Dog Breed Differences in Visual Communication with Humans

Socio-economic evaluation of human-dog coexistence: A 40,000 years history

The human-animal relationship and its benefits have been a popular issue in recent decades. This study focuses on the dog as a paradigmatic example of this complex bond. The relationship between human and dog evolved over thousands of years through the domestication process. During this period, climatic, cultural, geographical and social changes have had a direct impact on this bond. Dogs have a remarkable capacity to play a variety of roles that mirror the evolution of human societies. Subsequently, questions arise regarding the important and symbolic roles that canines played in ancient cultures, religions and mythological traditions. Specifically, how have these roles changed through history? This research aimed to explore the socio-economic aspects of the human-dog relationship, spanning from ancient civilizations to modern societies. Through a systematic search methodology, this investigation seeks to provide insights into the dynamics of the complex human-dog relationship, including historical backgrounds, socio-cultural dynamics, economic implications and associated challenges. Additionally, the present study addresses the environmental concerns that emerge alongside rising stray dog populations. This research emphasizes the importance of strategies to balance the benefits of this coexistence that promote human and animal welfare.

Cooperative but Dependent-Functional Breed Selection in Dogs Influences Human-Directed Gazing in a Difficult Object-Manipulation Task

It is still largely unknown to what extent domestication, ancestry, or recent functional selection are responsible for the behavioral differences in whether dogs look back to a human when presented with a difficult task. Here, we tested whether this ubiquitous human-related response of companion dogs would appear differently in subjects that were selected for either cooperative or independent work tasks. We tested N = 71 dogs from 18 cooperative and 18 independent breeds. Subjects learned in a five-trial warming-up phase that they could easily obtain the reward from a container. In trial six, the reward became impossible to take out from the locked container. When the task was easy, both breed groups behaved similarly, and their readiness to approach the container did not differ between the last 'solvable' and the subsequent 'unsolvable' trial. Task focus, looking at the container, touching the container for the first time, or interacting with the container with a paw or nose did not differ between the breed groups, indicating that their persistence in problem solving was similar. However, in the 'unsolvable' trial, cooperative dogs alternated their gaze more often between the container and the humans than the independent dogs did. The frequency of looking back was also higher in cooperative dogs than in the independent breeds. These are the first empirical results that suggest, in a balanced, representative sample of breeds, that the selection for different levels of cooperativity in working dogs could also affect their human-dependent behavior in a generic problem-solving situation.

Behavioural differences and similarities between dog breeds: proposing an ecologically valid approach for canine behavioural research

The behaviour of dogs holds great relevance for not only scientists from fundamental and applied research areas, but also due to the widespread roles of dogs in our societies as companions and working animals; their behaviour is also an important factor in animal and human welfare. A large proportion of dogs currently under human supervision belong to one of roughly 400 recognised breeds. Dog breeds can be characterised by distinctive, predictable and reproducible features, including some of their behavioural traits. To the scientist, the comparative analysis of the behaviour of dog breeds provides an opportunity for investigating an array of intriguing phenomena within an easily accessible model organism created from natural and human-driven evolutionary processes. There are many ways to design and conduct breed-related behavioural investigations, but such endeavours should always be based around biologically relevant research questions and lead to ecologically valid conclusions. In this review, we surveyed recent research efforts that included dog behaviour-related comparisons and applied a critical evaluation according to their methods of breed choice and the subsequent research design. Our aim was to assess whether these two fundamentally important components of experimental design provide a solid basis to reach valid conclusions. Based on 97 publications that fulfilled our selection criteria, we identified three primary methods used by researchers to select breeds for their investigations: (i) convenience sampling; (ii) hypothesis-driven, ancestry-based sampling; and (iii) hypothesis-driven, functional sampling. By using the SWOT (Strengths, Weaknesses, Opportunities, Threats) evaluation system, we highlight each of these techniques' merits and shortcomings. We identify when particular methods may be inherently unable to produce biologically meaningful results due to a mismatch between breed choice and the initial research goals. We hope that our evaluation will help researchers adopt best practices in experimental design regarding future dog breed comparisons.

Attachment-like behavioral expressions to humans in puppies are related to oxytocin and cortisol: A comparative study of Akitas and Labrador Retrievers

