The World from a Dog’s Point of View

Going back to "basics": Harlow's learning set task with wolves and dogs

To survive and reproduce, animals need to behave adaptively by adjusting their behavior to their environment, with learning facilitating some of these processes. Dogs have become a go-to model species in comparative cognition studies, making our understanding of their learning skills paramount at multiple levels, not only with regards to basic research on their cognitive skills and the effects of domestication, but also with applied purposes such as training. In order to tackle these issues, we tested similarly raised wolves and dogs in a serial learning task inspired by Harlow's "learning set." In Phase 1, different pairs of objects were presented to the animals, one of which was baited while the other was not. Both species' performance gradually improved with each new set of objects, showing that they "learnt to learn," but no differences were found between the species in their learning speed. In Phase 2, once subjects had learned the association between one of the objects and the food reward, the contingencies were reversed and the previously unrewarded object of the same pair was now rewarded. Dogs' performance in this task seemed to be better than wolves', albeit only when considering just the first session of each reversal, suggesting that the dogs might be more flexible than wolves. Further research (possibly with the aid of refined methods such as computer-based tasks) would help ascertain whether these differences between wolves and dogs are persistent across different learning tasks.

Street-wise dog testing: Feasibility and reliability of a behavioural test battery for free-ranging dogs in their natural habitat

Behavioural scientists are increasingly recognizing the need to conduct experiments in the wild to achieve a comprehensive understanding of their species' behaviour. For domestic dogs (Canis familiaris), such progress has been slow. While the life in human households is often regarded as dogs' natural habitat, this classification disregards most of the global dog population. The value of experimentally testing free-ranging dogs' cognition and behaviour is increasingly being recognized, but no comprehensive test batteries have been conducted on those populations so far, leaving the feasibility and reliability of such endeavours unknown. This study is the starting point to fill this gap by pioneering and validating an elaborate behavioural test battery on street-living dogs. Therein, six common temperament tests (human-/conspecific-directed sociability, neophobia, tractability) and dog-human communication paradigms (pointing, inaccessible object) were adapted to the street conditions. We evaluated the feasibility of the test battery, the coding reliability of the measures, and investigated their temporal consistency in a retest of the same individuals six weeks later (test-retest reliability). The test battery proved feasible with most dogs participating in all subtests, and it showed satisfactory inter- and intra-rater reliability (0.84 and 0.93 respectively), providing evidence that complex behavioural tests can be conducted even in highly variable street conditions. Retesting revealed that some behaviours could be captured reliably across time, especially when the subtest was particularly engaging (e.g., human approach, point following). In contrast, the low retest reliability for subtests relying on sustained novelty and behaviours that were highly susceptible to disturbances (e.g., gazing) reflects the difficulties of street dog testing, including standardisation in disturbance-prone environments, ecology-dependent adaptation of methods, and intrinsic differences between pet and free-ranging dogs. With some adaptations, this test battery can be valuable in investigating cognition and behavioural profiles in such an understudied population as free-ranging dogs.

Long-term memory of experienced jays facilitates problem-solving by naïve group members in the wild

Long-term memory affects animal fitness, especially in social species. In these species, the memory of group members facilitates the acquisition of novel foraging skills through social learning when naïve individuals observe and imitate the successful foraging behavior. Long-term memory and social learning also provide the framework for cultural behavior, a trait found in humans but very few other animal species. In birds, little is known about the duration of long-term memories for complex foraging skills, or the impact of long-term memory on group members. We tested whether wild jays remembered a complex foraging task more than 3 years after their initial experience and quantified the effect of this memory on naïve jay behavior. Experienced jays remembered how to solve the task and their behavior had significant positive effects on interactions by naïve group members at the task. This suggests that natural selection may favor long-term memory of solutions to foraging problems to facilitate the persistence of foraging skills that are specifically useful in the local environment in social birds with long lifespans and overlapping generations.

Dogs' expectations about occlusion events: from expectancy violation to exploration

Previous research on human infants has shown that violations of basic physical regularities can stimulate exploration, which may represent a type of hypothesis testing aimed at acquiring knowledge about new causal relationships. In this study, we examined whether a similar connection between expectancy violation and exploration exists in nonhuman animals. Specifically, we investigated how dogs react to expectancy violations in the context of occlusion events. Throughout three experiments, dogs exhibited longer looking times at expectancy-inconsistent events than at consistent ones. This finding was further supported by pupil size analyses in the first two eye-tracking experiments. Our results suggest that dogs expect objects to reappear when they are not obstructed by a screen and consider the size of the occluding screen in relation to the occluded object. In Experiment 3, expectancy violations increased the dogs' exploration of the target object, similar to the findings with human infants. We conclude that expectancy violations can provide learning opportunities for nonhuman animals as well.

