Old dog, new tricks: Age differences in dog personality traits, associations with human personality traits, and links to important outcomes

Differential behavioral aging trajectories according to body size, expected lifespan, and head shape in dogs

The twofold life expectancy difference between dog breeds predicts differential behavioral and cognitive aging patterns between short- and long-lived dogs. To investigate this prediction, we conducted a cross-sectional analysis using survey data from over 15,000 dogs. We examined the effect of expected lifespan and three related factors (body size, head shape, and purebred status) on the age trajectory of various behavioral characteristics and the prevalence of canine cognitive dysfunction (CCD). Our findings reveal that, although age-related decline in most behavioral characteristics began around 10.5 years of age, the proportion of dogs considered "old" by their owners began to increase uniformly around 6 years of age. From the investigated factors, only body size had a systematic, although not gradual, impact on the aging trajectories of all behavioral characteristics. Dogs weighing over 30 kg exhibited an earlier onset of decline by 2-3 years and a slower rate of decline compared to smaller dogs, probably as a byproduct of their faster age-related physical decline. Larger sized dogs also showed a lower prevalence of CCD risk in their oldest age group, whereas smaller-sized dogs, dolichocephalic breeds, and purebreds had a higher CCD risk prevalence. The identification of differential behavioral and cognitive aging trajectories across dog groups, and the observed associations between body size and the onset, rate, and degree of cognitive decline in dogs have significant translational implications for human aging research, providing valuable insights into the interplay between morphology, physiological ageing, and cognitive decline, and unravelling the trade-off between longevity and relative healthspan.

The Perks of Pet Ownership? The Effects of Pet Ownership on Well-Being During the COVID-19 Pandemic

Pet ownership has often been lauded as a protective factor for well-being, particularly during the COVID-19 pandemic. We expanded this question to consider how pet (i.e., species, number) and owner (i.e., pet relationship quality, personality, attachment orientations) characteristics affected the association between pet ownership and well-being in a pre-registered mixed method analysis of 767 people assessed three times in May 2020. In our qualitative analyses, pet owners listed both benefits and costs of pet ownership during the COVID-19 pandemic. In our quantitative analyses, we found that pet ownership was not reliably associated with well-being. Furthermore, this association largely did not depend on the number of pets owned, the species of pet(s) owned, the quality of the human-pet relationship, or the owner's psychological characteristics. Our findings are consistent with a large body of research showing null associations of pet ownership on well-being (quantitatively) but positive reports of pet ownership (qualitatively).

Unsupervised Domain Adaptation for Mitigating Sensor Variability and Interspecies Heterogeneity in Animal Activity Recognition

Animal activity recognition (AAR) using wearable sensor data has gained significant attention due to its applications in monitoring and understanding animal behavior. However, two major challenges hinder the development of robust AAR models: domain variability and the difficulty of obtaining labeled datasets. To address this issue, this study intensively investigates the impact of unsupervised domain adaptation (UDA) for AAR. We compared three distinct types of UDA techniques: minimizing divergence-based, adversarial-based, and reconstruction-based approaches. By leveraging UDA, AAR classifiers enable the model to learn domain-invariant features, allowing classifiers trained on the source domain to perform well on the target domain without labels. We evaluated the effectiveness of UDA techniques using dog movement sensor data and additional data from horses. The application of UDA across sensor positions (neck and back), sizes (middle-sized and large-sized), and gender (female and male) within the dog data, as well as across species (dog and horses), exhibits significant improvements in the classification performance and reduced the domain discrepancy. The results highlight the potential of UDA to mitigate the domain shift and enhance AAR in various settings and for different animal species, providing valuable insights for practical applications in real-world scenarios where labeled data is scarce.

"An Aid with Soul"-Understanding the Determinants of Guide Dog-Owner Compatibility from Qualitative Interviews

Guide dogs hold the potential to increase confidence and independence in visually impaired individuals. However, the success of the partnership between a guide dog and its handler depends on various factors, including the compatibility between the dog and the handler. Here, we conducted interviews with 21 guide dog owners to explore determinants of compatibility between the dog and the owner. Experienced compatibility between the dog and the owner was associated with positive relationship aspects such as feeling secure with the dog. Certain characteristics emerged as subjective determinants of compatibility, including shared hobbies, high levels of openness in both or only the dog, similar activity levels and higher activeness in dogs, similar expressions of calmness; happiness; greediness; friendliness; and a complementary dominance-submissiveness relationship. Owners who perceived themselves to be similar in their personality to their dogs often reported to have a strong bond, to feel secure with their dog and to be less influenced by previous relationships. However, our results suggest that a strong bond between the dog and the owner does not exclusively yield positive effects. Moreover, prior dog ownership seems to have a potentially strong impact on the subsequent relationship. Our results contribute to the understanding of dog-owner compatibility and may improve the matching process of guide dogs and their prospective handlers.

