Impact of Training Discipline and Experience on Inhibitory Control and Cognitive Performance in Pet Dogs

Training experience has been shown to enhance a dog's cognitive performance when comparing highly trained working or sporting dogs with untrained dogs. However, whether the type or level of training a pet dog receives can alter their performance in cognitive tasks requiring inhibitory control has not been assessed. Here, we tested whether pet dogs trained in scent work, agility, and obedience differ in cognitive performance. The impact of primary training discipline and combined training experience was assessed using two well-defined tasks that require inhibitory control: (1) the A-not-B task, in which dogs must inhibit a previously learned response in favour of an alternative response; and (2) the detour task, in which dogs must inhibit a direct approach to food to gain a reward. Dogs trained in scent work demonstrated higher levels of inhibitory control and persistence across the two tasks, but this did not affect individual task performance. Increased combined training experience improved learning in the A-not-B task training phase, but did not alter performance during the test phase, whereas it had no effect on success in the detour task. Overall, dogs that performed better in the A-not-B task were also more likely to succeed in the detour task, showing a relationship in the cognitive ability underpinning performance in the two tasks. The effect of the primary discipline on the behavioural phenotype shows that this should be accounted for in future studies, rather than applying the practice of partitioning dogs into highly trained vs. untrained groups.

Still-face effect in domestic dogs: comparing untrained with trained and animal assisted interventions dogs

The still-face effect has been extensively studied in human infants and comprises the reduction in affiliative behaviors and increased stress that occurs after a sudden interruption of social interaction with a caregiver. Domestic dogs (Canis familiaris) are model candidates for showing this effect, as they form deep bonds with their owners and interspecific social interaction is reinforcing to them. The aim of these studies was to assess if companion dogs exhibit the still-face effect and whether prior experiences during ontogeny modulate this effect. To this end, Study 1 compared dogs with different levels of training (untrained, intermediate, and advanced), while Study 2 assessed dogs that participated in Animal Assisted Interventions (AAIs) and companion dogs (CDs). The procedure was carried out virtually and comprised three phases lasting 1 min: interaction, still-face (the owner turned suddenly indifferent), and reunion (the interaction was resumed). Dogs exhibited a decrease in proximity to and contact with the owner, as well as an increase in begging and stress behaviors during the still-face phase. Moreover, this was not observed in a control condition in which the interaction continued in the same way during all three phases, discarding alternative explanations for these changes. These results show that dogs experience a still-face effect in a similar way to infants, highlighting the value interspecific social interaction has for dogs. Nevertheless, the absence of differences according to their training level or participation in AAIs suggests this is a robust phenomenon, which appears to be less susceptible to the influences of ontogenetic experiences.

Are domesticated animals dumber than their wild relatives? A comprehensive review on the domestication effects on animal cognitive performance

Animal domestication leads to diverse behavioral, physiological, and neurocognitive changes in domesticated species compared to their wild relatives. However, the widely held belief that domesticated species are inherently less "intelligent" (i.e., have lower cognitive performance) than their wild counterparts requires further investigation. To investigate potential cognitive disparities, we undertook a thorough review of 88 studies comparing the cognitive performance of domesticated and wild animals. Approximately 30% of these studies showed superior cognitive abilities in wild animals, while another 30% highlighted superior cognitive abilities in domesticated animals. The remaining 40% of studies found similar cognitive performance between the two groups. Therefore, the question regarding the presumed intelligence of wild animals and the diminished cognitive ability of domesticated animals remains unresolved. We discuss important factors/limitations for interpreting past and future research, including environmental influences, diverse objectives of domestication (such as breed development), developmental windows, and methodological issues impacting cognitive comparisons. Rather than perceiving these limitations as constraints, future researchers should embrace them as opportunities to expand our understanding of the complex relationship between domestication and animal cognition.

Dogs outperform cats both in their testability and relying on human pointing gestures: a comparative study

The dog is a so far unique species to study interspecific communication and a promising evolutionary model for preverbal human communication. Recently cats were reported to show some similar skills to dogs. Here we directly compared both the testability and the success of companion dogs and cats in relying on human distal pointing gestures. Due to differences in their domestication, social and ecological background, and developmental processes, we expected better performance from dogs compared to cats. Using an object-choice task, cats made considerably fewer choices than dogs in the laboratory environment, and their tendency to make a choice declined during trials. They were slightly more testable at home, where their willingness to choose did not decrease over time. Dogs made more successful choices than cats, both at the group and individual level, irrespective of the type of the pointing gesture. Older cats were more successful. Despite the two species' rather similar role nowadays as human companions, our results support previous findings suggesting that, compared to the dog, the cat is a less ideal model to study some human communicative abilities in a laboratory environment.

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.

Pet dogs (Canis familiaris) re-engage humans after joint activity

Joint intentionality, the mutual understanding of shared goals or actions to partake in a common task, is considered an essential building block of theory of mind in humans. Domesticated dogs are unusually adept at comprehending human social cues and cooperating with humans, making it possible that they possess behavioral signatures of joint intentionality in interactions with humans. Horschler and colleagues (Anim Behav 183: 159-168, 2022) examined joint intentionality in a service dog population, finding that upon interruption of a joint experience, dogs preferentially re-engaged their former partner over a passive bystander, a behavior argued to be a signature of joint intentionality in human children. In the current study, we aimed to replicate and extend these results in pet dogs. One familiar person played with the dog and then abruptly stopped. We examined if dogs would preferentially re-engage the player instead of a familiar bystander who was also present. Consistent with the findings of Horschler and colleagues (Anim Behav 183: 159-168, 2022), pet dogs preferentially gazed toward and offered the toy to the player significantly more than the familiar bystander. However, no difference was observed in physical contact. These findings provide preliminary evidence for behavioral signatures of joint intentionality in pet dogs, but future work is needed to understand whether this phenomenon extends to other contexts.