Salivary Cortisol in Guide Dogs

Guide dogs work for extended periods and are exposed to multiple environmental stimuli that could lead to higher stress compared with companion dogs. Cortisol is the main hormone associated with stress in most mammals. This study included seven guide dogs and seven same-breed dogs that were trained as guide dogs but became companion dogs to compare their salivary cortisol levels before, during, and after a period of social isolation and exposure to a 110-decibel gunshot sound. Each dog was left alone in an empty room for 60 min. After 15 min, the dogs were exposed to the sound. We collected four saliva samples from each dog. The first one was taken 5 min before starting the social isolation period, and the following ones at 15, 30, and 45 min after the test started. A two-way ANOVA was used to compare the group effect and the time effect during isolation and noise exposure. The results showed higher levels of cortisol in the guide dogs compared with the companion dogs throughout the test. No differences were found in time or in the interaction between time and group. This suggests that being a guide dog increases levels of basal cortisol when compared with dogs that live as companion animals and family members.

The Science and Social Validity of Companion Animal Welfare: Functionally Defined Parameters in a Multidisciplinary Field

Social validity refers to the social significance and acceptability of intervention goals, procedures, and outcomes. Animal practitioners, who are often guided by the principles of ABA, lack the benefit of verbal participants (at least with respect to target animals) with which to assess a client's needs and preferences. The study of a learner's welfare is useful for determining areas where intervention is needed or how the learner feels about an intervention that is underway. Three tenets of animal welfare measurement include physiological function, naturalistic behavior, and affect, where affect refers to private events, including emotions, which are a function of the same variables and contingencies responsible for controlling public behavior. The development of new technologies allows us to look "under the skin" and account for subjective experiences that can now be observed objectively. We introduce the reader to tools available from the animal welfare sciences for the objective measurement of social validity from the learner's perspective.

Head-mounted mobile eye-tracking in the domestic dog: A new method

Humans rely on dogs for countless tasks, ranging from companionship to highly specialized detection work. In their daily lives, dogs must navigate a human-built visual world, yet comparatively little is known about what dogs visually attend to as they move through their environment. Real-world eye-tracking, or head-mounted eye-tracking, allows participants to freely move through their environment, providing more naturalistic results about visual attention while interacting with objects and agents. In dogs, real-world eye-tracking has the potential to inform our understanding of cross-species cognitive abilities as well as working dog training; however, a robust and easily deployed head-mounted eye-tracking method for dogs has not previously been developed and tested. We present a novel method for real-world eye-tracking in dogs, using a simple head-mounted mobile apparatus mounted onto goggles designed for dogs. This new method, adapted from systems that are widely used in humans, allows for eye-tracking during more naturalistic behaviors, namely walking around and interacting with real-world stimuli, as well as reduced training time as compared to traditional stationary eye-tracking methods. We found that while completing a simple forced-choice treat finding task, dogs look primarily to the treat, and we demonstrated the accuracy of this method using alternative gaze-tracking methods. Additionally, eye-tracking revealed more fine-grained time course information and individual differences in looking patterns.

Visual perception of emotion cues in dogs: a critical review of methodologies

Comparative studies of human-dog cognition have grown exponentially since the 2000's, but the focus on how dogs look at us (as well as other dogs) as social partners is a more recent phenomenon despite its importance to human-dog interactions. Here, we briefly summarise the current state of research in visual perception of emotion cues in dogs and why this area is important; we then critically review its most commonly used methods, by discussing conceptual and methodological challenges and associated limitations in depth; finally, we suggest some possible solutions and recommend best practice for future research. Typically, most studies in this field have concentrated on facial emotional cues, with full body information rarely considered. There are many challenges in the way studies are conceptually designed (e.g., use of non-naturalistic stimuli) and the way researchers incorporate biases (e.g., anthropomorphism) into experimental designs, which may lead to problematic conclusions. However, technological and scientific advances offer the opportunity to gather much more valid, objective, and systematic data in this rapidly expanding field of study. Solving conceptual and methodological challenges in the field of emotion perception research in dogs will not only be beneficial in improving research in dog-human interactions, but also within the comparative psychology area, in which dogs are an important model species to study evolutionary processes.