This study investigated the relationship between urinary hormone concentrations and attachment-related behaviors in two dog breeds, the Akitas and Labrador Retrievers, to elucidate the hormonal and behavioral mechanisms underlying domestication and interspecies attachment to humans. By measuring cortisol and oxytocin concentrations, and conducting the Strange Situation Test (SST), we aimed to investigate breed differences in endocrine secretions associated with domestication and how these differences influence dog behavior toward humans. Our results showed significant breed differences in urinary cortisol concentrations, with Akitas exhibiting higher levels than Labrador Retrievers. This suggests a breed-specific stress response related to genetic proximity to wolves. However, oxytocin concentrations did not differ significantly, which suggests a complex interplay between factors influencing the domestication process and the formation of attachment behaviors. Behavioral observations during the SST revealed breed-specific patterns, with Labrador Retrievers showing more playful and attachment-like behaviors and Akitas showing more exploratory and passive behaviors. The study found correlations between hormones and behaviors within breeds, particularly in Labrador Retrievers, where oxytocin concentrations were associated with attachment-like behaviors, and cortisol concentrations reflected individual differences in physical activity rather than stress responses to social situations. These findings contribute to the understanding of the evolutionary and adaptive processes underlying the ability of domestic dogs to form close relationships with humans while highlighting the role of hormonal mechanisms in mediating attachment behaviors and the influence of breed-specific genetic backgrounds on these processes.

Screen interaction behavior in companion dogs: results from a dog owner survey

Despite availability of video content marketed for dog (Canis familiaris) entertainment, there is little information on dog behaviors when viewing content, nor describing which content is engaging. The aims of this study were to define demographics of dogs that engage with screens, owner observed behaviors, and perceived content interest. A digital survey was distributed to dog owners (03/2022-03/2023). We collected demographics, home environment, owner-rated behaviors, content interest, and interest in 4 presented videos. We compared the representation of dogs from different purebred dog groups (categorized by job/purpose by the American Kennel Club) with the estimated general purebred dog population. Most respondents (total n=1,246) lived in the USA (89%). Median age was 4 years, 54% were purebred, 51% were female. Most (86%, n=1,077) stated their dog watched screen content. Excitement behaviors were often described: 78% of dogs approached the screen, 76% vocalized. Many owners played videos for their dogs when left alone. Dogs most frequently engaged with animal content; dogs were the most popular animal. Age and visual status influenced the frequency of perceived interaction; age and breed influenced content interest. Within purebred dogs that were stated to watch content, there was a relative over-representation of "sporting" and "herding"-type breeds. A dog's age, visual status, and breed type may influence their interest in video content at home. Because many owners reported excitement in their dogs in reaction to screen content, owners may wish to determine whether video content would be suitable for use when their dogs are left alone.

Would You Detour with Me? Association between Functional Breed Selection and Social Learning in Dogs Sheds Light on Elements of Dog-Human Cooperation

Interspecific social learning is a main synchronizing mechanism that enables dogs to adapt to the anthropogenic niche. It is not known whether dogs in general possess the capacity of learning from humans or whether more recent selective events have affected their ability to learn from humans. We hypothesized that cooperative and independent working dog breeds may behave differently in a social learning task. Dogs (N = 78 from 16 cooperative and 18 independent breeds) had to detour a transparent, V-shaped wire mesh fence. The experiment consisted of three one-minute-long trials. The control condition did not include a demonstration. In the demonstration condition, the experimenter placed a reward in the inside corner by walking around the fence. Cooperative dogs reached the target significantly faster, while independent dogs did not detour faster in trials 2 and 3 after the human demonstration. Detour latencies were not associated with the keeping conditions and training level of the subjects. As we assembled both test groups from several genetically distantly related breeds, we can exclude the explanation that higher cooperativity emerged only in particular clades of dogs; instead, functional selection for particular working tasks could enhance capacities that affect a wide range of socio-cognitive traits in dogs.

Genetic distance from wolves affects family dogs' reactions towards howls

Domestication dramatically changes behaviour, including communication, as seen in the case of dogs (Canis familiaris) and wolves (Canis lupus). We tested the hypothesis that domestication may affect an ancient, shared communication form of canids, the howling which seems to have higher individual variation in dogs: the perception and usage of howls may be affected by the genetic relatedness of the breeds to their last common ancestor with wolves ('root distance') and by other individual features like age, sex, and reproductive status. We exposed 68 purebred dogs to wolf howl playbacks and recorded their responses. We identified an interaction between root distance and age on the dogs' vocal and behavioural responses: older dogs from more ancient breeds responded longer with howls and showed more stress behaviours. Our results suggest that domestication impacts vocal behaviour significantly: disintegrating howling, a central, species-specific communication form of canids and gradually eradicating it from dogs' repertoire.