The Begging Strategy of Andean Dogs: An Exploratory Study

In this study, we report a particular begging strategy by Andean dogs and by humans on the unsurfaced road between the villages of Parotani and Cahiuasi in Bolivia. The positions of the dogs and humans begging and their behavioral displays were recorded. In dogs, the distance from each other was also recorded. Begging locations, for both dogs and humans, were permuted with a score, according to the higher probability of receiving food. The highest scores were assigned to the positions where cars had to slow down and the subjects were well visible, thus meriting a score corresponding to the higher probability of receiving a treat. The occurrences of the correct positioning at the external and internal parts of the bend were compared by a chi-square test. On a range of 93.3 km, the dogs were observed to always lie down at the border of the road, mainly alone (96.3%) and on hairpin bends, present due to the steep slope, obliging the vehicles to slow down. Humans were observed mainly in groups. The percentage of dogs lying on the external part of the bends was 81.2%, which was above the level of chance (p < 0.01). Humans were observed at external bends in 63.6% of cases, which was at chance level. Begging locations, for both dogs and humans, were permuted with a score according to the higher probability of receiving food. The mean scores were 1.48 and 0.65 for dogs and humans, respectively, and the difference was highly significant (p < 0.001).

Unwilling or unable? Using three-dimensional tracking to evaluate dogs' reactions to differing human intentions

The extent to which dogs (Canis familiaris) as a domesticated species understand human intentions is still a matter of debate. The unwilling-unable paradigm has been developed to examine whether nonhuman animals are sensitive to intentions underlying human actions. In this paradigm, subjects tended to wait longer in the testing area when presented with a human that appeared willing but unable to transfer food to them compared to an unwilling (teasing) human. In the present study, we conducted the unwilling-unable paradigm with dogs using a detailed behavioural analysis based on machine-learning driven three-dimensional tracking. Throughout two preregistered experiments, we found evidence, in line with our prediction, that dogs reacted more impatiently to actions signalling unwillingness to transfer food rather than inability. These differences were consistent through two different samples of pet dogs (total n = 96) and they were evident also in the machine-learning generated three-dimensional tracking data. Our results therefore provide robust evidence that dogs distinguish between similar actions (leading to the same outcome) associated with different intentions. However, their reactions did not lead to any measurable preference for one experimenter over the other in a subsequent transfer phase. We discuss different cognitive mechanisms that might underlie dogs' performance in this paradigm.

Canine perspective-taking

An important question in the study of canine cognition is how dogs understand humans, given that they show impressive abilities for interacting and communicating with us. In this review, we describe and discuss studies that have investigated dogs' perspective-taking abilities. There is solid evidence that dogs are not only sensitive to the gaze of others, but also their attention. We specifically address the question whether dogs have the ability to take the perspective of others and thus come to understand what others can or cannot perceive. From the latter, they may then infer what others know and use this representation to anticipate what others do next. Still, dogs might simply rely on directly observable cues and on what they themselves can perceive when they assess what others can perceive. And instead of making inferences from representations of others' mental states, they may have just learned that certain behaviours of ours lead to certain outcomes. However, recent research seems to challenge this low-level explanation. Dogs have solved several perspective-taking tasks instantly and reliably across a large number of variations, including geometrical gaze-following, stealing in the dark, concealing information from others, and Guesser/Knower differentiation. In the latter studies, dogs' choices between two human informants were strongly influenced by cues related to the humans' visual access to the food, even when the two informants behaved identically. And finally, we review a recent study that found dogs reacting differently to misleading suggestions of human informants that have either a true or false belief about the location of food. We discuss this surprising result in terms of the comprehension of reality-incongruent mental states, which is considered as a hallmark of Theory of Mind acquisition in human development. Especially on the basis of the latter findings, we conclude that pet dogs might be sensitive to what others see, know, intend, and believe. Therefore, this ability seems to have evolved not just in the corvid and primate lineages, but also in dogs.

Eye-tracking as a window into primate social cognition

Over the past decade, noninvasive, restraint-free eye-tracking research with primates has transformed our understanding of primate social cognition. The use of this technology with many primate species allows for the exploration and comparison of how these species attend to and understand social agents and interactions. The ability to compare and contrast the cognitive capacities of various primate species, including humans, provides insight into the evolutionary mechanisms and selective pressures that have likely shaped social cognition in similar and divergent ways across the primate order. In this review, we begin by discussing noninvasive behavioral methods used to measure primate gaze and attention before the introduction of noninvasive, restraint-free eye-tracking methodologies. Next, we focus on findings from recent eye-tracking research on primate social cognition, beginning with simple visual and search mechanisms. We then discuss the results that have built on this basic understanding of how primates view images and videos, exploring discrimination and knowledge of social agents, following social cues, tracking perspectives and predicting behavior, and the combination of eye-tracking and other behavioral and physiological methods. Finally, we discuss some future directions of noninvasive eye-tracking research on primate social cognition and current eye-tracking work-in-progress that builds on these previous studies, investigating underexplored socio-cognitive capacities and utilizing new methodologies.

Evaluating ADHD Assessment for Dogs: A Replication Study

The family dog, in its natural environment, exhibits neuropsychological deficits redolent of human psychiatric disorders, including behaviours similar to human Attention-Deficit/Hyperactivity Disorder (ADHD) symptoms. For dogs, Vas and colleagues developed a 13-item questionnaire to measure inattention and hyperactivity/impulsivity (Dog ARS; 2007). We re-assessed, in a large sample of dogs (N = 319), psychometric properties of the Dog ARS, to identify possible limitations as a basis for further development. We examined the cross-study stability of factor structure and 40-day temporal stability of item and subscale scores and compared owner-report with expert (dog trainer)-report (n = 86), paralleling human parent/teacher assessments. To identify ambiguous items, we administered a modified version (including “I don’t know” options, N = 520) to a different sample. We could replicate the factor structure with evidence of good internal consistency and test–retest reliability of both subscales. Agreement between owner and trainer ratings was fair (inattention) and moderate (hyperactivity/impulsivity). Three ambiguous items were identified. Overall, we claim that the Dog ARS is a reliable tool to assess ADHD-like behaviour in dogs, but in its current form, it is not suitable to detect diagnosable individuals, as it does not comprise items assessing functional impairment, and also, the inclusion of owner-expert ratings in the evaluation process would be necessary.

