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The complex human environment results in a hard-to-bridge gap between human and animal studies on general cognitive abilities (g; colloquially often referred to as “intelligence”). Pet dogs are adapted to our environment, but a convincing demonstration ofgis missing. Exploratory and confirmatory factor analyses on seven tasks revealed a hierarchical structure with two cognitive domains (problem solving, learning) and an overarchingcanine g. Age did not affect the structure.Canine gwas negatively linked to age, height, and the owner’s emotional attitude but positively to training level, activity/excitability trait, experienced trauma and normal body condition. The longitudinal analyses over three years differentiated three main trajectory clusters: declining, stable, improving. The diversity of ageing phenotypes supports dogs’ translational value ingfactor and ageing research.One-Sentence SummaryThecanine gfactor is linked to age, height, training level, personality, body condition, and owner’s attitude.

For a long time, oxytocin has been thought to have a generally positive effect on social cognition and prosocial behavior; however, recent results suggested that oxytocin has beneficial effects only under certain conditions. The aim of the present study was to explore potential associations between social competence and the effect of intranasal oxytocin on the social behavior of laboratory beagle dogs. We expected oxytocin treatment to have a more pronounced positive effect on dogs with lower baseline performance in a social test battery. Thirty-six adult dogs of both sexes received 32 IU intranasal oxytocin and physiological saline (placebo) treatment in a double-blind, cross-over design, with 17-20 days between the two sessions. Forty minutes after the treatment, dogs participated in a social test battery consisting of eight situations. The situations were carried out within one session and took 20-30 min to complete. Principal component analysis on the coded behaviors identified four components (Willingness to interact, Preference for social contact, Non-aversive response to nonsocial threat, and Non-aversive response to social threat). The subjects' behavior during the placebo condition was used to assess their baseline performance. We found that oxytocin treatment had a differential effect on the behavior depending on the baseline performance of the individuals in all components, but only two treatment × baseline performance interactions remained significant in a less sensitive analysis. In accordance with our hypothesis, oxytocin administration increased dogs' contact seeking and affiliative behaviors toward humans but only for those with low baseline performance. Dogs with low baseline performance also showed significantly more positive (friendly) reactions to social threat after oxytocin administration than after placebo, while for dogs with high baseline performance, oxytocin administration led to a more negative (fearful) reaction. These results indicate that similar to those on humans, the effects of oxytocin on dogs' social behavior are not universally positive but are constrained by individual characteristics and the context. Nevertheless, oxytocin administration has the potential to improve the social behavior of laboratory beagle dogs that are socially less proficient when interacting with humans, which could have both applied and animal welfare implications.

The dog (Canis familiaris) has been proposed as a model of numerous human psychiatric diseases, including autism spectrum disorder (ASD). A recent account of the mechanisms underlying autistic behaviour in humans suggests that the core social symptoms of autism are rooted in impaired social motivation. Here we aimed to investigate the plausibility of this motivational explanation in dogs – that is, to study whether a decrease in social motivation (specifically, in the attentional weight assigned to social stimuli) is related to ASD-like behaviours in dogs. Based on the diagnostic criteria of ASD, we have developed a questionnaire (Interspecific Social Responsiveness Survey – ISRS) to assess those aspects of social skills in dogs that may relate to ASD-like behaviours. Analysis of the responses was carried out using a sample of 1343 dogs, and the exploratory factor analysis of the 26 items produced a three-factor solution accounting for 41.3% of the variance. A subsample of subjects (N = 20 adult dogs with varying ISRS scores) were then trained to use a touchscreen in a visual cue-response association task. During the test phase, dogs had to perform the same motor task (nose poke response) while exposed to non-social and social distracting stimuli (10 trials in a semi-random order). The behavioural performance of the dogs (measured by looking times and response latency) with different levels of social competence varied in terms of how they responded to the distracting stimuli. The pattern of results revealed that subjects with higher level of social competence showed a stronger distinction between the social and non-social distractors, manifesting in increased looking at the social (but task-irrelevant) stimulus and in reduced orientation toward the touchscreen. Our findings correspond with those previously found in human ASD studies, and further confirm the idea that domestic dogs represent a promising model for the study of human-analogue forms of social-motivational deficits.