When the owner does not know: comparing puppies and adult dogs' showing behavior

Domestic dogs have been shown to engage in interspecific communication with their owners using a flexible repertoire of signals (i.e., gaze, vocalizations, and postures). This ability is influenced by ontogenetic development as well as breed selection. Different aspects of this phenomenon have been studied using the out of reach/hidden object task in which a piece of food is shown to the dog and then hidden in an unreachable spot by the experimenter. Dogs' behavioral displays toward the target and the owner (ignorant about the location of the food) have been observed. The complex communicative behavior dogs exhibit in this context is defined as showing behavior and includes attention-getting components directed toward the owner, and directional components directed toward the target. No study has investigated the ontogenetic development of this behavior. In the current study, we compared the showing behavior in 4-6 month old puppies and 2-11 year old adults in an out of reach task involving the hiding of a food reward in one of two cabinets. Dogs were exposed to three conditions: (1) Owner with Food (OF), (2) Owner No Food (ONF), and (3) Alone with food (AF). Dogs showed more gaze alternations when both the food and the owner were present confirming the intentional and referential nature of this behavior. Contrary to our expectations, we found no differences between the showing behaviors of 4-6 month old puppies and adult dogs. This study provides interesting preliminary evidence of showing behavior in puppies. Further studies are needed to gain a deeper understanding of the factors influencing this communicative behavior (i.e., breed, level of training). Furthermore, longitudinal studies should be performed from the age of 2 months up to 1 and 2 years to better clarify the influence of development and experience on showing behavior in domestic dogs.

Breed differences in social cognition, inhibitory control, and spatial problem-solving ability in the domestic dog (Canis familiaris)

The extraordinary genetic and behavioural diversity of dog breeds provides a unique opportunity for investigating the heritability of cognitive traits, such as problem-solving ability, social cognition, inhibitory control, and memory. Previous studies have mainly investigated cognitive differences between breed groups, and information on individual dog breeds is scarce. As a result, findings are often contradictory and inconsistent. The aim of this study was to provide more clarity on between-breed differences of cognitive traits in dogs. We examined the performance of 13 dog breeds (N = 1002 dogs) in a standardized test battery. Significant breed differences were found for understanding of human communicative gestures, following a human's misleading gesture, spatial problem-solving ability in a V-detour task, inhibitory control in a cylinder test, and persistence and human-directed behaviour during an unsolvable task. Breeds also differed significantly in their behaviour towards an unfamiliar person, activity level, and exploration of a novel environment. No significant differences were identified in tasks measuring memory or logical reasoning. Breed differences thus emerged mainly in tasks measuring social cognition, problem-solving, and inhibitory control. Our results suggest that these traits may have come under diversifying artificial selection in different breeds. These results provide a deeper understanding on breed-specific traits in dogs.

Disentangling help-seeking and giving up: differential human-directed gazing by dogs in a modified unsolvable task paradigm

Dogs are renowned for 'looking back' at humans when confronted with a problem, but it has been questioned whether this implies help-seeking or giving up. We tested 56 pet dogs from two breed groups (herding dogs and terriers) in a modified unsolvable task paradigm. One reward type (food or toy) was enclosed in a box, while the respective other reward was accessible. With both reward types, human-directed gazing in relation to the box was significantly positively correlated with interaction with the box, as long as an alternative was available. This suggests that both behaviours served to attain the unavailable reward and reflected individual motivation for the inaccessible vs the accessible reward. Furthermore, we varied whether the owner or the experimenter was responsible for handling the rewards. In the owner-responsible group, dogs rarely gazed at the experimenter. In the experimenter-responsible group, dogs preferentially directed box-related gazing (prior to or after looking at or interacting with the box) at the owner. Still, they gazed at the experimenter significantly longer than the owner-responsible group. Conversely, toy-related gazing was directed significantly more at the experimenter. Thus, dogs adjust their gazing behaviour according to the people's responsibility and their current goal (help-seeking vs play). Gaze duration did not differ between herding dogs and terriers. We conclude that dogs use gazing at humans' faces as a social problem-solving strategy, but not all gazing can be classified as such. Dogs' human-directed gazing is influenced by the social relationships with the persons, situational associations, and context (unsolvable problem vs play).

Persistence and gazing at humans during an unsolvable task in dogs: The influence of ownership duration, living situation, and prior experience with humans

The experiences that domestic dogs have with humans take many forms. We hypothesized that more experience with humans would lead to greater dependence on humans in problem-solving situations. We used the unsolvable task to compare persistence and gazing in dogs with differing degrees of experience with humans: 1) dogs living in a home for a year or more; 2) dogs living in a home for less than a year (including foster dogs); and 3) shelter dogs. Dogs first learned a solvable task; we then measured persistence as well as gazing at humans when the task was unsolvable. Dogs living in a home for a year or more gazed sooner and longer than shelter dogs. Formally trained dogs from breeders also gazed sooner than formally trained dogs from shelters. There were no differences in overall persistence among the three types of dog. However, shelter dogs spent more time biting the box and gazing at it than dogs in the home. Former shelter dogs, former strays, and dogs that had no formal training also spent more time biting the box. We conclude that ownership duration, background, and prior experiences with humans influence human-directed communication and persistence behaviors in dogs.

Canine Smell Preferences—Do Dogs Have Their Favorite Scents?