Development of Desirable Behaviors in Dog-Assisted Interventions

Simple Summary

In a recent paper, Hall et al. encouraged professionals of canine training to share their observations and procedures with researchers in the field of dog learning and cognition, with the goal of coordinating knowledge and make better use of time and resources. In response to this invitation, here, we present an integrative method for the training of dogs that take part in animal-assisted interventions (AAI). This method has been developed taking into account the needs observed during nearly 30 years of interventions for the cognitive, relational, functional, and emotional improvement of the users. This method focuses on the dog, developing in the animals the necessary skills for their inclusion in dog-assisted interventions from a constructivist perspective, while guaranteeing their well-being during the training and the execution of their tasks.

Abstract

Dog-assisted interventions (DAI) are those that include specially trained dogs in human health services. Often, the training methods employed to train animals for DAI are transmitted between trainers, so the latest scientific research on dog learning and cognition is not always taken into account. The present work aims to evaluate the impact that the main theories on the evolution of the dog have had both in promoting different training methods and in the relevance of behavior in the evolution of the skills of actual dogs. Then, an integrative method for the training of dogs is presented. This method takes into account the research on dog learning mechanisms and cognition processes, and effectively promotes the development of desirable behaviors for DAI during the dog’s ontogeny.

Social Stimulation by the Owner Increases Dogs’ (Canis familiaris) Social Susceptibility in a Food Choice Task—The Possible Effect of Endogenous Oxytocin Release

Recent evidence suggests a human-like susceptibility to social influence in dogs. For example, dogs tend to ignore their ‘natural’ preference for the larger amount of food after having seen a human’s explicit preference for a smaller quantity. However, it is still unclear whether this tendency to conform to the partner’s behaviour can be influenced by social stimuli and/or the neurohormone oxytocin as primers to prosocial predispositions. In Experiment I, eighty two dogs were tested using Prato-Previde et al.’s food quantity preference task. In Experiment I, we investigated in a 2 × 2 design how (i) a 10-minute-long social stimulation by the owner versus a socially ignoring pre-treatment as well as (ii) on-line ostensive communications versus no communication during task demonstration affect dogs’ (N = 82) choices in the abovementioned food choice task. Results indicate that the owners’ pre-treatment with social stimuli (eye contact, petting) increased dogs’ susceptibility to the experimenter’s food preference, but the salient ostensive addressing signals accompanying human demonstration masked this social priming effect. In Experiment II, N = 32 dogs from the subjects of Experiment I were retested after oxytocin (OT) or placebo (PL) pre-treatments. This experiment aimed to study whether intranasal administration of oxytocin as compared to placebo treatment would similarly increase dogs’ tendency to re-enact the human demonstrator’s counterproductive choice in the same task. Results showed an increased susceptibility to the human preference in the OT group, suggesting that both socially stimulating pre-treatment and the intranasal administration of oxytocin have similar priming effects on dogs’ social susceptibility.

Did Dog Domestication Contribute to Language Evolution?

Different factors seemingly account for the emergence of present-day languages in our species. Human self-domestication has been recently invoked as one important force favoring language complexity mostly via a cultural mechanism. Because our self-domestication ultimately resulted from selection for less aggressive behavior and increased prosocial behavior, any evolutionary or cultural change impacting on aggression levels is expected to have fostered this process. Here, we hypothesize about a parallel domestication of humans and dogs, and more specifically, about a positive effect of our interaction with dogs on human self-domestication, and ultimately, on aspects of language evolution, through the mechanisms involved in the control of aggression. We review evidence of diverse sort (ethological mostly, but also archeological, genetic, and physiological) supporting such an effect and propose some ways of testing our hypothesis.

The Research of Standardized Protocols for Dog Involvement in Animal-Assisted Therapy: A Systematic Review

Dogs are considered the most important species involved in animal-assisted therapy (AAT), and the scientific literature focuses on the benefits linked to the involvement of dogs in various therapeutic areas. In this study, we carried out a systematic review according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, exploring the scientific literature from the last 5 years (2016-2021) on three databases (PubMed, Scopus, and Web of Science) to highlight the characteristics of the dogs involved in AATs. Based on the scientific literature relevant to such dogs, we considered different parameters (i.e., number, age, sex, breed, temperament, methods of choice and training, health status, research goals, and activities with dogs) to include studies in our paper. After screening 4331 papers identified on the searched databases, we selected 38 articles that met the inclusion criteria. Analysis of the included articles showed that the characteristics of the dogs were neglected. Our findings indicated a lack of information about the dogs, as well as the absence of standardized and univocal criteria for dog selection, training programs, and health protocols.

Dogs follow human misleading suggestions more often when the informant has a false belief

We investigated whether dogs (Canis familiaris) distinguish between human true (TB) and false beliefs (FB). In three experiments with a pre-registered change of location task, dogs (n = 260) could retrieve food from one of two opaque buckets after witnessing a misleading suggestion by a human informant (the 'communicator') who held either a TB or a FB about the location of food. Dogs in both the TB and FB group witnessed the initial hiding of food, its subsequent displacement by a second experimenter, and finally, the misleading suggestion to the empty bucket by the communicator. On average, dogs chose the suggested container significantly more often in the FB group than in the TB group and hence were sensitive to the experimental manipulation. Terriers were the only group of breeds that behaved like human infants and apes tested in previous studies with a similar paradigm, by following the communicator's suggestion more often in the TB than in the FB group. We discuss the results in terms of processing of goals and beliefs. Overall, we provide evidence that pet dogs distinguish between TB and FB scenarios, suggesting that the mechanisms underlying sensitivity to others' beliefs have not evolved uniquely in the primate lineage.

Cooperative Communication with Humans Evolved to Emerge Early in Domestic Dogs

Although we know that dogs evolved from wolves, it remains unclear how domestication affected dog cognition. One hypothesis suggests dog domestication altered social maturation by a process of selecting for an attraction to humans.^1-3 Under this account, dogs became more flexible in using inherited skills to cooperatively communicate with a new social partner that was previously feared and expressed these unusual social skills early in development.^4-6 Here, we comparedog (n = 44) and wolf (n = 37) puppies, 5-18 weeks old, on a battery of temperament and cognition tasks. We find that dog puppies are more attracted to humans, read human gestures more skillfully, and make more eye contact with humans than wolf puppies. The two species are similarly attracted to familiar objects and perform similarly on non-social measures of memory and inhibitory control. These results are consistent with the idea that domestication enhanced the cooperative-communicative abilities of dogs as selection for attraction to humans altered social maturation.