Human faces play a special role in social cognition, since as a core signal of interpersonal communication, they convey various kinds of information (e.g., about sex, age, race, emotions, intentions). Study 1 aimed to explore how this specialization manifests itself in eye movements when looking at neutral, static, female faces. We monitored the gaze pattern of 23 adult participants using eye-tracking method. To test if template-driven processes are involved in face perception, and to see how inversion affects fixations on special facial stimuli, we presented vertically cut half-faces in upright and inverted positions (so half of each stimulus represented a half-face, whereas the other half was left blank). Our results corroborate prior findings consistently demonstrating the dominance of the triangular area marked by the eyes and the mouth, measured by the number and duration of fixations. In addition, we found evidence for so-called complementary fixations, targeted at the non-informative parts (i.e., the half that does not contain any facial information) of the pictures, suggesting that other mechanisms beyond purely stimulus-driven ones might drive looking behavior when scanning faces. Study 2 was intended to test if these systematic eye movements are face-specific or occur in case of other visual objects as well.

It has been suggested that the way in which owners interact with their dogs can largely vary and influence the dog-owner bond, but very few objective studies, so far, have addressed how the owner interacts with the dog. The goal of the present study was to record dog owners' interaction styles by means of objective observation and coding. The experiment included eight standardized situations in which owners of pet dogs were asked to perform specific tasks including both positive (i.e. playing, teaching a new task, showing a preference towards an object in a food searching task, greeting after separation) and potentially distressing tasks (i.e. physical restriction during DNA sampling, putting a T-shirt onto the dog, giving basic obedience commands while the dog was distracted). The video recordings were coded off-line using a specifically designed coding scheme including scores for communication, social support, warmth, enthusiasm, and play style, as well as frequency of behaviors like petting, praising, commands, and attention sounds. Exploratory Factor Analysis of the 20 variables measured revealed 3 factors, labeled as Owner Warmth, Owner Social Support, and Owner Control, which can be viewed as analogues to parenting style dimensions. The experimental procedure introduced here represents the first standardized measure of interaction styles of dog owners. The methodology presented here is a useful tool to investigate individual variation in the interaction style of pet dog owners that can be used to explain differences in the dog-human relationship, dogs' behavioral outcomes, and dogs stress coping strategies, all crucial elements both from a theoretical and applied point of view.

a b s t r a c t Several types of questionnaires are in use to measure fear-related behaviour in family dogs. Our aim was to develop a general questionnaire based on relevant previous studies in order to facilitate the standardization of measurements of fear-related behaviour in dogs (social fear, non-social fear, separation problems, anxiety/destructiveness and neuroticism). We investigated which aspects of fear do emerge as distinct factors when measuring fear in dogs with our consensus questionnaire. We developed the questionnaire by piercing together seven discrete fear-related factors from six previous studies representing different aspects of fear. Our final questionnaire consisted of 56 items and was filled out by 833 Hungarian pet dog owners. Principal component analysis was applied to explore the factorial structure of the ques- tionnaire scores. The original seven factors used in developing the questionnaire did not emerged as discrete factors. Instead, we found four factors (33 questionnaire items) labeled as neuroticism (CRA = 0.87), dog-directed fear (CRA = 0.84), human-directed fear (CRA = 0.90) and separation-related behavior (CRA = 0.83). The effects of demographic and dog keeping characteristics on these factors were also tested by generalized linear models (GLMs). For example, toy dogs had a higher risk to show neuroticism and dog-directed fear. Female owners were more frequently reporting human-directed fear in their dogs. Female dogs showed higher level of dog-directed fear. Older dogs score was higher on neuroticism and neuroticism correlated with the time of acquisition.

[This corrects the article DOI: 10.1371/journal.pone.0195448.].