Breed, age, and social environment are associated with personality traits in dogs

Personality in pets and other domesticated animals is important for their well-being and it can also influence human-animal relationships. Genetic and environmental factors influencing unwanted behavior in dogs are somewhat well known, but the factors influencing dog personality remain understudied. Here we examined environmental and demographic factors associated with seven broad personality traits in a survey of over 11,000 dogs. We utilized linear models and extensive model validation to examine the factors that have the most significant influences on personality and calculated effect sizes to assess the importance of these variables. Breed and age had the strongest associations with dog personality traits. Some environmental factors, especially puppyhood socialization, were also associated with personality. All factors had small effect sizes, highlighting that a lot of variation in personality remains unexplained. Our results indicate that personality traits are complex and strikingly similar in dogs, humans, and other nonhuman animals.

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.

A comparison of personality traits of gifted word learner and typical border collies

While personality and cognition are distinct domains, some personality traits may affect the capacity for problem-solving. It was suggested that there is a positive association between the Playfulness trait and problem-solving performance in humans. Studies on giftedness (extremely good capacity in the case of a specific skill), typically aimed to reveal the genetic, experiential, and mental origins of such extreme inter-individual variation. We exploited recent findings on giftedness in a specific cognitive skill, object label learning, in dogs to explore the potential association between this exceptional skill and personality traits. We administered the Dog Personality Questionnaire to 21 gifted dog owners and compared the personality traits of their dogs to those of matched samples of 43 Hungarian and 101 Austrian typical dogs, i.e., dogs lacking this exceptional capacity. Since most Gifted Word Learner dogs are Border collies, we restricted our analysis to dogs of this breed. We hypothesized that the Gifted Word Learner dogs may show higher levels of Playfulness. As expected, we found that the gifted Border collies were rated as more playful than both the Hungarian and Austrian typical ones. Our results suggest that an extremely high level of Playfulness is associated with giftedness in a specific cognitive trait in dogs: the capacity to learn object verbal labels, thus opening new possibilities for comparative research on the relationship between giftedness and personality.

Personality traits associate with behavioral problems in pet dogs

Personality traits, especially neuroticism, strongly predict psychopathology. The domestic dog (Canis lupus familiaris Linnaeus, 1758) is used as a natural model for psychiatric disorders, but the similarity between dog and human personality and the association between dog personality and unwanted behavioral traits, such as fearfulness, aggressiveness, and impulsivity/inattention, remain unknown. This study utilized structural equation modeling (SEM) with survey data of 11,360 dogs to examine the associations and correlations between seven personality and ten unwanted behavioral traits. Personality traits included insecurity, energy, training focus, aggressiveness/dominance, human sociability, dog sociability, and perseverance. Unwanted behavioral traits included fearfulness, noise sensitivity, fear of surfaces/heights, separation anxiety, barking, stranger-directed aggression, owner-directed aggression, dog-directed aggression, hyperactivity/impulsivity, and inattention. We first fitted confirmatory factor models for the unwanted behavioral traits and the best model grouped unwanted behaviors into four latent traits: fear-related behavior, fear-aggression, aggression, and impulsivity/inattention and used this structure in the subsequent SEM model. Especially, insecurity, which resembles the human neuroticism trait, was strongly associated with unwanted behavior, paralleling the association between neuroticism and psychopathology. Similarly, training focus, resembling conscientiousness, was negatively related to impulsivity/inattention, and aggressiveness/dominance was associated with aggressive behaviors, resembling associations of conscientiousness and agreeableness with attention deficit hyperactivity disorder and aggression-related psychopathology, respectively. These results indicate that dog personality traits resemble human personality traits, suggesting that their neurological and genetic basis may also be similar and making the dog a suitable animal model for human behavior and psychiatric disorders.