Simple Summary

There are many products that are targeted to pet owners. One category of these products is dog repellents—strongly aromatized solutions designed to stop dogs from approaching and investigating particular areas; the second are cosmetics which should be pleasant for dogs. Dogs have a particularly sensitive sense of smell; therefore, strong scents may be very intense, and not always pleasant, stimuli. It is truly interesting, then, that canine cosmetic products often have very strong fragrances designed mostly to appeal to the dog owners, rather than to the dogs themselves. Indeed, the scents that dogs choose to put on their fur differ strongly from those of common cosmetics. Dogs choose mostly intense, animal-derived smells, such as feces or carcasses, so there is a need to differentiate between canine and human smell preferences. As there is limited scientific data related to canine smell preferences, the purpose of this study was to verify dogs’ reactions to selected scents, which can also be appealing to humans. Our study shows that dogs were more likely to interact with the scents of blueberry, blackberry, mint, rose, lavender, and linalol.

Abstract

The available evidence on dogs’ scent preferences is quite limited. The purpose of this study was to verify the canine response to selected odors that may also be preferred by humans. The experiment was performed using 14 adult dogs (10 female and 4 male) of different breeds, body size, and age (1–14 years). During the experiment, dogs were exposed to 33 odor samples: a neutral sample containing pure dipropylene glycol (control) and 32 samples containing dipropylene glycol and fragrance oils. The dog was brought to the experimental area by its handler, who then stopped at the entrance, unleashed the dog, and remained in the starting position. The dog freely explored the area for 30 s. All dog movements and behavior were recorded and analyzed. The methodology of observing the dogs freely exploring the experimental area allowed us to determine the smells that were the most attractive to them (food, beaver clothing). Our study shows that dogs interacted more frequently with the scents of blueberries, blackberries, mint, rose, lavender, and linalol.

Breed group differences in the unsolvable problem task: herding dogs prefer their owner, while solitary hunting dogs seek stranger proximity

The communicating skills of dogs are well documented and especially their contact-seeking behaviours towards humans. The aim of this study was to use the unsolvable problem paradigm to investigate differences between breed groups in their contact-seeking behaviours towards their owner and a stranger. Twenty-four dogs of ancient breeds, 58 herding dogs, and 17 solitary hunting dogs were included in the study, and their behaviour when presented with an unsolvable problem task (UPT) was recorded for 3 min. All breed groups interacted with the test apparatus the same amount of time, but the herding dogs showed a longer gaze duration towards their owner compared to the other groups and they also preferred to interact with their owner instead of a stranger. Interestingly, the solitary hunting dogs were more in stranger proximity than the other groups, and they also showed a preference to make contact with a stranger instead of their owner. Hence, we found differences in contact-seeking behaviours, reflecting the dog–human relationship, between breed groups that might not only be related to their genetic similarity to wolves, but also due to the specific breeding history of the dogs.

Effect of different experiences with humans in dogs' visual communication

Dogs are particularly skillful in communicating with humans, and growing evidence points towards the importance of both species intertwined evolutionary history and intense daily partnership. Gaze alternation is a communicative behavior used by dogs from a very young age and is affected by factors such as aging and experience. We analyzed how different degrees of daily human interaction affect dogs' gazing behavior in the unsolvable task, where a desired food becomes inaccessible. Three groups with different degrees of daily exposure to humans were compared: pet dogs that live inside the house, pet dogs that live outside the house, and shelter dogs. We found no difference in latency to the first gaze, but pet dogs did show a higher proportion of individuals engaging in gaze alternation, a higher number of gaze alternations, and a longer duration of gaze than shelter dogs. Additionally, dogs living inside the house gazed more at the experimenter than dogs living outside. Overall, our results indicate a strong influence of experience over the development and use of these communicative behaviors in dogs, with groups that are closer to people in their daily lives being more willing to communicate with humans as a strategy to obtain a desired goal.

Effect of Sex and Reproductive Status on Inhibitory Control and Social Cognition in the Domestic Dog (Canis familiaris)

Simple Summary

Various behavioral differences exist between male and female dogs, but very little research has focused on how sex influences cognition. Even fewer studies have taken sex hormones into account. Our aim was to investigate whether dogs’ sex and neutering status can influence two important cognitive traits: inhibitory control and social cognition. Inhibitory control was assessed using the cylinder test. In this task, the dog is required to inhibit reaching for a treat directly through a transparent barrier, and instead go around the barrier to access the treat. Social cognition was assessed using the unsolvable task, during which a food reward is visible but impossible to access. Dogs have three opportunities for action in this situation: (a) persisting with the problem independently, (b) seeking attention from a human, or (c) abandoning the task. Males were more impulsive and independent compared to females, whereas females had greater inhibitory control and were more likely to gaze at a human during a problem-solving situation. Since neutering status did not affect the results, it seems likely that these sex differences arose during early development and were not affected by levels of circulating sex hormones to a great extent.