We describe the relationships between dog owners’ personality attributes (assessed via questionnaire), their behaviours and the dog’s behaviours observed during brief dog-owner and dog-stranger interactions (N = 78). Interactions comprised the owner commanding the dog to sit, and the stranger showing a ball to the restrained dog and then hiding it. Owners scoring higher on neuroticism and openness used more commands (gestural and verbal) when asking the dog to sit, and the dogs of owners higher on neuroticism obeyed with a longer latency and spent more time looking at the stranger. More extraverted owners praised their dog more, and it took longer for their dogs to look at the stranger but they spent more time looking at the stranger, whereas dogs of more agreeable owners spent more time looking at the ball. Based on these results we conclude that some aspects of owners’ personality appear to be tied to their dog’s attentional concerns. Keywords: dog-human interaction; personality; multivariate statistical methods

Partner choice is strongly affected by similarity in physical and psychological characteristics. Although there is a popular belief that dogs share similar personality characteristics with their owners, no studies have yet addressed the topic. Here, we tested for associations between the dog and owner personality in two countries (Austria and Hungary) and found significant positive correlations between owners and their dogs in all the five investigated personality dimensions (neuroticism, extraversion, conscientiousness, agreeableness, and openness). This similarity could not be attributed solely to the owners’ self-projection, since the similarity in the first four dimensions was also significant when an independent peer person assessed the dog instead of the owner. The similarity was not affected by the length of ownership, however, we found cultural differences in the correlation pattern; more and stronger correlations were found in the Hungarian sample. Moreover, in multi-dog households the dogs’ similarity patterns complement each other, suggesting possible differences in the dogs’ role. Our results provide the first evidence that dogs do resemble their owners suggesting potential applied utility as well as indicating that dog–owner relationship could be a useful model of human social relationships.

Modern dog breeding has given rise to more than 400 breeds differing both in morphology and behaviour. Traditionally, kennel clubs have utilized an artificial category system based on the morphological similarity and historical function of each dog breed. Behavioural comparisons at the breed-group level produced ambiguous results as to whether the historical function still has an influence on the breed-typical behaviour. Recent genetic studies have uncovered genetic relatedness between dog breeds, which can be independent from their historical function and may offer an alternative explanation of behavioural differences among breeds. This exploratory study aimed to investigate the behaviour profiles of 98 breeds, and the behavioural differences among conventional breed groups based on historical utility and among genetic breed clusters. Owners of 5733 dogs (98 breeds) filled out an online questionnaire in German. Breed trait scores on trainability, boldness, calmness and dog sociability were calculated by averaging the scores of all individuals of the breed. Breeds were ranked on the four traits and a cluster analysis was performed to explore behavioural similarity between breeds. We found that two of the behaviour traits (trainability and boldness) significantly differed both among the conventional and the genetic breed groups. Using the conventional classification we revealed that Herding dogs were more trainable than Hounds, Working dogs, Toy dogs and Non-sporting dogs; Sporting dogs were also more trainable than Non-sporting dogs. In parallel, Terriers were bolder than Hounds and Herding dogs. Regarding genetic relatedness, breeds with ancient Asian or African origin (Ancient breeds) were less trainable than breeds in the Herding/sighthound cluster and the Hunting breeds. Breeds in the Mastiff/terrier cluster were bolder than the Ancient breeds, the breeds in the Herding/sighthound cluster and the Hunting breeds. Six breed clusters were created on the basis of behavioural similarity. All the conventional and genetic groups had representatives in at least three of these clusters. Thus, the behavioural breed clusters showed poor correspondence to both the functional and genetic categorisation, which may reflect the effect of recent selective processes. Behavioural breed clusters can provide a more reliable characterization of the breeds’ current typical behaviour.

Studies about the behaviours of mixed-breed dogs are rare, although mixed-breeds represent the majority of the world’s dog population. We have conducted two surveys to investigate the behavioural, demographic, and dog keeping differences between purebred and mixed-breed companion dogs. Questionnaire data were collected on a large sample of dogs living in Germany (N = 7,700 purebred dogs representing more than 200 breeds, and N = 7,691 mixed-breeds). We found that according to their owners, mixed-breeds were (1) less calm, (2) less sociable toward other dogs, and (3) showed more problematic behaviour than purebreds (p < 0.001 for all). Mixed-breeds and purebreds were similar in trainability and boldness scores. However, twelve out of 20 demographic and dog keeping factors differed between purebred and mixed-breed dogs, and two factors showed considerable (> 10%) differences: neutering was more frequent among mixed-breeds, and they were acquired at older ages than purebreds (p < 0.001 for both), which could result in the observed behaviour differences. After controlling for the distribution of the demographic and dog keeping factors, we found that mixed-breeds were (1) more trainable than purebreds, (2) less calm, and (3) showed more problematic behaviour than purebreds (p < 0.001 for all). We discuss that these differences at least partly might be due to selective forces. Our results suggest that instead of being the “average” dogs, mixed-breeds represent a special group with characteristic behavioural traits.