Size, skull shape and age influence the temperament of domestic dogs

Studies have investigated the relationship between dogs' morphological characteristics and behavioural dimensions, but little is discussed about this relationship in the context of dogs' responses to emotion eliciting stimuli and temperament. Based on the assumption that the developmental trajectory of behaviour and emotion processing is impacted by the interaction between organisms and environment, we analysed whether dogs' characteristics - that determine how they perceive and interact with their surroundings - affect temperament profiles. We looked at size, height, weight, skull morphology, age, sex, reproductive status, and breed of a sample of Brazilian domestic dogs' and their temperament (measured as Positive and Negative Activation), obtained via the PANAS questionnaire for dogs. We tested possible main effects and first-order interactions in linear mixed models. Younger dogs showed higher positive activation (i.e. sensitivity to positive stimuli; play and treats). For short snouted dogs, the older the dog, less was the negative activation (i.e. sensitivity to negative stimuli; punishment). And for long snouted dogs, larger dogs showed lower negative activation. Weight alone also showed an effect, with heavier dogs having less sensitivity to negative stimuli. Overall, our study demonstrated how morphology and age are important factors that influence temperament expression and emotional reactivity in dogs.

How Old Is My Dog? Identification of Rational Age Groupings in Pet Dogs Based Upon Normative Age-Linked Processes

Behavioral development is a lifelong process where cognitive traits such as learning and memory may be expected to take quadratic or linear trajectories. It is common practice for operational purposes to reduce study subjects into chronological categories when conducting research. However, there are no agreed-upon thresholds for this practice, and the lack of standardization may hinder comparison between studies of normative and pathological aging. In this perspective review, chronological categories have been identified that can be considered to represent normative cognitive and neurological aging in domestic family dogs. These categories work to capture age-related developmental trajectories for the majority of dog breeds. It is encouraged that researchers studying cognition and behavior, pathological cognitive deficits, or welfare of dogs across age categories utilize the categories presented here to best enable comparison between studies. The proposed groups could also support education programs informing owners of what behavioral changes to expect in their dog as they age, but they cannot be used to reflect health-based needs associated with breed-specific morbidity. The use of the age categories proposed here highlights significant welfare issues for breeds with the shortest average lifespans (e.g., the Great Dane). Studies show no evidence of an increased rate of behavioral or cognitive aging in short-lived breeds, and the shortest-lived breeds are most likely to die when classified by the proposed categories as Mature Adults. Adoption of these chronological categories in future research would aid comparison between studies and identification of non-normative age-related pathologies.

Owner Personality, Owner-Dog Attachment, and Canine Demographics Influence Treatment Outcomes in Canine Behavioral Medicine Cases

Human and canine parameters can affect the development of canine behavior problems, although their influence on the dog's response to veterinary behavioral treatment remains unclear. This study aimed to investigate the possible associations between canine behavior following clinical intervention and canine demographic characteristics, owner personality and owner-dog attachment. The study included 131 dog-owner dyads who attended a veterinary behavioral service. Owners completed the C-BARQ at baseline, 3-months and 6-months, and the 10 Item Personality Inventory and Lexington Attachment to Pet Scale at baseline. Data were analyzed for the effect of clinical intervention on C-BARQ subscale scores using mixed effect models. Binary logistic regression models were used to analyze the association between behavior change and canine and owner parameters. Within 6-months of veterinary consultation, trainability increased (coefficient 0.03, p = 0.01) and chasing (coefficient −0.04, p = 0.02), separation-related behavior (coefficient −0.04, p = 0.01) and energy level (coefficient −0.04, p = 0.05) decreased. Treatment outcomes were associated with both canine and owner variables. Canine behavior at baseline was the most consistent predictor of behavior change with less desirable baseline behavior associated with greater odds of decreased problem behavior at three- and 6-months post-consultation across most C-BARQ subscales. Canine age and weight; owner conscientiousness, extraversion and openness; and owner-dog attachment were also associated with treatment outcomes for some behavioral categories. These findings could be used by veterinarians to formulate more accurate prognoses and provide owners with targeted advice to reduce the influence of background factors on the dog's response to clinical behavioral intervention.

Dog and owner characteristics predict training success

Teaching owners how to train their dogs is an important part of maintaining the health and safety of dogs and people. Yet we do not know what behavioral characteristics of dogs and their owners are relevant to dog training or if owner cognitive abilities play a role in training success. The aim of this study is to determine which characteristics of both dogs and owners predict success in completing the American Kennel Club Canine Good Citizen training program. Before the first session of a dog training course, owners completed surveys evaluating the behavior and cognition of their dog and themselves. Additionally, we collected the dogs' initial training levels via behavioral tasks. We then examined what factors predicted whether the dogs passed the Canine Good Citizen test after the class ended. In terms of dog characteristics, we found that, while dog age, sex and neuter status did not predict success, owner-rated levels of disobedience did predict completion of the program. In terms of owner characteristics, owners who scored higher on cognitive measures were more likely to have their dogs complete the program. Finally, dog-owner characteristics such as the time spent training predicted success. Thus, characteristics of the dogs, owners, and how they interact seem to predict training success. These findings suggest that there are some owner, dog, and dog-owner characteristics that can facilitate or hinder dog training.