Early-emerging and highly heritable sensitivity to human communication in dogs

Human cognition is believed to be unique in part because of early-emerging social skills for cooperative communication.¹ Comparative studies show that at 2.5 years old, children reason about the physical world similarly to other great apes, yet already possess cognitive skills for cooperative communication far exceeding those in our closest primate relatives.^2,3 A growing body of research indicates that domestic dogs exhibit functional similarities to human children in their sensitivity to cooperative-communicative acts. From early in development, dogs flexibly respond to diverse forms of cooperative gestures.^4,5 Like human children, dogs are sensitive to ostensive signals marking gestures as communicative, as well as contextual factors needed for inferences about these communicative acts.^6-8 However, key questions about potential biological bases for these abilities remain untested. To investigate their developmental and genetic origins, we tested 375 8-week-old dog puppies on a battery of social-cognitive measures. We hypothesized that if dogs' skills for cooperating with humans are biologically prepared, then they should emerge robustly in early development, not require extensive socialization or learning, and exhibit heritable variation. Puppies were highly skillful at using diverse human gestures, and we found no evidence that their performance required learning. Critically, over 40% of the variation in dogs' point-following abilities and attention to human faces was attributable to genetic factors. Our results suggest that these social skills in dogs emerge early in development and are under strong genetic control.

Is cognition the secret to working dog success?

Dogs' special relationship with humans not only makes them ubiquitous in our lives, but working dogs specifically perform essential functions for us such as sniffing out bombs and pulling wheelchairs for the disabled. To enhance the performance of working dogs, it is essential to understand the cognitive skills that underlie and lead to their success. This review details recent work in the field of canine cognition, including how dogs have evolved socio-cognitive skills that mimic or, in some cases, rival even our closest primate relatives. We review how these findings have laid the foundation for new studies that hope to help enhance working dog programs. This includes work that has begun to reveal the development and stability of the most important traits for service work. Discoveries like these suggest the possibility of translating what we have learned to improve breeding, selection, and training for these jobs. The latest research we review here shows promise in contributing to the production of better dogs and, consequently, more help for people.

What's the point? Domestic dogs' sensitivity to the accuracy of human informants

Dogs excel at understanding human social-communicative gestures like points and can distinguish between human informants who vary in characteristics such as knowledge or familiarity. This study explores if dogs, like human children, can use human social informants' past accuracy when deciding whom to trust. Experiment 1 tested whether dogs would behave differently in the presence of an accurate (vs. inaccurate) informant. Dogs followed an accurate informant's point significantly above chance. Further, when presented with an inaccurate point, dogs were more likely to ignore it and choose the correct location. Experiment 2 tested whether dogs could use informant past accuracy to selectively follow the point of the previously accurate informant. In test trials when informants simultaneously pointed at different locations (only one of which contained a treat), dogs chose the accurate informant at chance levels. Experiment 3 controlled for non-social task demands (e.g. understanding of hidden baiting and occlusion events) that may have influenced Experiment 2 performance. In test trials, dogs chose to follow the accurate (vs. inaccurate) informant. This suggests that like children, dogs may be able to use informants' past accuracy when choosing between information sources.

Rapid learning of object names in dogs

Learning object names after few exposures, is thought to be a typically human capacity. Previous accounts of similar skills in dogs did not include control testing procedures, leaving unanswered the question whether this ability is uniquely human. To investigate the presence of the capacity to rapidly learn words in dogs, we tested object-name learning after four exposures in two dogs with knowledge of multiple toy-names. The dogs were exposed to new object-names either while playing with the objects with the owner who named those in a social context or during an exclusion-based task similar to those used in previous studies. The dogs were then tested on the learning outcome of the new object-names. Both dogs succeeded after exposure in the social context but not after exposure to the exclusion-based task. Their memory of the object-names lasted for at least two minutes and tended to decay after retention intervals of 10 min and 1 h. This reveals that rapid object-name learning is possible for a non-human species (dogs), although memory consolidation may require more exposures. We suggest that rapid learning presupposes learning in a social context. To investigate whether rapid learning of object names in a social context is restricted to dogs that have already shown the ability to learn multiple object-names, we used the same procedure with 20 typical family dogs. These dogs did not demonstrate any evidence of learning the object names. This suggests that only a few subjects show this ability. Future studies should investigate whether this outstanding capacity stems from the exceptional talent of some individuals or whether it emerges from previous experience with object name learning.

How Dogs Perceive Humans and How Humans Should Treat Their Pet Dogs: Linking Cognition With Ethics

Humans interact with animals in numerous ways and on numerous levels. We are indeed living in an “animal”s world,’ in the sense that our lives are very much intertwined with the lives of animals. This also means that animals, like those dogs we commonly refer to as our pets, are living in a “human’s world” in the sense that it is us, not them, who, to a large degree, define and manage the interactions we have with them. In this sense, the human-animal relationship is nothing we should romanticize: it comes with clear power relations and thus with a set of responsibilities on the side of those who exercise this power. This holds, despite the fact that we like to think about our dogs as human’s best friend. Dogs have been part of human societies for longer than any other domestic species. Like no other species they exemplify the role of companion animals. Relationships with pet dogs are both very widespread and very intense, often leading to strong attachments between owners or caregivers and animals and to a treatment of these dogs as family members or even children. But how does this relationship look from the dogs’ perspective? How do they perceive the humans they engage with? What responsibilities and duties arise from the kind of mutual understanding, attachment, and the supposedly “special” bonds we form with them? Are there ethical implications, maybe even ethical implications beyond animal welfare? The past decades have seen an upsurge of research from comparative cognition on pet dogs’ cognitive and social skills, especially in comparison with and reference to humans. We will therefore set our discussion about the nature and ethical dimensions of the human–dog relationship against the background of the current empirical knowledge on dog (social) cognition. This allows us to analyze the human–dog relationship by applying an interdisciplinary approach that starts from the perspective of the dog to ultimately inform the perspective of humans. It is our aim to thereby identify ethical dimensions of the human–dog relationship that have been overlooked so far.