The study of dog personality has a long history. In this chapter, we present an overview of the concepts and methods applied to dog personality by reviewing the most recent experimental investigations. Several genetic and environmental factors have been identified that influence dogs’ personality. Understanding the underlying genetic and developmental mechanisms of the dog as a natural animal model for human social behaviour broadens our possibilities to rely on an experimental approach to personality. The research on genetic effects and gene–environment interaction may enable owners and trainers to choose genetically suitable individuals for specific environments.

The oxytocin system has a crucial role in human sociality; several results prove that polymorphisms of the oxytocin receptor gene are related to complex social behaviors in humans. Dogs' parallel evolution with humans and their adaptation to the human environment has made them a useful species to model human social interactions. Previous research indicates that dogs are eligible models for behavioral genetic research, as well. Based on these previous findings, our research investigated associations between human directed social behaviors and two newly described (−212AG, 19131AG) and one known (rs8679684) single nucleotide polymorphisms (SNPs) in the regulatory regions (5′ and 3′ UTR) of the oxytocin receptor gene in German Shepherd (N = 104) and Border Collie (N = 103) dogs. Dogs' behavior traits have been estimated in a newly developed test series consisting of five episodes: Greeting by a stranger, Separation from the owner, Problem solving, Threatening approach, Hiding of the owner. Buccal samples were collected and DNA was isolated using standard protocols. SNPs in the 3′ and 5′ UTR regions were analyzed by polymerase chain reaction based techniques followed by subsequent electrophoresis analysis. The gene–behavior association analysis suggests that oxytocin receptor gene polymorphisms have an impact in both breeds on (i) proximity seeking towards an unfamiliar person, as well as their owner, and on (ii) how friendly dogs behave towards strangers, although the mediating molecular regulatory mechanisms are yet unknown. Based on these results, we conclude that similarly to humans, the social behavior of dogs towards humans is influenced by the oxytocin system.

Research using the two-object choice paradigm showed that dogs prefer the object associated with the happy human emotion. However, they provided rather ambiguous results regarding the negative emotions. We assumed that differences between the dogs’ and owners’ interest towards the ‘negative’ object might be responsible for this. In our experiment, dogs observed their owner expressing different emotions towards two uniform plastic bottles. Five dog groups were tested based on the condition they received: (1) happy versus neutral, (2) happy versus disgust, (3) neutral versus disgust and (4–5) neutral vs neutral, as control groups. Contrary to previous studies using free choice paradigm, we used a task-driven approach. After the demonstration, the dogs had to retrieve one object to the owner. The dogs’ performance in the two neutral–neutral groups did not differ from the chance level. In contrast, subjects were able to distinguish between the happy and neutral expression of the owner: they both approached and fetched the ‘happy’ object. In the happy–disgusted and neutral–disgusted groups, the dogs approached the bottles randomly, suggesting that they found the ‘disgusting’ and ‘neutral’ objects equally attractive. Nevertheless, the dogs preferentially retrieved the object marked with the relatively more positive emotion (happy or neutral) to the owner in both conditions. Our results demonstrate that dogs are able to recognize which is the more positive among two emotions, and in a fetching task situation, they override their own interest in the ‘disgusting’ object and retrieve what the owner prefers.

Recent research has shown that dogs' possess surprisingly sophisticated human-like social communication skills compared to wolves or chimpanzees. The effects of domestication on the emergence of socio-cognitive skills, however, are still highly debated. One way to investigate this is to compare socialized individuals from closely related domestic and wild species. In the present study we tested domestic ferrets (Mustela furo) and compared their performance to a group of wild Mustela hybrids and to domestic dogs (Canis familiaris). We found that, in contrast to wild Mustela hybrids, both domestic ferrets and dogs tolerated eye-contact for a longer time when facing their owners versus the experimenter and they showed a preference in a two- way choice task towards their owners. Furthermore, domestic ferrets, unlike the wild hybrids, were able to follow human directional gestures (sustained touching; momentary pointing) and could reach the success rate of dogs. Our study provides the first evidence that domestic ferrets, in a certain sense, are more dog-like than their wild counterparts. These findings support the hypothesis that domestic species may share basic socio-cognitive skills that enable them to engage in effectively orchestrated social interactions with humans.