Abstract

Sex differences in a variety of cognitive traits have long been reported in various species, including dogs. However, only a few canine studies have taken the possible effect of reproductive hormones into account. The aim of this study was to investigate the effects of sex and reproductive status of pet dogs (N = 1032) on two cognitive traits: inhibitory control and social cognition. Inhibitory control was assessed using the cylinder test, and the dogs’ tendency to initiate social contact with a human during a problem-solving situation was assessed using the unsolvable task. Female dogs had a significantly higher success rate in the cylinder test compared to males, and they spent significantly more time in human-directed behavior during the unsolvable task. In contrast, males spent significantly more time in independent behavior during the unsolvable task. Reproductive status had no significant effect on the results of the cylinder test or the unsolvable task. Our results showed that female dogs asked for more help/used a more cooperative strategy during a problem-solving situation and had greater inhibitory control compared to males. According to our results, it seems likely that these sex differences were not influenced to a large extent by reproductive hormones.

Herding Dogs

Herding is done predominantly by breeds developed over centuries to millennia specifically for that purpose. Working-level herding breed dogs are intense, high-drive dogs that will work despite severe illness or pain, thereby masking clues that they are ailing or the nature of their problem. The handler should recognize subtle changes that might signal ill health, and veterinarians should take an active role in training handlers on essential skills. Herding dogs typically work entirely outdoors in rural to wilderness environments with continuous exposure to other domestic animals and wildlife and may be affected by trauma, toxin exposure, infectious diseases, and parasitic infections.

Shorter headed dogs, visually cooperative breeds, younger and playful dogs form eye contact faster with an unfamiliar human

Forming eye contact is important in dog–human communication. In this study we measured what factors affect dogs’ propensity for forming eye contact with an experimenter. We investigated the effect of [1] cephalic index (head shape’s metric, indicator of higher visual acuity at the centre of the visual field), [2] breed function (visual cooperativeness), [3] age and [4] playfulness with strangers in 125 companion dogs. Cephalic index was measured individually and analysed as a continuous variable. Results showed that [1] dogs with a higher cephalic index (shorter head) established eye contact faster. Since cephalic index is highly variable even within a breed, using artificial head shape groups or breed average cephalic index values is not recommended. [2] Breed function also affected dogs’ performance: cooperative breeds and mongrels established eye contact faster than dogs from non-cooperative breeds. [3] Younger dogs formed eye contact faster than older ones. [4] More playful dogs formed eye contact faster. Our results suggest that several factors affect dogs’ interspecific attention, and therefore their visual communication ability.

A review of the unsolvable task in dog communication and cognition: comparing different methodologies

Communication between dogs and humans is a topic of growing interest, and the "unsolvable task" is a common method used to measure human-directed communication. In this task, dogs learn how to solve a problem to obtain a reward. After a fixed number of trials, the reward becomes impossible to access, arguably leading to communicative attempts from the dog. Although useful to observe dogs' communicative behaviors in a fairly naturalistic situation, the methodology varies among studies regarding apparatus, number of trials, and other factors. The proxies used, for instance, gaze duration or frequency of gaze alternation, also vary, and there are discrepancies and a debate regarding what the task actually measures. Therefore, in this study, we reviewed the usage of the unsolvable task in canids of the genus Canis, searching Web of Science and Scopus for the terms "dog*", "Canis", "dingo*", "wolf" or "wolves" in the title and "unsolvable task" or "impossible task" in the topic. We included thirty-five studies in this review and discussed their different methodologies and proxies, such as different apparatuses, number of solvable trials, and different interpretations of "looking back", pointing out how they can affect results and hinder comparisons. Lastly, we used current data to propose strategies to homogenize the use of this important paradigm, with an ethogram of possible behaviors and their interpretation and a predefined set of methodological aspects for future research.

Variability in Human-Animal Interaction Research

The field of Human-Animal Interaction (HAI) is plagued with mixed results. Some findings appear to indicate that interacting with a companion animal is beneficial for some aspect of human health and well-being, while other research outcomes are inconclusive or even indicate the opposite. The purpose of this paper is to take a closer look at this variability in research outcomes and to provide plausible explanations and potential remedies. Some of the reasons for mixed results are likely due to the wide variety of methodologies implemented, intermittent use of standardized measures and manualized protocols, variability in human and animal participants, and limited quantification of human-animal interactions or definitions of pet ownership. Variability in research outcomes is not unique to HAI and is, in fact, not uncommon in many more established fields such as psychology and medicine. However, the potential reasons for the variability may be linked to the unique nature of HAI in that, in its' simplest form, it involves two complex organisms, a human and an animal, interacting in dynamic ways. We argue that this complexity makes research in this field particularly challenging and requires a broad spectrum of theoretical and methodological considerations to improve rigor while ensuring the validity and reliability of conclusions drawn from study results.