Individual and group level personality change across the lifespan in 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.

Behavioural and cognitive changes in aged pet dogs: No effects of an enriched diet and lifelong training

Dogs demonstrate behavioural changes and cognitive decline during aging. Compared to laboratory dogs, little is known about aging in pet dogs exposed to different environments and nutrition. In this study, we examined the effects of age, an enriched diet and lifelong training on different behavioural and cognitive measures in 119 pet dogs (>6yrs). Dogs were maintained on either an enriched diet or a control diet for one year. Lifelong training was calculated using a questionnaire where owners filled in their dog's training experiences to date. Before commencing the diet and after one year of dietary treatment, they were tested in the Modified Vienna Canine Cognitive Battery (MVCCB) consisting of 11 subtests to examine correlated individual differences in a set of tasks measuring general, social and physical cognition and related behaviours. Fourty two behavioural variables were coded and were subjected to principle component analyses for variable reduction. Twelve subtest level components and two Z-transformed variables were subjected to exploratory factor analysis which resulted in six final factors: Problem solving, Trainability, Sociability, Boldness, Activity-independence and Dependency. Problem solving, Sociability, Boldness, and Dependency showed a linear decline with age, suggesting that the MVCCB can be used as a tool to measure behavioural and cognitive decline in aged pet dogs. An enriched diet and lifelong training had no effect on these factors, calling attention to the fact that the real world impact of nutritional and other interventions in possibly counteracting the effects of aging, should be further investigated in pet dogs living under diverse conditions, in order to understand their ultimate effects.

Dogs' Sociability, Owners' Neuroticism and Attachment Style to Pets as Predictors of Dog Aggression

Simple Summary

It is widely known that psychological characteristics, for example personality traits, can facilitate the occurrence of aggressive behavior. Using the combination of two research methods—questionnaires and behavioral testing—we investigated the associations between a dog’s personality and its aggression towards humans and animals. Due to the close relationship and co-habitation of dogs and humans, we also looked at how the owner’s personality and the dog–human emotional bond, known as attachment style, play a role in dog aggression. Our results indicated that dogs which were aggressive towards humans were less sociable, and had owners who were less emotionally stable, more distant, and less clingy and controlling, compared to non-aggressive dogs. These results emphasize the importance of owner attachment to a dog for dog behavior, and may serve as a foundation for future research on psychosocial factors influencing dog aggression.

Abstract

A dog’s aggressive behavior is influenced by external and internal factors, including its psychological profile. In this study, dogs’ and owners’ personalities and the owners’ attachment style to their dogs were identified and associated with owner-reported dog aggression towards humans and animals. Forty Slovenian owners participated with their dogs, of different breeds and aggression history, sorted into three groups (non-aggressive dogs, dogs aggressive towards humans, and dogs aggressive towards animals). The owners filled out three separate questionnaires that assessed dog aggression history towards different targets, owner’s personality and degree of insecure attachment styles to dogs; namely anxious and avoidant attachment. Dog personality was characterized using a standardized dog mentality assessment test, during which the dog was exposed to nine tasks, performed outside, and dogs were scored based on behaviors they exhibited. The results indicated that dogs which were aggressive towards humans were less sociable than non-aggressive dogs and this was associated with the higher neuroticism scores of their owners. We also found that dogs which were aggressive towards strangers had owners with lower scores for anxious attachment and that dogs which were aggressive towards owners had owners with higher scores for avoidant attachment. These results imply that the psychological profiles of both a dog and its owner influence dog aggression towards humans.