Does stress run through the leash? An examination of stress transmission between owners and dogs during a walk

Humans and dogs have co-evolved for over 10,000 years. Recent research suggests that, through the domestication process, dogs have become proficient at responding to human commands, attention and emotional states. However, the extent to which a companion dog responds to human emotions, such as stress, remains to be understood. This study examines whether a companion dog's stress, as measured by cortisol levels and heart rate, increases during a familiar outdoor walk in response to its owner's experience of stress. Sixty-eight owner/dog dyads participated in this study. The dyads were randomly assigned to an Experimental or Control group. Owners in the Experimental group were informed the walk would be digitally recorded for subsequent evaluation of their handling skills, whereas those in the Control group were informed the walk would be digitally recorded for archival purposes (no evaluation). This manipulation was implemented to induce a mild stress response in the owners. Salivary cortisol samples were collected from the owner and their dog before and after the walk. The dyad was also fitted with monitoring devices to record heart rate throughout the walk. Finally, personality information regarding the owner and their dog was collected. We found that cortisol production within the dyad showed a marginal inverse correlation. We also found that owners' Openness to Experience and dogs' Fearfulness influenced the heart rate of the other during the first minute of a walk. These results support that although stress may be detected within a dyad, this does not result in an associated significant change in cortisol or heart rate.

Human-dog relationships as a working framework for exploring human-robot attachment: a multidisciplinary review

Robotic agents will be life-long companions of humans in the foreseeable future. To achieve such successful relationships, people will likely attribute emotions and personality, assign social competencies, and develop a long-lasting attachment to robots. However, without a clear theoretical framework-building on biological, psychological, and technological knowledge-current societal demands for establishing successful human-robot attachment (HRA) as a new form of inter-species interactions might fail. The study of evolutionarily adaptive animal behavior (i.e., ethology) suggests that human-animal behaviors can be considered as a plausible solution in designing and building models of ethorobots-including modeling the inter-species bond between domesticated animals and humans. Evidence shows that people assign emotional feelings and personality characteristics to animal species leading to cooperation and communication-crucial for designing social robots such as companion robots. Because dogs have excellent social skills with humans, current research applies human-dog relationships as a template to understand HRA. Our goal of this article is twofold. First, we overview the research on how human-dog interactions are implemented as prototypes of non-human social companions in HRA. Second, we review research about attitudes that humans have for interacting with robotic dogs based on their appearance and behavior, the implications for forming attachments, and human-animal interactions in the rising sphere of robot-assisted therapy. The rationale for this review is to provide a new perspective to facilitate future research among biologists, psychologists, and engineers-contributing to the creation of innovative research practices for studying social behaviors and its implications for society addressing HRA.

The scholar's best friend: research trends in dog cognitive and behavioral studies

In recent decades, cognitive and behavioral knowledge in dogs seems to have developed considerably, as deduced from the published peer-reviewed articles. However, to date, the worldwide trend of scientific research on dog cognition and behavior has never been explored using a bibliometric approach, while the evaluation of scientific research has increasingly become important in recent years. In this review, we compared the publication trend of the articles in the last 34 years on dogs’ cognitive and behavioral science with those in the general category “Behavioral Science”. We found that, after 2005, there has been a sharp increase in scientific publications on dogs. Therefore, the year 2005 has been used as “starting point” to perform an in-depth bibliometric analysis of the scientific activity in dog cognitive and behavioral studies. The period between 2006 and 2018 is taken as the study period, and a backward analysis was also carried out. The data analysis was performed using “bibliometrix”, a new R-tool used for comprehensive science mapping analysis. We analyzed all information related to sources, countries, affiliations, co-occurrence network, thematic maps, collaboration network, and world map. The results scientifically support the common perception that dogs are attracting the interest of scholars much more now than before and more than the general trend in cognitive and behavioral studies. Both, the changes in research themes and new research themes, contributed to the increase in the scientific production on the cognitive and behavioral aspects of dogs. Our investigation may benefit the researchers interested in the field of cognitive and behavioral science in dogs, thus favoring future research work and promoting interdisciplinary collaborations.

The link between selection for function and human-directed play behaviour in dogs

Human-directed play behaviour is a distinct behavioural feature of domestic dogs. But the role that artificial selection for contemporary dog breeds has played for human-directed play behaviour remains elusive. Here, we investigate how human-directed play behaviour has evolved in relation to the selection for different functions, considering processes of shared ancestry and gene flow among the different breeds. We use the American Kennel Club (AKC) breed group categorization to reflect the major functional differences and combine this with observational data on human-directed play behaviour for over 132 breeds across 89 352 individuals from the Swedish Dog Mentality Assessment project. Our analyses demonstrate that ancestor dogs already showed intermediate levels of human-directed play behaviour, levels that are shared with several modern breed types. Herding and Sporting breeds display higher levels of human-directed play behaviour, statistically distinguishable from Non-sporting and Toy breeds. Our results suggest that human-directed play behaviour played a role in the early domestication of dogs and that subsequent artificial selection for function has been important for contemporary variation in a behavioural phenotype mediating the social bond with humans.

Showing behavior in Animal Assisted Intervention and pet dogs

A dog's behavior can indicate the location of hidden food to a human who is unaware of its position. These behavioral patterns are known as showing behavior, which comprise gazing towards the target location and gaze alternation between the human and the target (i.e., hidden food). Although this ability has been extensively studied in pet dogs, research has not yet focused on dogs with other kinds of life experiences, such as dogs working in Animal Assisted Interventions (AAI). These dogs are exposed to novel environments under the guidance of their handlers and previous studies have highlighted the importance of gazing behavior in this population. Therefore, we evaluated AAI and pet dogs on a showing task. Results indicate that dogs overall engaged in showing behavior as they gazed more towards the baited pot and alternated their gaze more on showing trials than control ones. Contrary to our expectations, differences between AAI and pet dogs were minimal. However, owners of AAI dogs were more successful than owners of pet dogs in finding the hidden food in showing trials. This suggests they may be more skillful in reading their dogs' behavior, which can be crucial to ensure their welfare during AAI sessions.