Giulia Cimarelli1,2,*, Borbala Turcsan1, Zsofia Banlaki3, Friederike Range1,2, Zsolt Ronai3, Maria SasvariSzekely3, Zsofia Viranyi1,2 1 Clever Dog Lab, Messerli Research Institute, University of Veterinary Medicine, Vienna, Medical University of Vienna, University of Vienna, Vienna, Austria 2 Wolf Science Center, Ernstbrunn, Austria 3Department of Medical Chemistry, Molecular Biology and Pathobiochemistry, Semmelweis University, Budapest, Hungary

Clever Dog Lab, Nussgasse 4, 1090 Vienna, Austria*Corresponding author: Phone: (361) 381-2179; borbala.turcsan@gmail.comPersonality matching in owner-dog dyads is relativelyunderstudied. The current research takes a cross-speciesapproach to investigate the relationship between the person-alitytraitsoftheownersandoftheirdogsandtheassociationbetween ‘‘relationship satisfaction’’ and dog/owner person-ality traits. 120 adult owners with one dog were asked to fillout two personality questionnaires and to rate their relation-ship with their dog on a 10-point scale. We compared theowners’ and the dogs’ personality assessment in extraver-sion, neuroticism, agreeableness and openness traits usingSpearman rank order correlations. Univariate GLM wasusedtoexaminetheeffectsofthehumananddogpersonalitytraits on the relationship satisfaction. Significant positivecorrelations were found between the owners’ and dogs’ per-sonality assessment in neuroticism and extraversion. Therelationship satisfaction reported by the owner was relatedonly to the dogs’ personality traits (neuroticism, extraver-sion), none of the human traits were associated with it.However, the assessment of the dog’s personality may bebiased by the owners’ tendency to project their own charac-teristics onto their dogs. To address this issue, we asked 26owners with more than one dog to assess both their firstand second dog. Owners assessed their first dog similarlytothemselvesinneuroticism,butthecorrelationinextraver-sion was not significant. In the case of the second dog, thecorrelation in neuroticism was negative, while in extraver-sion it was positive. However, the first and second dog didnot differ from each other in either personality traits. Thesefindings support that owners do not project indiscriminatelytheir own characteristics onto their dogs. Our results showa convergence between the neuroticism and extraversiontraits of dogs and their owners, which might be related tothenumberofdogsinthehouseholdandtheorderofacquir-ing the dogs.Key words: personality; owner-dog dyads; relationshipsatisfaction

In dogs, the social and spatial restriction associated with living in a kennel environment could lead to chronic stress and the development of abnormal behaviors (“kennel-dog syndrome”). However, little is known about how kenneled dogs differ from their conspecifics living as pets in human families. In the current study, using a test battery exposing the dogs to novel stimuli, we compared the behavior of three groups of beagles: (1) kenneled dogs living in a restricted environment with limited human contact (N = 78), (2) family dogs living in human families as pets (N = 37), and (3) adopted dogs born in the kenneled population but raised in human families (N = 13). We found one factor comprising most of the test behaviors, labeled as Responsiveness. Family dogs and adopted dogs scored higher in Responsiveness than kenneled dogs. However, 23% of the kenneled dogs were comparable to family and adopted dogs based on a cluster analysis, indicating a similar (positive) reaction to novel stimuli, while 77% of the kenneled dogs were unresponsive (mostly immobile) in at least part of the test. To assess if the behavioral difference between the family and kenneled dogs could be due to genetic divergence of these two populations and/or to lower genetic diversity of the kenneled dogs, we analyzed their genetic structure using 11 microsatellite markers. We found no significant difference between the populations in their genetic diversity (i.e., heterozygosity, level of inbreeding), nor any evidence that the family and kenneled populations originated from different genetic pools. Thus, the behavior difference between the groups more likely reflects a G × E interaction, that is, the influence of specific genetic variants manifesting under specific environmental conditions (kennel life). Nevertheless, some kenneled individuals were (genetically) more resistant to social and environmental deprivation. Selecting for such animals could strongly improve the welfare of kenneled dog populations. Moreover, exploring the genetic background of their higher resilience could also help to better understand the genetics behind stress- and fear-related behaviors.