The application of computer graphics processing in visual communication design

The purpose of this paper is to improve the existing computer graphics image processing technology, so that designers can produce more inspiration, improve the author’s ability to innovate. Based on the information in the field of graphics visual communication as the research object, through the elaboration of graphical information characteristics, development course, and the visual communication of computer graphical related, such as cognitive psychology, semiology theory research, analyzes the computer graphics into a kind of economic and effective way of conveying information, the significance of interface design for mobile media. Experiments demonstrate the unique advantages of graphics in the process of information transmission. In 2022, the market size of computer graphics and vision will expand to 755.5 million RMB. It can be known that the communication mode integrating information and graphics, as the future development trend, will also be applied to more fields and play a greater role.

Do dogs eavesdrop on human interactions in a helping situation?

Eavesdropping is the acquisition of information by observing third-party interactions. Considering dogs' (Canis lupus familiaris) dependence on humans, it would be beneficial for them to eavesdrop on human interactions to choose an appropriate partner to associate with. Previous studies have found that dogs preferred a human who acted generously or cooperatively towards another human over one who acted selfishly or non-cooperatively, however they often did not control for potential location biases. This study controlled for local enhancement and investigated whether dogs derive and act on information about unfamiliar humans through reputation-like inferences by observing third-party interactions. 42 dogs participated in the experiment, which consisted of an observation phase and a test phase. In the observation phase, the animals observed a human with a box of food ask for help to open it from two people-one was helpful and the other was not. The test phase consisted of the impossible task and a choice test. Half of the sample was tested in the experimental condition and the other half was tested in the side control condition, where the two people swapped positions before the test phase. The results of the impossible task showed that dogs only looked at the helpful person first when the people stayed on the same side as they did in the observation phase. In the choice test, dogs chose at random, regardless of whether the people stayed on the same side or swapped positions. Our findings provide tentative support for a local enhancement interpretation of eavesdropping.

Estimating the heritability of cognitive traits across dog breeds reveals highly heritable inhibitory control and communication factors

Trait heritability is necessary for evolution by both natural and artificial selection, yet we know little about the heritability of cognitive traits. Domestic dogs are a valuable study system for questions regarding the evolution of phenotypic diversity due to their extraordinary intraspecific variation. While previous studies have investigated morphological and behavioral variation across dog breeds, few studies have systematically assessed breed differences in cognition. We integrated data from Dognition.com-a citizen science project on dog cognition-with breed-averaged genetic data from published sources to estimate the among-breed heritability of cognitive traits using mixed models. The resulting dataset included 11 cognitive measures for 1508 adult dogs across 36 breeds. A factor analysis yielded four factors interpreted as reflecting inhibitory control, communication, memory, and physical reasoning. Narrow-sense among-breed heritability estimates-reflecting the proportion of cognitive variance attributable to additive genetic variation-revealed that scores on the inhibitory control and communication factors were highly heritable (inhibitory control: h² = 0.70; communication: h² = 0.39), while memory and physical reasoning were less heritable (memory: h² = 0.17; physical reasoning: h² = 0.21). Although the heritability of inhibitory control is partially explained by body weight, controlling for breed-average weight still yields a high heritability estimate (h² = 0.50), while other factors are minimally affected. Our results indicate that cognitive phenotypes in dogs covary with breed relatedness and suggest that cognitive traits have strong potential to undergo selection. The highest heritabilities were observed for inhibitory control and communication, both of which are hypothesized to have been altered by domestication.

Why do dogs look back at the human in an impossible task? Looking back behaviour may be over-interpreted

The impossible task paradigm has been extensively used to study the looking back behaviour in dogs. This behaviour is commonly considered a social problem-solving strategy: dogs facing an unsolvable task, soon give up and look back at the experimenter to ask for help. We aimed to test if the looking back in an impossible task does indeed represent a social problem-solving strategy. We used a modified version of the classic impossible task, in which the subjects simultaneously faced three possible and one impossible trials. Additionally, subjects were tested in four different conditions: social condition (with an unknown experimenter); asocial condition (subject alone); 'dummy' human condition (with a 'dummy' human); object condition (with a big sheet of cardboard). Finally, we compared two populations of dogs differing in their experience of receiving help from humans: 20 pet dogs tested in their houses and 31 free-ranging dogs tested in Morocco. We found that the pet dogs and free-ranging dogs had similar persistence in interacting with the impossible task in all conditions. Moreover, subjects looked back with similar latencies at the human, at the dummy human and at the object. Overall, pet dogs looked back longer at the human than free-ranging dogs. This could be interpreted as pet dogs being more attracted to humans and/or having a stronger association between humans and food than free-ranging dogs. Concluding, the looking back in an impossible task does not represent a problem-solving strategy. This behaviour seems rather linked to the subject's persistence, to the salience of the stimuli presented, and potentially to the past reinforcement history.