Selective overimitation in dogs

Dogs have not only shown different kinds of social learning, from either conspecifics or humans, including do-as-I-do imitation, deferred imitation, and selective imitation, but in two previous studies they have also shown an eagerness to copy causally irrelevant actions. This so-called overimitation is prevalent in humans but is totally absent in great apes. Whereas in one of two previous studies dogs copied actions from an experimenter (Johnston, Holden, & Santos in Developmental Science, 20, e12460, 2017), in the other a reasonable number of the dogs copied the irrelevant actions from their human caregiver (Huber, Popovová, Riener, Salobir, & Cimarelli in Learning & Behavior, 46, 387-397, 2018). Dogs have not only been domesticated to live and work with us, but many companion dogs develop strong affiliative relationships with their caregiver, which are akin to the attachment bonds between human children and their mother. We therefore assumed that overimitation in dogs might be strongly motivated by social factors, such as affiliation or conformity. To test this hypothesis, we confronted dogs with the same demonstration of causally relevant and irrelevant actions as in the previous study (Huber et al. in Learning & Behavior, 46, 387-397, 2018), but this time with an unfamiliar experimenter instead of the caregiver as the demonstrator. The results strongly supported our hypothesis: Whereas half of the subjects in the previous study replicated the causally irrelevant action demonstrated by their caregiver, only very few did so when the actions were demonstrated by the experimenter. We conclude that the eagerness of dogs to learn from humans and to copy even unnecessary actions is strongly facilitated by their relationship with the particular human.

Behavioral and Neurophysiological Correlates of Dogs' Individual Sensitivities to Being Observed by Their Owners While Performing a Repetitive Fetching Task

Ample evidence suggests that dogs possess enhanced skills in reading human visual attention, but it remains to be explored whether they are sensitive to the audience effect in their interactions with humans. The present study aimed to investigate how dogs’ behavior is affected by their owners’ visual attention while performing a repetitive task (bringing an object back to an unfamiliar experimenter while the owner waited passively). We assumed that if dogs are susceptible to the audience effect, their task persistence and task performance would vary according to their owners’ attentiveness. A group of adult pet dogs (N = 27) were repeatedly presented with an object retrieval task by the experimenter (N = 20 trials) while owners either ignored their dogs (Inattentive Owner condition) or paid attention to their dogs’ actions (Attentive Owner condition). Behavioral observations were complemented with the owner’s reports of their relationships with their dogs (assessed by means of an owner–pet attachment questionnaire) and dogs’ spectral EEG sleep profile (recorded during 3-h-long daytime sleep). Although dogs, independently of their owners’ attentional state, were generally willing to comply with the fetching task, they were faster to approach the toy object and gazed significantly longer at their owners when he/she was paying attention. This finding is reminiscent of peer influence observed in humans. Further, characteristics of relationship insecurity (relationship anxiety and avoidance) were associated with dogs’ task persistence and performance. Dogs of owners with higher relationship anxiety tended to approach the toy object less frequently, and dogs of owners with higher relationship avoidance and anxiety were more hesitant to approach the toy object. We also found that dogs’ individual susceptibilities to the audience effect is related to EEG spectral power of both REM and non-REM sleep as well as in pre-sleep (drowsiness) in a trait-like manner. These results, in line with previous findings, support the notion that dogs have a somewhat human-like susceptibility to the audience effect, a trait which might be linked to more complex mechanisms, such as self-presentation or reputation management, helping the two species to become effective social partners.

Effect of shared information and owner behavior on showing in dogs (Canis familiaris)

Dogs’ production of referential communicative signals, i.e., showing, has gained increasing scientific interest over the last years. In this paper, we investigate whether shared information about the present and the past affects success and form of dog–human interactions. Second, in the context of showing, owners have always been treated as passive receivers of the dog’s signals. Therefore, we examined whether the owner’s behavior can influence the success and form of their dog’s showing behavior. To address these questions, we employed a hidden-object task with knowledgeable dogs and naïve owners. Shared information about the present was varied via the spatial set-up, i.e., position of hiding places, within dog–owner pairs, with two conditions requiring either high or low precision in indicating the target location. Order of conditions varied between pairs, representing differences in shared knowledge about the past (communication history). Results do not support an effect of communication history on either success or showing effort. In contrast, the spatial set-up was found to affect success and choice of showing strategies. However, dogs did not adjust their showing effort according to different spatial set-ups. Our results suggest that the latter could be due to the owner’s influence. Owner behavior generally increased the effort of their dog’s showing behavior which was stronger in the set-up requiring low showing precision. Moreover, our results suggest that owners could influence their dog’s showing accuracy (and thereby success) which, however, tended to be obstructive.

The evolutionary origins of natural pedagogy: Rhesus monkeys show sustained attention following nonsocial cues versus social communicative signals

The natural pedagogy hypothesis proposes that human infants preferentially attend to communicative signals from others, facilitating rapid cultural learning. In this view, sensitivity to such signals is a uniquely human adaptation and as such nonhuman animals should not produce or utilize these communicative signals. We test these evolutionary predictions by examining sensitivity to communicative cues in 206 rhesus monkeys (Macaca mulatta) using an expectancy looking time task modeled on prior work with infants. Monkeys observed a human actor who either made eye contact and vocalized to the monkey (social cue), or waved a fruit in front of her face and produced a tapping sound (nonsocial cue). The actor then either looked at an object (referential look) or looked toward empty space (look away). We found that, unlike human infants in analogous situations, rhesus monkeys looked longer at events following nonsocial cues, regardless of the demonstrator's subsequent looking behavior. Moreover younger and older monkeys showed similar patterns of responses across development. These results provide support for the natural pedagogy hypothesis, while also highlighting evolutionary changes in human sensitivity to communicative signals.