The aim of this study was to analyze the relationships between four personality traits (calmness, trainability, dog sociability and boldness) of dogs (Canis familiaris) and dog and owner demographics on a large sample size with 14,004 individuals. German speaking dog owners could characterize their dog by filling out a form on the Internet. There were five demographic variables for dogs and nine for owners. Two statistical methods were used for investigating the associations between personality and demographic traits: the more traditional general linear methods and regression trees that are ideal for analyzing nonlinear relationships in the structure of the data. The results showed that calmness is influenced primarily by the dog’s age, the neutered status, the number of different types of professional training courses (e.g. obedience, agility) the dog had experienced and the age of acquisition. The least calm dogs were less than 2.5 years old, neutered and acquired after the first 12 weeks of age, while the calmest dogs were older than 6.9 years. Trainability was affected primarily by the training experiences, the dog’s age, and the purpose of keeping the dog. The least trainable dogs had not received professional training at all and were older than 3 years. The most trainable dogs were those who participated in three or more types of professional training. Sociability toward conspecifics was mainly determined by the age, sex, training experience and time spent together. The least sociable dogs were older than 4.8 years and the owners spent less than 3 h with the dog daily. The most sociable dogs were less than 1.5 years old. Males were less sociable toward their conspecifics than females. Boldness was affected by the sex and age of the dog and the age of acquisition. The least bold were females acquired after the age of 1 year or bred by the owner. The boldest dogs were males, acquired before the age of 12 weeks, and were younger than 2 years old. Other variables, including the owner’s gender, age, education, previous experience with dogs, the number of people and dogs in the household, and purpose of keeping the dogs had minor, but detectable effects. The results suggest that on-line questionnaires are a very effective means for collecting data about dog behavior, especially if owners are motivated by instant feedback. However, note that the characteristics of dogs in the present study were reported by the owners, and the associations with the traits do not necessarily represent a causal relationship.

Non-REM bursts of activity in the sigma range (9–16 Hz) typical of sleep spindles predict learning in dogs, similar to humans and rats. Little is known, however, about the age-related changes in amplitude, density (spindles/minute) and frequency (waves/second) of canine spindles. We investigated a large sample (N = 155) of intact and neutered pet dogs of both sexes, varying in breed and age, searching for spindles in segments of non-REM sleep. We recorded EEG from both a frontal midline electrode (Fz) and a central midline electrode (Cz) in 55.5% of the dogs, in the remaining animals only the Fz electrode was active (bipolar derivation). A similar topography was observed for fast (≥13 Hz) spindle occurrence as in humans (fast spindle number, density on Cz > Fz). For fast spindles, density was higher in females, and increased with age. These effects were more pronounced among intact animals and on Fz. Slow spindle density declined and fast spindle frequency increased with age on Cz, while on Fz age-related amplitude decline was observed. The frequency of fast spindles on Fz and slow spindles on Cz was linked to both sex and neutering, suggesting modulation by sexual hormones. Intact females displayed higher frequencies than males and neutered females. Our findings support the argument that sigma bursts in the canine non-REM sleep are analogous to human sleep spindles, and suggest that slow and fast spindles display different trajectories related to age, of which an increase in frontal fast spindles is unique to dogs.

In humans, age-related changes in personality occur in a non-random fashion with respect to their direction, timing, and magnitude. In dogs, there are still gaps in our knowledge about the detailed dynamics of age-related personality changes. We analysed the personality of 217 Border collies aged from 0.5 to 15 years both cross-sectionally and longitudinally using a test battery, to specify age periods when changes most prominently occur, assess the magnitude of changes, and analyse individual differences in personality change. We found that similar to humans, changes in personality occur unevenly during the dogs’ life course, however, their dynamics seems to be specific for each trait. Activity-independence decreased mostly from puppyhood (0.5–1 years) to adolescence (> 1–2 years), then continued to decrease in a slowing rate. Novelty seeking did not change markedly until middle age (> 3–6 years), then showed a steady linear decrease. Problem orientation increased strongly until middle age then showed no marked changes in later age periods. We also revealed individual differences in personality change over time, and showed that a few individuals with potential age-related impairments significantly affected the general age trajectory of some traits. These results raise caution against the over-generalisation of global age trends in dogs.