Effect of Canine Oxytocin Receptor Gene Polymorphism on the Successful Training of Drug Detection Dogs

Drug detection dogs can be trained to locate various prohibited drugs with targeted odors, and they play an important role in the interdiction of drug smuggling in human society. Recent studies provide the interesting hypothesis that the oxytocin system serves as a biological basis for co-evolution between dogs and humans. Here, we offer the new possibility that genetic variation of the canine oxytocin receptor (OXTR) gene may regulate the success of a dog's training to become a drug detection dog. A total of 340 Labrador Retriever dogs that were trained to be drug detection dogs in Japan were analyzed. We genotyped an exonic SNP (rs8679682) in the OXTR gene and compared the training success rate of dogs with different genotypes. We also asked dog trainers in the training facility to evaluate subjective personality assessment scores for each dog and examined how each dog's training success was related to those scores. A significant effect of the OXTR genotype on the success of the dogs' training was found, with a higher proportion of dogs carrying the C allele (T/C and C/C genotypes) being successful candidates than dogs carrying the T/T genotype. Dog personality scores of Training Focus (Factor 1) were positively correlated with an increased likelihood that a dog would successfully complete training. Although the molecular mechanism of the OXTR gene and its functional pathway related to dog behavior remains unknown, our findings suggest that canine OXTR gene variants may regulate individual differences between dogs in their responsiveness to training for drug detection.

Wolf-like or dog-like? A comparison of gazing behaviour across three dog breeds tested in their familiar environments

Human-directed gazing, a keystone in dog-human communication, has been suggested to derive from both domestication and breed selection. The influence of genetic similarity to wolves and selective pressures on human-directed gazing is still under debate. Here, we used the 'unsolvable task' to compare Czechoslovakian Wolfdogs (CWDs, a close-to-wolf breed), German Shepherd Dogs (GSDs) and Labrador Retrievers (LRs). In the 'solvable task', all dogs learned to obtain the reward; however, differently from GSDs and LRs, CWDs rarely gazed at humans. In the 'unsolvable task', CWDs gazed significantly less towards humans compared to LRs but not to GSDs. Although all dogs were similarly motivated to explore the apparatus, CWDs and GSDs spent a larger amount of time in manipulating it compared to LRs. A clear difference emerged in gazing at the experimenter versus owner. CWDs gazed preferentially towards the experimenter (the unfamiliar subject manipulating the food), GSDs towards their owners and LRs gazed at humans independently from their level of familiarity. In conclusion, it emerges that the artificial selection operated on CWDs produced a breed more similar to ancient breeds (more wolf-like due to a less-intense artificial selection) and not very human-oriented. The next step is to clarify GSDs' behaviour and better understand the genetic role of this breed in shaping CWDs' heterospecific behaviour.

A wolfdog point of view on the impossible task paradigm

To elucidate the role of domestication, we used the impossible task paradigm to test Czechoslovakian Wolfdogs with a known proportion of 'wolfblood' in their DNA and, as a control group for our subjects, we used German shepherd dogs. We hypothesized that the difference between wolves and domestic dogs is based on genetics and modified by obedience; if so, the looking back performance of the subject should be linked to its proportion of wolf-genes. To prove that, we observed 73 Czechoslovakian Wolfdogs, and 27 German shepherd dogs, and analysed their human-directed gazing behaviour during our test. Our apparatus consisted of a glass container placed upside down over a small amount of food. The test proceeded with three solvable trials, in which the subject could obtain the food by manipulating the container, followed by an unsolvable one in which the container was fixed onto the board. Our results suggest that there is no significant correlation between the probability of looking back in Czechoslovakian Wolfdogs and their proportion of 'wolf blood'. However, the probability of looking back was higher in German Shepherd dogs than in Czechoslovakian Wolfdogs (odds ratio = 9.1). German Shepherd dogs showed not only a higher frequency of looking back, but also the duration of their looks was longer.

Effects of breed group and development on dogs' willingness to follow a human misleading advice

The aim of this work was to investigate the effect of dog breed groups, i.e., primitive, hunting/herding and Mastiff like (Study 1) and development, i.e., 4-month-old puppies vs adults (Study 2) on a quantity discrimination task. The task consisted of three conditions: C1-dogs were asked to choose between a large and a small amount of food; C2-the same choice was presented and dogs could choose after having witnessed the experimenter favouring the small quantity. C3-similar to C2 but the plates had two equally small food quantities. Study 1 revealed that dogs in the hunting/herding group were significantly more likely than Mastiff-like group to choose the small quantity indicated by the person over the large one, although all dog groups chose the large quantity over the small when they had a free choice. These results are consistent with the hypothesis that hunting/herding breeds have been selected for working in cooperation with humans and thus may be more sensitive to human social communicative cues than other breeds. In Study 2, results showed that 4-month-old puppies performed at chance level in C1, whereas in C2 both adults and puppies conformed to the experimenter's choice. In C3, adults followed the experimenter significantly more than puppies, although puppies still followed the experimenter above chance. Overall, domestic dogs seem to rely heavily on social communicative cues from humans, even when the information contradicts their own perception. This tendency to respond to human social cues is present, although at a lesser extent already at 4 months.