Multimodal signaling in the visuo-acoustic mismatch paradigm: similarities between dogs and children in the communicative approach

In this review, we have analyzed the studies on the "mismatch paradigm" or "contrasting paradigm", in which the word indicates an intent that is opposite to the gesture in dogs and children. The studies on children highlighted the importance of the type of gestural messages that, when delivered in a non-ostensive manner, assume less value than the verbal indication; whereas, when more emphasis is given to the gestures, it produces opposite results. Word-trained dogs appear to rely more on words, but in the absence of such specific training, dogs rely more on gestures either in transitive or intransitive actions. Moreover, gestural communication appears easier to generalize, since dogs respond equally well to the gestural messages of familiar persons and strangers, whereas their performance lowers when a stranger provides a vocal message. Visual signals trigger faster responses than auditory signals, whereas verbal indications can at most equal the gestural latencies, but never overcome them. Female dogs appeared to be more proficient in the interpretation of gestural commands, while males performed better in the case of verbal commands. Based on a PRISMA analyses from the Web of Science database, three papers on children and four on dogs were retrieved. Our analyses revealed that gestures are more reliable reference points than words for dogs and children. Future studies should focus on choices related to objects of different values for the subjects. Moreover, the choices of dogs should be compared using known and unknown objects, which might help clarify how familiarity with the objects could differently influence their responses.

The development of problem-solving abilities in a population of candidate detection dogs (Canis familiaris)

Both ontogenetic and phylogenetic factors have shaped dogs' cognitive capabilities, resulting in a heightened social sensitivity at the apparent cost of non-social problem-solving abilities. Research has suggested that training history and life experience can influence problem-solving abilities in dogs. However, the ontogenetic development of problem-solving abilities in dogs has been less explored. We tested a population of candidate detection dogs of various ages across the first year of development on four well-established problem-solving tasks targeting different cognitive domains (i.e., cylinder, A-not-B barrier, delayed search, and spatial transposition tasks). We examined developmental effects by comparing cognitive task performance across three age groups. Age-related improvements for all four cognitive measures indicate developmental increases in processes related to inhibitory control, attention, and spatial cognition between 3 and 12 months of age. Additionally, we found some relationships between cognitive measures and detection dog performance measures, though effects were not as robust. We discuss the results in the context of canine cognitive development and corresponding effects of phylogeny and ontogeny, as well as potential applications to working dog training and selection.

Long-Term Socialization with Humans Affects Human-Directed Behavior in Goats

Simple Summary

Goats are a useful model species to explore the effects of ontogenesis on the socio-cognitive abilities of domestic non-companion animals. The aim of this research was to study the behavioral response of goats with different socialization backgrounds to humans in the impossible task paradigm. Two groups of goats (high and low levels of socialization) were tested. Highly socialized goats interacted more with humans (the experimenter) during the test, while the low socialization group exhibited a higher level of interaction with the exit door.

Abstract

Throughout their evolutionary history, humans have tried to domesticate a variety of wild terrestrial mammals, resulting in a limited number that has been successfully domesticated. Among these domesticated species, domestic goats (Capra aegagrus hircus) are a useful model species to study the effects of ontogenesis on the socio-cognitive abilities of domestic non-companion animals in their interactions with humans. To this end, the behavioral responses of two groups of goats with a different background of human socialization (high and low socialization) were compared in the impossible task test, an experimental paradigm aimed to study socio-cognitive skills and the tendency to interact with humans. Our results show that, when the task became impossible to solve, goats with a higher level of socialization interacted with the experimenter for a greater amount of time than subjects in the low socialization group, whereas the latter group exhibited increased door directed behavior. Overall, highly socialized goats made more social contact with humans compared to the other group in the impossible task paradigm.

Cats show an unexpected pattern of response to human ostensive cues in a series of A-not-B error tests

It is an intriguing question whether cats' social understanding capacity, including the sensitivity to ostensive signals (resulting in fast preferential learning of behavioural choices demonstrated by humans), would be comparable to that in dogs. In a series of A-not-B error tests, we investigated whether the ostensive or non-ostensive manner of human communication and the familiarity of the human demonstrator would affect the search error pattern in companion cats. Cats' performance showed an almost completely different distribution of perseverative erring than earlier was shown in dogs and human infants. Cats demonstrated perseverative errors both during ostensive and non-ostensive cueing by the owner and also during non-ostensive cueing by the experimenter. However, unlike prior studies with dogs, they avoided perseverative errors during the experimenter ostensive cueing condition. We assume that the reliance on human ostensive signals may serve different purpose in companion dogs and cats-meanwhile in dogs, human ostension could support fast rule learning, in cats, it may have only a circumstantial attention-eliciting effect. Our results highlight the need of conducting further throughout experiments on the social cognition of cats, based on their own right beside the traditional cat-dog comparative approach.

Intrinsic Ball Retrieving in Wolf Puppies Suggests Standing Ancestral Variation for Human-Directed Play Behavior

Domestication dramatically alters phenotypes across animal species. Standing variation among ancestral populations often drives phenotypic change during domestication, but some changes are caused by novel mutations. In dogs (Canis familiaris) specifically, it has been suggested that the ability to interpret social-communicative behavior expressed by humans originated post-domestication and this behavior is thus not expected to occur in wolves (Canis lupus). Here we report the observation of three 8-week-old wolf puppies spontaneously responding to social-communicative behaviors from an unfamiliar person by retrieving a ball. This behavioral expression in wolves has significant implications for our understanding and expectations of the genetic foundations of dog behavior. Importantly, our observations indicate that behavioral responses to human social-communicative cues are not unique to dogs. This suggests that, although probably rare, standing variation in the expression of human-directed behavior in ancestral populations could have been an important target for early selective pressures exerted during dog domestication.

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Dogs, unlike wolves, are suggested to have the ability to interpret human cues

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Yet, untrained wolf puppies will spontaneously retrieve a ball based on human cues

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Standing variation for human-directed behavior in ancestral wolf populations

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Human-directed behavior important during early selection in dog domestication

Gazing as a help requesting behavior: a comparison of dogs participating in animal-assisted interventions and pet dogs

Dogs tend to gaze at humans when they are confronted with inaccessible food during an unsolvable task, which is often interpreted as a help requesting behavior. Dogs who participate in animal-assisted interventions (AAI) interact with many people during their lives and prior studies have emphasized the importance of gazing in their communication. We compared the behavior of AAI (n = 15) and pet (n = 16) dogs during an unsolvable task, using a container fixed to a wooden board with inaccessible food inside, while the owner and an unfamiliar woman stood facing each other at the sides of the board ignoring the dog. Results showed that AAI dogs spent significantly more time gazing and alternated their gaze more frequently between the container and the people than pet dogs. In addition, they spent more time in contact with the unfamiliar person. However, no significant differences were found in the time dogs of either group gazed towards the owner compared to the unfamiliar person, in the frequency of gaze alternation or in the time spent interacting with the apparatus. In line with prior studies, these results suggest that gazing may be a significant communicative response in AAI dogs, which could probably contribute to having a better coordination with their handler. A greater understanding of the characteristics of this population may aid the selection and training of AAI dogs, which is particularly relevant given the increased popularity of AAI nowadays.