The current state of carnivore cognition

The field of animal cognition has advanced rapidly in the last 25 years. Through careful and creative studies of animals in captivity and in the wild, we have gained critical insights into the evolution of intelligence, the cognitive capacities of a diverse array of taxa, and the importance of ecological and social environments, as well as individual variation, in the expression of cognitive abilities. The field of animal cognition, however, is still being influenced by some historical tendencies. For example, primates and birds are still the majority of study species in the field of animal cognition. Studies of diverse taxa improve the generalizability of our results, are critical for testing evolutionary hypotheses, and open new paths for understanding cognition in species with vastly different morphologies. In this paper, we review the current state of knowledge of cognition in mammalian carnivores. We discuss the advantages of studying cognition in Carnivorans and the immense progress that has been made across many cognitive domains in both lab and field studies of carnivores. We also discuss the current constraints that are associated with studying carnivores. Finally, we explore new directions for future research in studies of carnivore cognition.

Dogs' ability to follow temporarily invisible moving objects: the ability to track and expect is shaped by experience

Visually tracking a moving object, even if it becomes temporarily invisible, is an important skill for animals living in complex environments. However, this ability has not been widely explored in dogs. To address this gap of knowledge and understand how experience contributes to such ability, we conducted two experiments using a violation of expectation paradigm. Dogs were shown an animation of a ball moving horizontally across a screen, passing behind an occluder, and reappearing with a timing that was faster, slower or congruent with its initial speed. In the first experiment, dogs (N = 15) were exposed to the incongruent conditions without prior experience; while in the second experiment, dogs (N = 37) were preliminarily exposed to the congruent stimulus. Dogs of the first experiment did not exhibit a surprise effect, as measured by latency to look away from the expected stimulus presentation area, in response to the incongruent conditions, suggesting they had not formed an expectation about the timing of reappearance. However, their latency to orient towards the reappearing ball depended on the condition, suggesting they were able, to some extent, to visually keep track of the stimulus' trajectory. Dogs of the second experiment were surprised when the ball stayed behind the occluder longer than expected, but showed no difference in latency to orient across conditions. This suggests they had overcome the visual tracking mechanism and had formed expectations about the timing of reappearance. In conclusion, dogs seem to use a low-level mechanism to keep visual track of a temporarily disappearing moving object, but experience is required to make expectation about its trajectory.

Recognition of rotated objects and cognitive offloading in dogs

Recognition of rotated images can challenge visual systems. Humans often diminish the load of cognitive tasks employing bodily actions (cognitive offloading). To investigate these phenomena from a comparative perspective, we trained eight dogs (Canis familiaris) to discriminate between bidimensional shapes. We then tested the dogs with rotated versions of the same shapes, while measuring their accuracy and head tilts. Although generalization to rotated stimuli challenged dogs (overall accuracy: 55%), three dogs performed differently from chance level with rotated stimuli. The amplitude of stimulus rotation did not influence dogs' performance. Interestingly, dogs tilted their head following the direction and amplitude of rotated stimuli. These small head movements did not influence their performance. Hence, we show that dogs might be capable of recognizing rotated 2D objects, but they do not use a cognitive offloading strategy in this task. This work paves the way to further investigation of cognitive offloading in non-human species.

Searching high and low: domestic dogs' understanding of solidity

Physical reasoning appears central to understanding how the world works, suggesting adaptive function across the animal kingdom. However, conclusive evidence for inferential reasoning about physical objects is limited to primates. We systematically tested a central feature-understanding of solidity-in domestic dogs, by adapting a validated procedure (the shelf task) previously used to test children and non-human primates. Dogs watched a treat dropped into an apparatus with a shelf either present (treat landing on the shelf) or absent (treat landing on the bottom surface) and chose where to search for it (above or below the shelf). Across four studies (n = 64), we manipulated visual access to the treat trajectory and apparatus interior. Dogs correctly inferred the location of treats using physical cues when the shelf was present (Study 1), and learned rapidly when visual cues of continuity were limited (Study 2), and when the shelf was absent (Study 3). Dogs were at chance when the apparatus was fully occluded, and the presence and absence of the shelf varied across trials within subjects, and showed no evidence of learning (Study 4). The findings of these four studies suggest that dogs may be able to make some inferences using solidity and continuity and do not exhibit proximity or gravity biases. However, dogs did not always search correctly from Trial 1, and failed to search correctly when the rewarded location varied within-subjects, suggesting a role for learning, and possible limits to their ability to make inferences about physical objects.