Cross-Sectional Age Differences in Canine Personality Traits; Influence of Breed, Sex, Previous Trauma, and Dog Obedience Tasks

The dog has been suggested as a possible model for personality development over the lifespan, however, we know little about how aging may shape their personality or the magnitude of age-related changes. Previously we established that aging influences multiple dog demographics, which could also affect how personality traits change across different age periods. A demographic questionnaire and the Dog Personality Questionnaire were completed for a cross-sectional sample of 1,207 adult dogs living in Hungary (M_age = 7.71, SD = 4.12), split into six different age groups. Results revealed three of the five factors showed significant age effects. Activity/Excitability decreased with age, and whilst Responsiveness to training also decreased, only dogs older than 12 years differed significantly from the other groups. Aggressiveness toward animals showed a quadratic trajectory peaking in dogs aged 6–10 years. The greatest magnitude of age-related change was detected between late senior and geriatric ages, likely caused by compensatory behavioral changes to biological aging and owner attitudes to aging. When the models were re-run including the other explanatory variables, age group was no longer significant for the Responsiveness to training trait. The amount of time spent interacting/playing with the owner partially mediated the relationship between age and this trait, implying that interventions to increase play and training motivation may alleviate the negative effects of aging on dogs' trainability. Fifteen out of 28 explanatory variables were significantly associated with at least one of the five factors [weight, breed (pure/mixed breed), sex, off-leash activity, diet, previous trauma, age of dog when arrived in the household, play, dog training activities, number of known commands and dog obedience tasks]. Similarly to humans, dogs that had previously experienced trauma scored higher in fearfulness and aggression. A higher level of basic obedience was linked to some desirable dog personality traits (lower Fearfulness and Aggression, and higher Activity/Excitability and Responsiveness to training). Regardless of the direction of this relationship, obedience is an important aspect contributing to dog personality questionnaires and the dog-owner relationship. This study is unique in that it considered a wide variety of demographic variables which are influenced by aging.

Individual Differences in Response to Ambiguous Stimuli in a Modified Go/No-Go Paradigm are Associated with Personality in Family Dogs

Cognitive biases, often used as indices of affective and emotional states, are associated with individual differences in personality in humans and have been observed in nonhuman animals, including dogs. Although dogs have complementary advantages over traditional animal models of human cognition, little is known about the relationship between dogs’ cognitive bias and personality. Here, we examined in 29 family dogs (representing 14 breeds and 12 mutts; M_age = 4.59 years, SD = 2.90), the association between naturally occurring – as opposed to experimentally induced – cognitive bias, indexed via active choice behavior in a Go/No-Go (GNG) paradigm reflecting positive/negative expectations about ambiguous stimuli, and owner-rated personality. In a subsample we additionally assessed whether prior inhibition, personality, and inattention (IA)/hyperactivity/impulsivity (H/I) results could be replicated in a modified paradigm. We also explored whether expanding the response time-window would increase GNG errors and whether dogs exhibited differences in their behavioral approach to uncertainty. Findings indicated dogs with higher conscientiousness and extraversion scores were more likely to exhibit a “go” response to ambiguous stimuli. Replicability across prior and current results was generally established, e.g., as previously, IA did not predict GNG performance but extraversion did, whereas H/I predicted different indices of GNG performance. Increased response time-window did not result in differential performance, except for less commission errors. No differences in behavioral response strategy to trained “no-go” and to ambiguous stimuli were apparent. Results evince the dog is a promising animal model of the association between an optimistic cognitive bias and personality.

Homozygosity for Mobile Element Insertions Associated with WBSCR17 Could Predict Success in Assistance Dog Training Programs

Assistance dog training programs can see as many as 60% of their trainees dismissed. Many training programs utilize behavioral assays prior to admittance to identify likely successful candidates, yet such assays can be insconsistent. Recently, four canine retrotransposon mobile element insertions (MEIs) in or near genes WBSCR17 (Cfa6.6 and Cfa6.7), GTF2I (Cfa6.66) and POM121 (Cfa6.83) were identified in domestic dogs and gray wolves. Variations in these MEIs were significantly associated with a heightened propensity to initiate prolonged social contact or hypersociability. Using our dataset of 837 dogs, 228 of which had paired survey-based behavioral data, we discovered that one of the insertions in WBSCR17 is the most important predictor of dog sociable behaviors related to human proximity, measured by the Canine Behavioral Assessment Research Questionnaire (C-BARQ©). We found a positive correlation between insertions at Cfa6.6 and dog separation distress in the form of restlessness when about to be left alone by the owner. Lastly, assistance dogs showed significant heterozygosity deficiency at locus Cfa6.6 and higher frequency of insertions at Cfa6.6 and Cfa6.7. We suggest that training programs could utilize this genetic survey to screen for MEIs at WBSCR17 to identify dogs with sociable traits compatible with successful assistance dog performance.