Individual performance across motoric self-regulation tasks are not correlated for pet dogs

Inhibitory control, the ability to restrain a prepotent but ineffective response in a given context, is thought to be indicative of a species' cognitive abilities. This ability ranges from "basic" motoric self-regulation to more complex abilities such as self-control. During the current study, we investigated the motoric self-regulatory abilities of 30 pet dogs using four well-established cognitive tasks - the A-not-B Bucket task, the Cylinder task, the Detour task, and the A-not-B Barrier task - administered in a consistent context. One main goal of the study was to determine whether the individual-level performance would correlate across tasks, supporting that these tasks measure similar components of motoric self-regulation. Dogs in our study were quite successful during tasks requiring them to detour around transparent barriers (i.e., the Cylinder and Detour tasks), but were less successful with tasks requiring the production of a new response (i.e., A-not-B Bucket and A-not-B Barrier tasks). However, individual dog performance did not correlate across tasks, suggesting these well-established tasks likely measure different inhibitory control abilities, or are strongly influenced by differential task demands. Our results also suggest other aspects such as perseveration or properties of the apparatus may need to be carefully examined in order to better understand canine motoric self-regulation or inhibitory control more generally.

Dogs do not demonstrate a human-like bias to defer to communicative cues

Human children and domesticated dogs learn from communicative cues, such as pointing, in highly similar ways. In two experiments, we investigate whether dogs are biased to defer to these cues in the same way as human children. We tested dogs on a cueing task similar to one previously conducted in human children. Dogs received conflicting information about the location of a treat from a Guesser and a Knower, who either used communicative cues (i.e., pointing; Experiments 1 and 2), non-communicative physical cues (i.e., a wooden marker; Experiment 1), or goal-directed actions (i.e., grasping; Experiment 2). Although human children tested previously struggled to override inaccurate information provided by the Guesser when she used communicative cues, in contrast to physical cues or goal-directed actions, dogs were more likely to override the Guesser's information when she used communicative cues or goal-directed actions than when she used non-communicative physical cues. Given that dogs did not show the same selective bias towards the Guesser's information in communicative contexts, these findings provide clear evidence that dogs do not demonstrate a human-like bias to defer to communicative cues. Instead, dogs may be more likely to critically evaluate information presented via communicative cues than either physical or non-communicative cues.

Would dogs copy irrelevant actions from their human caregiver?

Companion dogs learn easily from humans, including human behavior, human communication, and some aspects of the human-made environment. They benefit from having the opportunity to learn from humans and are able to spontaneously synchronize their behavior with that of their caregiver. Here, we tested whether pet dogs would show a special form of observational learning, one that has been considered uniquely human. Indeed, humans show overimitation, the faithful copying of causally irrelevant actions, but great apes do not. Because in humans this peculiar form of imitation is strongly motivated by social factors, such as affiliation or conformity, we hypothesized that domesticated and enculturated dogs are more likely than apes are to copy such actions, especially if shown by their affiliated caregiver. Indeed, half of the dogs replicated a causally irrelevant action that was demonstrated by their caregiver, and about the same number did this whether they saw only this action being demonstrated or being demonstrated before or after a causally relevant, functional action. The demonstration of a causally relevant action, one that is immediately followed by access to food, thus does not inhibit the copying of an action that is spatially separated and functionally opaque. Given that the copying frequency in this study was low overall, these results suggest evidence for overimitation in dogs, which might challenge the human uniqueness of this type of social learning.

Physiological pathways to rapid prosocial evolution

Dogs (Canis lupus familiaris) descend from wolves (Canis lupus) sharing the same ecological niche of cooperative hunters, as humans. Initially, humans and wolves were competitors starting interspecific communication in order to avoid risk of injury. The evolutionary continuity of mammalian brains enabled interspecific prosocial contacts between both of them, which reduced stress, and enabled behavioral cultures leading to genetic isolation of those wolves. Dogs are the first domesticated animal living together with humans for about 25,000 years. Domestication means decreased aggression and flight distance toward humans, thus changes in the stress axis are crucial. The hypothesis of Active Social Domestication considers genetic selection as a necessary prediction but not a sufficient explanation of dog domestication. In addition, dog domestication is suggested to be an epigenetic disclosure. Due to changed stress activity, epigenetic mechanisms affect cerebral receptor activity and regulate transposon expressions, thus shaping brain function and behavior. Interspecific prosocial contacts initiated via serotonin release an enzymatic cascade enhancing, epigeneti-cally, the glucocorticoid negative feedback loop. Reduced chronic stress improved social learning capability and inhibitory control. Over time, those wolves could integrate themselves into human social structures, thus becoming dogs. In analogy, human mental skills, such as creating art and culture, might have also improved during the Upper Paleolithic.

Neural processes of vocal social perception: Dog-human comparative fMRI studies

In this review we focus on the exciting new opportunities in comparative neuroscience to study neural processes of vocal social perception by comparing dog and human neural activity using fMRI methods. The dog is a relatively new addition to this research area; however, it has a large potential to become a standard species in such investigations. Although there has been great interest in the emergence of human language abilities, in case of fMRI methods, most research to date focused on homologue comparisons within Primates. By belonging to a very different clade of mammalian evolution, dogs could give such research agendas a more general mammalian foundation. In addition, broadening the scope of investigations into vocal communication in general can also deepen our understanding of human vocal skills. Being selected for and living in an anthropogenic environment, research with dogs may also be informative about the way in which human non-linguistic and linguistic signals are represented in a mammalian brain without skills for language production.