Recognizing and Mitigating Canine Stress during Animal Assisted Interventions

Animal-assisted Interventions (AAI) proliferated rapidly since clinicians and researchers first noted the positive effects animals have on people struggling with physical and mental health concerns. The intersection of AAI with the field of animal welfare evolved from considering animals’ basic needs, such as freedom from pain, to recognition that animals experience nuanced emotions. Current conceptualizations of the various roles of companion animals as an adjunct to treatments for humans emphasize not only the animals’ physical comfort and autonomy, but also their mental well-being and enjoyment of AAI activities. However, numerous challenges to effective monitoring of animals involved in AAI exist. This article focuses specifically on dogs, highlighting factors that may lead handlers and therapists to miss or ignore canine stress signals during human-animal interactions and offers strategies to recognize and ameliorate dogs’ distress more consistently. The primary goals of this discussion are to summarize the current thinking on canine well-being and to highlight practical applications of animal welfare principles in real-world AAI settings. The paper highlights contextual factors (e.g., physical setting, patient demand), human influences (e.g., desire to help), and intervention characteristics (e.g., presence or absence of a dog-specific advocate) that may promote or inhibit humans’ ability to advocate for therapy dogs during AAI activities. Deidentified examples of each of these factors are discussed, and recommendations are provided to mitigate factors that interfere with timely recognition and amelioration of canine distress.

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.

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.

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.

Of Great Apes and Magpies: Initiations into Animal Behaviour

Simple Summary

Animal encounters have been favourite subjects for a long time and it would scarcely be novel to report such stories for their own sake, even though the ones told here are dramatic enough to stand on their own. The questions addressed in this paper are twofold. The first question is: What influence may particular and dramatic animal encounters have on the human observer and how dependent is such a response on previously held attitudes? This paper provides three cases studies of extraordinary moments that changed the lives of the human participants and turned them into advocates of the species they had encountered. The next question asked is how we can be respectful of animals without anthropomorphising them and study them in ways that help us understand their abilities and their needs rather than impose questions that mean much to the human researcher but could be irrelevant to the species? The examples given here compare and contrast species that are especially close to us (great apes) with studies of those that are distant from us in their evolution (birds) and show how different attitudes change the questions that can be asked by scientists, demonstrably leading to new and even stunning results.

Abstract

This paper presents three case studies of exceptional human encounters with animals. These particular examples were selected because they enabled analysis of the underlying reasons that led the human participants to respond in new ways to their animal counterparts. The question asked here is whether sudden insights into the needs and abilities of an animal arises purely from an anthropocentric position as empathy because of genetic closeness (e.g., chimpanzees) or is something else and whether new insights can be applied to other phylogenetic orders not close to us, e.g., birds, and change research questions and implicit prejudices and stereotypes. Particularly in avian species, phylogenetically distant from humans, the prejudices (anthroprocentric position) and the belief in human uniqueness (human exceptionalism) might be greater than in the reactions to primates. Interestingly, in studies of great apes, contradictory opinions and controversies about cognitive abilities, especially when compared with humans, tend to be pronounced. Species appropriateness in test designs are desirable present and future goals but here it is suggested how different experiences can also lead to different questions that explode the myth of human uniqueness and then arrive at entirely different and new results in cognitive and affective abilities of the species under investigation.

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.

Dogs accurately track a moving object on a screen and anticipate its destination

The prediction of upcoming events is of importance not only to humans and non-human primates but also to other animals that live in complex environments with lurking threats or moving prey. In this study, we examined motion tracking and anticipatory looking in dogs in two eye-tracking experiments. In Experiment 1, we presented pet dogs (N = 14) with a video depicting how two players threw a Frisbee back and forth multiple times. The horizontal movement of the Frisbee explained a substantial amount of variance of the dogs' horizontal eye movements. With increasing duration of the video, the dogs looked at the catcher before the Frisbee arrived. In Experiment 2, we showed the dogs (N = 12) the same video recording. This time, however, we froze and rewound parts of the video to examine how the dogs would react to surprising events (i.e., the Frisbee hovering in midair and reversing its direction). The Frisbee again captured the dogs' attention, particularly when the video was frozen and rewound for the first time. Additionally, the dogs looked faster at the catcher when the video moved forward compared to when it was rewound. We conclude that motion tracking and anticipatory looking paradigms provide promising tools for future cognitive research with canids.

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.

Validity of Cognitive Tests for Non-human Animals: Pitfalls and Prospects

Comparative psychology assesses cognitive abilities and capacities of non-human animals and humans. Based on performance differences and similarities in various species in cognitive tests, it is inferred how their minds work and reconstructed how cognition might have evolved. Critically, such species comparisons are only valid and meaningful if the tasks truly capture individual and inter-specific variation in cognitive abilities rather than contextual variables that might affect task performance. Unlike in human test psychology, however, cognitive tasks for non-human primates (and most other animals) have been rarely evaluated regarding their measurement validity. We review recent studies that address how non-cognitive factors affect performance in a set of commonly used cognitive tasks, and if cognitive tests truly measure individual variation in cognitive abilities. We find that individual differences in emotional and motivational factors primarily affect performance via attention. Hence, it is crucial to systematically control for attention during cognitive tasks to obtain valid and reliable results. Aspects of test design, however, can also have a substantial effect on cognitive performance. We conclude that non-cognitive factors are a minor source of measurement error if acknowledged and properly controlled for. It is essential, however, to validate and eventually re-design several primate cognition tasks in order to ascertain that they capture the cognitive abilities they were designed to measure. This will provide a more solid base for future cognitive comparisons within primates but also across a wider range of non-human animal species.