Differences in persistence between dogs and wolves in an unsolvable task in the absence of humans

Despite being closely related, dogs perform worse than wolves in independent problem-solving tasks. These differences in problem-solving performance have been attributed to dogs’ greater reliance on humans, who are usually present when problem-solving tasks are presented. However, more fundamental motivational factors or behavioural traits such as persistence, motor diversity and neophobia may also be responsible for differences in task performance. Hence, to better understand what drives the differences between dogs’ and wolves’ problem-solving performance, it is essential to test them in the absence of humans. Here, we tested equally raised and kept dogs and wolves with two unsolvable tasks, a commonly used paradigm to study problem-solving behaviour in these species. Differently from previous studies, we ensured no humans were present in the testing situation. We also ensured that the task was unsolvable from the start, which eliminated the possibility that specific manipulative behaviours were reinforced. This allowed us to measure both persistence and motor diversity more accurately. In line with previous studies, we found wolves to be more persistent than dogs. We also found motor diversity to be linked to persistence and persistence to be linked to contact latency. Finally, subjects were consistent in their performance between the two tasks. These results suggest that fundamental differences in motivation to interact with objects drive the differences in the performance of dogs and wolves in problem-solving tasks. Since correlates of problem-solving success, that is persistence, neophobia, and motor diversity are influenced by a species’ ecology, our results support the socioecological hypothesis, which postulates that the different ecological niches of the two species (dogs have evolved to primarily be scavengers and thrive on and around human refuse, while wolves have evolved to primarily be group hunters and have a low hunting success rate) have, at least partly, shaped their behaviours.

Intranasal Oxytocin Treatment Increases Eye-Gaze Behavior toward the Owner in Ancient Japanese Dog Breeds

Dogs acquired unique cognitive abilities during domestication, which is thought to have contributed to the formation of the human-dog bond. In European breeds, but not in wolves, a dog’s gazing behavior plays an important role in affiliative interactions with humans and stimulates oxytocin secretion in both humans and dogs, which suggests that this interspecies oxytocin and gaze-mediated bonding was also acquired during domestication. In this study, we investigated whether Japanese breeds, which are classified as ancient breeds and are relatively close to wolves genetically, establish a bond with their owners through gazing behavior. The subject dogs were treated with either oxytocin or saline before the starting of the behavioral testing. We also evaluated physiological changes in the owners during mutual gazing by analyzing their heart rate variability (HRV) and subsequent urinary oxytocin levels in both dogs and their owners. We found that oxytocin treatment enhanced the gazing behavior of Japanese dogs and increased their owners’ urinary oxytocin levels, as was seen with European breeds; however, the measured durations of skin contact and proximity to their owners were relatively low. In the owners’ HRV readings, inter-beat (R-R) intervals (RRI), the standard deviation of normal to normal inter-beat (R-R) intervals (SDNN), and the root mean square of successive heartbeat interval differences (RMSSD) were lower when the dogs were treated with oxytocin compared with saline. Furthermore, the owners of female dogs showed lower SDNN than the owners of male dogs. These results suggest that the owners of female Japanese dogs exhibit more tension during interactions, and apart from gazing behavior, the dogs may show sex differences in their interactions with humans as well. They also suggest that Japanese dogs use eye-gazing as an attachment behavior toward humans similar to European breeds; however, there is a disparity between the dog sexes when it comes to the owners’ oxytocin secretion. Japanese dogs also showed different attachment behaviors from both European breeds and wolves, and they likely use additional strategies to substitute gaze when forming the human–dog bond.

The role of domestication and experience in 'looking back' towards humans in an unsolvable task

A key element thought to have changed during domestication is dogs’ propensity to communicate with humans, particularly their inclination to gaze at them. A classic test to measure this is the ‘unsolvable task’, where after repeated successes in obtaining a reward by object-manipulation, the animal is confronted with an unsolvable version of the task. ‘Looking back’ at humans has been considered an expression of dogs seeking help. While it occurs more in dogs than in socialized wolves, the level of exposure to human communication also appears to play a role. We tested similarly raised adult wolves and mixed breed dogs, pet dogs and free-ranging dogs. Unlike previous studies, as well as species and levels of socialization, we included ‘persistence’ in trying to solve the task as a potential explanatory factor. Wolves were more persistent than all dog groups. Regardless of socialization or species, less persistent animals looked back sooner and longer. Free-ranging dogs, despite little exposure to dog-human communication, behaved similarly to other dogs. Together, results suggest that basic wolf-dog differences in motivation and exploration may override differences in human-directed behaviour when animals are equally socialized, and that once the human is considered a social partner, looking behaviour occurs easily.