the dogs did not show much desire to catch the owner's eye.
In total, according to the results of the experiment, 21 pairs were identified in the second group, designated LG (long gaze - long look), and nine pairs in the first SG (short gaze, short look). Schematically, the results of the experiment are shown in the figure from an article in Science:
On the left is the time during which the dog looked into the eyes of the owner in the first five minutes of communication. Black bar - dogs that have the warmest relations with the owner (LG group), white - SG group; the gray column (whose height is zero and therefore not visible) - hand wolves that do not look at the owner in the eye at all. At the top right - the level of oxytocin in the host before and after the experiment, at the bottom right - the same in the body of a dog (or wolf).
The report said that LG dogs looked into the owner’s eyes for the longest time. The overwhelming majority of wolves did not do this, which is understandable, because for them, looking into the eyes is associated with a threat.
In the LG group, by the end of the experiment, the level of oxytocin increased significantly in humans, slightly less in their pets. In the SG group and in wolves with their owners, the level of oxytocin remained practically unchanged. Moreover, in the LG group (unlike the other two groups), a positive correlation was found between the duration of the dog's gaze and the increase in the level of oxytocin in humans and dogs.
Another important detail was noted: for other behavioral parameters that were recorded during the experiment (the owner’s conversation with the pet, the duration of the games and stroking), their relationship with the level of oxytocin was not so obvious, although those owners whose dogs looked at them longer often stroked their pets.
Thus, scientists came to an unambiguous conclusion: the dog, looking into the owner’s eyes, manipulates the level of oxytocin in his body (primarily in the blood and brain).
No less interesting were the results of the second experiment during which 27 pairs of subjects were divided, divided into two groups. Oxytocin was dripped into the dogs of one group and saline was administered to the dogs of the other group. After that, the dog was allowed into the room where the owner and two other people unfamiliar to her were nearby. In this case, people who were in the room, any external manifestations of attention (stroking, maintaining a conversation, foreign objects) that could affect the purity of the experiment were excluded. During the experiment, it turned out that the dogs that were injected with oxytocin looked at their owners longer than the representatives of the second group. At the same time, a similar dependence was clearly observed only in bitches, while pernasal administration of oxytocin had no effect on the behavior of males. one of the possible explanations is that the introduction of oxytocin stimulates in males not only the oxytocin, but also the vasopressin system, which controls aggressive and territorial behavior, which increases alertness to strangers. Interestingly, the tendency of the influence of oxytocin on behavior depending on gender is also significantly manifested in people.
The most interesting and significant result, according to the authors of the second experiment, was an increase in the level of oxytocin in the owners of bitches recorded after the end of a half-hour communication session, which, according to the conditions of the experiment, could not help touching or talking with their four-legged friends, communicating with them only at the level of gaze . In couples belonging to the group, dogs in which were not subjected to instillation of oxytocin, in the presence of strangers, no changes in the level of oxytocin were recorded in either the dogs or their owners.
The results of the experiments can be considered as a convincing argument in favor of the hypothesis of Japanese scientists: in the development and maintenance of mutual affection of a dog and a person, a positive feedback loop involving the neurohormone oxytocin, similar to that which causes the formation of mutual affection of mother and child, is actually involved. Evidence of the fact that such a connection does not arise between wolves and their owners indicates that the latter developed in dogs through domestication, and was not inherited from their wild ancestors.
Perhaps the development of such a tendency increased the chances of the distant ancestors of today's dogs to adapt to life among people.
In fact, dogs have learned to take advantage of the primordially human way of wordless communication that our ancestors developed to strengthen social ties.
Source: Miho Nagasawa, Shouhei Mitsui, Shiori En, Nobuyo Ohtani, Mitsuaki Ohta, Yasuo Sakuma, Tatsushi Onaka, Kazutaka Mogi, Takefumi Kikusui. Source // Science. 2015. V. 348. P. 333–336.
Dear readers, we are always happy to meet and wait for you on the pages of our blog. We are ready to continue to share with you the latest news, review articles and other publications and will try to do our best to make the time spent with us useful for you. And, of course, do not forget to subscribe to our columns . Our other articles and events