Cognitive characteristics of 8- to 10-week-old assistance dog puppies

To characterize the early ontogeny of dog cognition, we tested 168 domestic dog, Canis familiaris, puppies (97 females, 71 males; mean age = 9.2 weeks) in a novel test battery based on previous tasks developed and employed with adolescent and adult dogs. Our sample consisted of Labrador retrievers, golden retrievers and Labrador × golden retriever crosses from 65 different litters at Canine Companions for Independence, an organization that breeds, trains and places assistance dogs for people with disabilities. Puppies participated in a 3-day cognitive battery that consisted of 14 tasks measuring different cognitive abilities and temperament traits such as executive function (e.g. inhibitory control, reversal learning, working memory), use of social cues, sensory discriminations and reactivity to and recovery from novel situations. At 8-10 weeks of age, and despite minimal experience with humans, puppies reliably used a variety of cooperative-communicative gestures from humans. Puppies accurately remembered the location of hidden food for delays of up to 20 s, and succeeded in a variety of visual, olfactory and auditory discrimination problems. They also showed some skill at executive function tasks requiring inhibitory control and reversal learning, although they scored lower on these tasks than is typical in adulthood. Taken together, our results confirm the early emergence of sensitivity to human communication in dogs and contextualize these skills within a broad array of other cognitive abilities measured at the same stage of ontogeny.

Brain gyrification in wild and domestic canids: Has domestication changed the gyrification index in domestic dogs?

Over the last 15 years, research on canid cognition has revealed that domestic dogs possess a surprising array of complex sociocognitive skills pointing to the possibility that the domestication process might have uniquely altered their brains; however, we know very little about how evolutionary processes (natural or artificial) might have modified underlying neural structure to support species-specific behaviors. Evaluating the degree of cortical folding (i.e., gyrification) within canids may prove useful, as this parameter is linked to functional variation of the cerebral cortex. Using quantitative magnetic resonance imaging to investigate the impact of domestication on the canine cortical surface, we compared the gyrification index (GI) in 19 carnivore species, including six wild canid and 13 domestic dog individuals. We also explored correlations between global and local GI with brain mass, cortical thickness, white and gray matter volume and surface area. Our results indicated that GI values for domestic dogs are largely consistent with what would be expected for a canid of their given brain mass, although more variable than that observed in wild canids. We also found that GI in canids is positively correlated with cortical surface area, cortical thickness and total cortical gray matter volumes. While we found no evidence of global differences in GI between domestic and wild canids, certain regional differences in gyrification were observed.

Investigating the use of sensory information to detect and track prey by the Sunda pangolin (Manis javanica) with conservation in mind

Pangolins are of conservation concern as one of the most heavily poached, yet least understood mammals. The Sunda pangolin (Manis javanica) in particular is a critically endangered species. Here, we investigate the behaviour of these pangolins, for the first time, using a battery of cognitive tasks based on a manipulation of available sensory information. In an object-choice task in which only one of two containers was baited with food, the pangolins were able to find the food with olfactory information alone (N = 2), but not with visual or acoustic information alone (N = 1). The single subject tested on all three domains was further tested on how he used smell to find food by providing him with an opportunity to find it from a controlled distance or by using scent trails as a guide. The results suggest that our subject may have the capacity to exploit scent trails left by prey which can be tracked to a final source, though we found no evidence to suggest that he had the ability to initiate hunts based on distant prey odors. Despite the small sample size, this is the first controlled experiment to investigate pangolin foraging behaviour and cognition, which may have implications for the future protection of pangolin habitat based on the location of prey species.

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.

Training pet dogs for eye-tracking and awake fMRI

In recent years, two well-developed methods of studying mental processes in humans have been successively applied to dogs. First, eye-tracking has been used to study visual cognition without distraction in unrestrained dogs. Second, noninvasive functional magnetic resonance imaging (fMRI) has been used for assessing the brain functions of dogs in vivo. Both methods, however, require dogs to sit, stand, or lie motionless while yet remaining attentive for several minutes, during which time their brain activity and eye movements are measured. Whereas eye-tracking in dogs is performed in a quiet and, apart from the experimental stimuli, nonstimulating and highly controlled environment, MRI scanning can only be performed in a very noisy and spatially restraining MRI scanner, in which dogs need to feel relaxed and stay motionless in order to study their brain and cognition with high precision. Here we describe in detail a training regime that is perfectly suited to train dogs in the required skills, with a high success probability and while keeping to the highest ethical standards of animal welfare-that is, without using aversive training methods or any other compromises to the dog's well-being for both methods. By reporting data from 41 dogs that successfully participated in eye-tracking training and 24 dogs IN fMRI training, we provide robust qualitative and quantitative evidence for the quality and efficiency of our training methods. By documenting and validating our training approach here, we aim to inspire others to use our methods to apply eye-tracking or fMRI for their investigations of canine behavior and cognition.

Cognitive Abilities of Dogs with Mucopolysaccharidosis I: Learning and Memory

Mucopolysaccharidosis I (MPS I) results from a deficiency of a lysosomal enzyme, alpha-L-iduronidase (IDUA). IDUA deficiency leads to glycosaminoglycan (GAG) accumulation resulting in cellular degeneration and multi-organ dysfunction. The primary aims of this pilot study were to determine the feasibility of cognitive testing MPS I affected dogs and to determine their non-social cognitive abilities with and without gene therapy. Fourteen dogs were tested: 5 MPS I untreated, 5 MPS I treated, and 4 clinically normal. The treated group received intrathecal gene therapy as neonates to replace the IDUA gene. Cognitive tests included delayed non-match to position (DNMP), two-object visual discrimination (VD), reversal learning (RL), attention oddity (AO), and two-scent discrimination (SD). Responses were recorded as correct, incorrect, or no response, and analyzed using mixed effect logistic regression analysis. Significant differences were not observed among the three groups for DNMP, VD, RL, or AO. The MPS I untreated dogs were excluded from AO testing due to failing to pass acquisition of the task, potentially representing a learning or executive function deficit. The MPS I affected group (treated and untreated) was significantly more likely to discriminate between scents than the normal group, which may be due to an age effect. The normal group was comprised of the oldest dogs, and a mixed effect logistic model indicated that older dogs were more likely to respond incorrectly on scent discrimination. Overall, this study found that cognition testing of MPS I affected dogs to be feasible. This work provides a framework to refine future cognition studies of dogs affected with diseases, including MPS I, in order to assess therapies in a more comprehensive manner.

Odor span task in dogs (Canis familiaris)

Working memory is essential for organisms to solve problems related to their survival and to adapt to changes in their environment. Researchers sought to create a non-human model of working memory that could be used to better understand its predictive value and underlying brain function. Several of these studies were conducted using the odor span task (OST) with rodents, and here, we present the first OST with domestic dogs (n = 6). The OST is an incrementing non-match-to-sample task in which dogs were presented with both a session novel (S +) and a previously encountered (S -) odor on each trial. A response to the session novel odor was always reinforced. Upon meeting training criterion on sessions with 24 trials or odors to remember, the dogs were tested on the OST with up to 72 odors to remember in the session. All dogs learned the OST and displayed accurate performance (≥ 79%) for the largest set size of 72 odors. In an analysis focused on the effect of intervening odors (i.e., the number of trials since the S - was last encountered), dogs demonstrated above-chance performance for up to eight intervening odors. The implications of these findings are discussed in the context of dog working memory for odors.

Illusory contour perception in domestic dogs

One way to better understand how animals visually perceive their environment is to assess the way in which visual information is interpreted and adapted based on preconceptions. Domestic dogs represent a unique species in which to evaluate visual perception as recent findings suggest they may differ from humans and other animal species in terms of their susceptibility to geometric visual illusions. Dogs have demonstrated human-like, reversed, and null susceptibility depending on the type of illusion. To further evaluate how dogs perceive their environment, it is necessary to perform additional assessments of visual perception. One such assessment is the perceptual filling-in of figures, which may be invoked when presented with illusory contours. Six dogs were assessed on their perception of the Ehrenstein illusory contour illusion in a two-choice size-discrimination task. Dogs, as a group, demonstrated equivocal perception of illusory contours. Some individual dogs, however, demonstrated human-like perception of the subjective contours, providing preliminary evidence that this species is capable of perceiving illusory contour illusions, thereby improving the current understanding of canine visual perception capabilities. Additional assessments using alternative illusory contour illusions are needed to clarify these results and identify features that underpin the individual differences observed.

Genetic Pathways of Aging and Their Relevance in the Dog as a Natural Model of Human Aging

Aging research has experienced a burst of scientific efforts in the last decades as the growing ratio of elderly people has begun to pose an increased burden on the healthcare and pension systems of developed countries. Although many breakthroughs have been reported in understanding the cellular mechanisms of aging, the intrinsic and extrinsic factors that contribute to senescence on higher biological levels are still barely understood. The dog, Canis familiaris, has already served as a valuable model of human physiology and disease. The possible role the dog could play in aging research is still an open question, although utilization of dogs may hold great promises as they naturally develop age-related cognitive decline, with behavioral and histological characteristics very similar to those of humans. In this regard, family dogs may possess unmatched potentials as models for investigations on the complex interactions between environmental, behavioral, and genetic factors that determine the course of aging. In this review, we summarize the known genetic pathways in aging and their relevance in dogs, putting emphasis on the yet barely described nature of certain aging pathways in canines. Reasons for highlighting the dog as a future aging and gerontology model are also discussed, ranging from its unique evolutionary path shared with humans, its social skills, and the fact that family dogs live together with their owners, and are being exposed to the same environmental effects.

A wolfdog point of view on the impossible task paradigm

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

The dog (Canis familiaris) as a translational model of autism: It is high time we move from promise to reality

Selecting appropriate animal models for a particular human phenomenon is a difficult but important challenge. The difficulty lies in finding animal behaviors that are not only sufficiently relevant and analog to the complex human symptoms (face validity) but also have similar underlying biological and etiological mechanisms (translational or construct validity), and have "human-like" responses to treatment (predictive validity). Over the past several years, the domestic dog (Canis familiaris) has become increasingly proposed as a model for comparative and translational neuroscience. In parallel to the recent advances in canine behavior research, dogs have also been proposed as a model of many human neuropsychiatric conditions, including autism spectrum disorder (ASD). In this opinion paper we will shortly discuss the challenging nature of autism research then summarize the different neurocognitive frameworks for ASD making the case for a canine model of autism. The translational value of a dog model stems from the recognition that (a) there is a large inter-individual variability in the manifestation of dogs' social cognitive abilities including both high and low phenotypic extremes; (b) the phenotypic similarity between the dog and human symptoms are much higher than between the rodent and human symptoms; (c) the symptoms are functionally analogous to the human condition; and (d) more likely to have similar etiology. This article is categorized under: Psychology > Comparative Psychology Cognitive Biology > Evolutionary Roots of Cognition.

What do dogs (Canis familiaris) see? A review of vision in dogs and implications for cognition research

Over the last 20 years, a large amount of research has been conducted in an attempt to uncover the cognitive abilities of the domestic dog. While substantial advancements have been made, progress has been impeded by the fact that little is known about how dogs visually perceive their external environment. It is imperative that future research determines more precisely canine visual processing capabilities, particularly considering the increasing number of studies assessing cognition via paradigms requiring vision. This review discusses current research on visual cognition and emphasizes the importance of understanding dog visual processing. We review several areas of vision research in domestic dogs, such as sensitivity to light, visual perspective, visual acuity, form perception, and color vision, with a focus on how these abilities may affect performance in cognition tasks. Additionally, we consider the immense diversity seen in dog morphology and explore ways in which these physical differences, particularly in facial morphology, may result in, or perhaps even be caused by, different visual processing capacities in dogs. Finally, we suggest future directions for research in dog vision and cognition.

In what sense are dogs special? Canine cognition in comparative context

The great increase in the study of dog cognition in the current century has yielded insights into canine cognition in a variety of domains. In this review, we seek to place our enhanced understanding of canine cognition into context. We argue that in order to assess dog cognition, we need to regard dogs from three different perspectives: phylogenetically, as carnivoran and specifically a canid; ecologically, as social, cursorial hunters; and anthropogenically, as a domestic animal. A principled understanding of canine cognition should therefore involve comparing dogs' cognition with that of other carnivorans, other social hunters, and other domestic animals. This paper contrasts dog cognition with what is known about cognition in species that fit into these three categories, with a particular emphasis on wolves, cats, spotted hyenas, chimpanzees, dolphins, horses, and pigeons. We cover sensory cognition, physical cognition, spatial cognition, social cognition, and self-awareness. Although the comparisons are incomplete, because of the limited range of studies of some of the other relevant species, we conclude that dog cognition is influenced by the membership of all three of these groups, and taking all three groups into account, dog cognition does not look exceptional.

Behavioural responses to unexpected changes in reward quality

Successive negative contrast (SNC) effects are changes in anticipatory or consummatory behaviour when animals unexpectedly receive a lower value reward than they have received previously. SNC effects are often assumed to reflect frustration and appear to be influenced by background affective state. However, alternative explanations of SNC, such as the functional-search hypothesis, do not necessarily imply an aversive affective state. We tested 18 dogs in a SNC paradigm using a patch foraging task. Dogs were tested in two conditions, once with the low value reward in all of five trials (unshifted) and once when reward value was altered between high and low (shifted). Following a reward downshift, subjects showed a SNC effect by switching significantly more often between patches compared to the unshifted condition. However, approach latency, foraging time and quantity consumed did not differ between conditions, suggesting non-affective functional search behaviour rather than frustration. There was no relationship between strength of SNC and anxiety-related behaviours as measured in a novel object test and a personality questionnaire (C-BARQ). However, associations with the C-BARQ scores for Trainability and Stranger directed aggression suggest a possible link with behavioural flexibility and coping style. While reward quality clearly affects incentive motivation, the relationship between SNC, frustration and background affective state requires further exploration.

Awake fMRI Reveals Brain Regions for Novel Word Detection in Dogs

How do dogs understand human words? At a basic level, understanding would require the discrimination of words from non-words. To determine the mechanisms of such a discrimination, we trained 12 dogs to retrieve two objects based on object names, then probed the neural basis for these auditory discriminations using awake-fMRI. We compared the neural response to these trained words relative to "oddball" pseudowords the dogs had not heard before. Consistent with novelty detection, we found greater activation for pseudowords relative to trained words bilaterally in the parietotemporal cortex. To probe the neural basis for representations of trained words, searchlight multivoxel pattern analysis (MVPA) revealed that a subset of dogs had clusters of informative voxels that discriminated between the two trained words. These clusters included the left temporal cortex and amygdala, left caudate nucleus, and thalamus. These results demonstrate that dogs' processing of human words utilizes basic processes like novelty detection, and for some dogs, may also include auditory and hedonic representations.

Heart Rate and Heart Rate Variability during Sleep in Family Dogs (Canis familiaris). Moderate Effect of Pre-Sleep Emotions

Simple Summary

It is common knowledge that negative emotions in humans are accompanied by both impaired subjective experience as well as maladaptive changes in behavior and physiology. The present paper investigates heart rate—one of the most commonly used emotion-related physiology measures—in the family dog, with the aim of uncovering its potential relationship with emotions. Sleep recordings were conducted following a positive versus a negative social interaction, as sleep alternations are one of the most conspicuous changes in response to negative affect. We observed differences in heart rate following the positive versus negative interactions, however these were only apparent during wakefulness, but not during sleep.

Abstract

The domestic dog (Canis familiaris) has been shown to both excel in recognising human emotions and produce emotion-related vocalisations and postures that humans can easily recognise. However, little is known about the effect of emotional experiences on subsequent sleep physiology, a set of phenomena heavily interrelated with emotions in the case of humans. The present paper examines heart rate (HR) and heart rate variability (HRV) during dogs’ sleep, measures that are influenced by both positive and negative emotions in awake dogs. In Study I, descriptive HR and HRV data is provided on N = 12 dogs about the different sleep stages (wake, drowsiness, non-rapid eye movement (non-REM), REM; scoring based on electroencephalogram (EEG) data). We conclude that wakefulness is characterised by higher HR and lower HRV compared to all sleep stages. Furthermore, drowsiness is characterised by higher HR and lower HRV than non-REM and REM, but only if the electrocardiogram (ECG) samples are taken from the first occurrence of a given sleep stage, not when the longest periods of each sleep stage are analysed. Non-REM and REM sleep were not found to be different from each other in either HR or HRV parameters. In Study II, sleep HR and HRV measures are compared in N = 16 dogs after a positive versus negative social interaction (within-subject design). The positive social interaction consisted of petting and ball play, while the negative social interaction was a mixture of separation, threatening approach and still face test. Results are consistent with the two-dimensional emotion hypothesis in that following the intense positive interaction more elevated HR and decreased HRV is found compared to the mildly negative (lower intensity) interaction. However, although this trend can be observed in all sleep stages except for REM, the results only reach significance in the wake stage. In sum, the present findings suggest that HR and HRV are possible to measure during dogs’ sleep, and can potentially be used to study the effect of emotions not only during but also after such interactions.

Companion and free-ranging Bali dogs: Environmental links with personality traits in an endemic dog population of South East Asia

Dogs living on Bali Island have been free-ranging for thousands of years. A large group of expatriates sometimes adopt Bali dogs and keep them restricted to their houses and backyards, as is typical in modern western cultures. This provides us with the unique opportunity to compare the personality traits of dogs to their lifestyle either living as human companions or as free-ranging animals, exploring at the same time the impact of demographic variables (such as age, sex, and neutered status) on personality. After controlling for internal consistency of the scales and between-observer variation, we found that free-ranging Bali dogs were rated as less active, less excitable, less aggressive towards animals, and less inclined to chase animals or humans than Bali dogs living as human companions. Among free-ranging dogs, females were found to be more excitable. Females in the whole sample were also more fearful of people. The results of this preliminary study suggest that a change in lifestyle, i.e. being adopted, and living in a confined environment has negative consequences on some canine personality traits, such as activity/excitability, aggression towards animals, and prey drive.