Synchronous citizen science with dogs.

Citizen science approaches have grown in popularity over the years, partly due to their ability to reach a wider audience and produce more generalizable samples. In dogs, these studies, though, have been limited in their controls over materials or experimental protocols, with guardians typically reporting results without researcher supervision. Over two studies, we explored and validated a synchronous citizen science approach. We had dog guardians act as experimenters while being supervised by a researcher over Zoom. In study 1, we demonstrated that synchronous citizen science produced equivalent levels of performance to in-lab designs in a choice task. Consistent with past in-lab research, dogs selected a treat (vs. an empty plate) in a two-alternative forced-choice task. In study 2, we showed that Zoom methods are also appropriate for studies utilizing looking time measures. We explored dogs' looking behaviors when a bag of treats was placed in an unreachable location, and dogs' guardians were either attentive or inattentive while dogs attempted to retrieve the treats. Consistent with past work, dogs in the attentive condition looked at their guardian for longer periods and had a shorter latency to first look than dogs in the inattentive condition. Overall, we have demonstrated that synchronous citizen science studies with dogs are feasible and produce valid results consistent with those found in a typical lab setting.

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.

Effects of maternal investment, temperament, and cognition on guide dog success.

A continuing debate in studies of social development in both humans and other animals is the extent to which early life experiences affect adult behavior. Also unclear are the relative contributions of cognitive skills ("intelligence") and temperament for successful outcomes. Guide dogs are particularly suited to research on these questions. To succeed as a guide dog, individuals must accomplish complex navigation and decision making without succumbing to distractions and unforeseen obstacles. Faced with these rigorous demands, only ∼70% of dogs that enter training ultimately achieve success. What predicts success as a guide dog? To address these questions, we followed 98 puppies from birth to adulthood. We found that high levels of overall maternal behavior were linked with a higher likelihood of program failure. Furthermore, mothers whose nursing style required greater effort by puppies were more likely to produce successful offspring, whereas mothers whose nursing style required less effort were more likely to produce offspring that failed. In young adults, an inability to solve a multistep task quickly, compounded with high levels of perseveration during the task, was associated with failure. Young adults that were released from the program also appeared more anxious, as indicated by a short latency to vocalize when faced with a novel object task. Our results suggest that both maternal nursing behavior and individual traits of cognition and temperament are associated with guide dog success.

The cocktail party effect in the domestic dog (Canis familiaris).

Like humans, canine companions often find themselves in noisy environments, and are expected to respond to human speech despite potential distractors. Such environments pose particular problems for young children, who have limited linguistic knowledge. Here, we examined whether dogs show similar difficulties. We found that dogs prefer their name to a stress-matched foil in quiet conditions, despite hearing it spoken by a novel talker. They continued to prefer their name in the presence of multitalker human speech babble at signal-to-noise levels as low as 0 dB, when their name was the same intensity as the foil. This surpasses the performance of 1-year-old infants, who fail to prefer their name to a foil at 0 dB (Newman in Dev Psychol 41(2):352-362, 2005). Overall, we find better performance at name recognition in dogs that were trained to do tasks for humans, like service dogs, search-and-rescue dogs, and explosives detection dogs. These dogs were of several different breeds, and their tasks were widely different from one another. This suggests that their superior performance may be due to generally more training and better attention. In summary, these results demonstrate that dogs can recognize their name even in relatively difficult levels of multitalker babble, and that dogs who work with humans are especially adept at name recognition in comparison with companion dogs. Future studies will explore the effect of different types of background noise on word recognition in dogs.

Motoric self-regulation by sled dogs and pet dogs and the acute effect of carbohydrate source in sled dogs.

Inhibitory control is a term used to envelop a collection of processes that allow an organism to refrain from engaging in an inappropriate prepotent or responsive behavior. Studies have examined the propensity of inhibitory control by nonhuman animals, from the cognitively complex processes involved in self-control to potentially less cognitively taxing processes such as motoric self-regulation. Focusing on canines, research has suggested that the domestication process as well as experiences during ontogeny contribute to inhibitory control. Diet may also play an important role in an individual's ability to self-regulate. This study examined this possibility by investigating motoric self-regulation in sled dogs, using three well-established tasks (i.e., A-not-B Bucket, Cylinder, and A-not-B Barrier tasks), performed after consumption of one of three dietary treatments with different glycemic index values. We also compared the performance of sled dogs during these tasks with results previously obtained from pet dogs. Overall, the results show many similarities in the performance of sled dogs and pet dogs on the motoric self-regulation tasks, with the notable exception that sled dogs may have a stronger spatial perseveration during the A-not-B Bucket task. Previous research findings reporting a lack of correlation among these tasks are also supported. Finally, during the early postprandial phase (period after consumption), dietary treatments with different glycemic index values did not influence self-regulatory performance for sled dogs.

Dogs and wolves do not differ in their inhibitory control abilities in a non-social test battery.

Being able to inhibit certain behaviours is of clear advantage in various situations. In particular, it has been suggested that inhibitory control plays a role in problem-solving and cooperation. Interspecific differences in the capacity for inhibitory control have been attributed to social and ecological factors, while one additional factor, namely domestication, has received only little attention so far. Dogs are an interesting species to test the effects of socio-ecological factors and also the influence of domestication on inhibitory control abilities. While dogs might have been selected for enhanced inhibition skills during domestication, the predictions derived from their socio-ecological background are reversed. Wolves are cooperative hunters and breeders, while dogs predominately scavenge and raise their young alone, accordingly, it would be predicted that dogs show impaired inhibitory control abilities since they no longer rely on these coordinated actions. To test these hypotheses, we assessed inhibitory control abilities in dogs and wolves raised and kept under similar conditions. Moreover, considering the problem of context-specificity in inhibitory control measures, we employed a multiple-test-approach. In line with previous studies, we found that the single inhibition tests did not correlate with each other. Using an exploratory approach, we found three components that explained the variation of behaviours across tests: motivation, flexibility, and perseveration. Interestingly, these inhibition components did not differ between dogs and wolves, which contradicts the predictions based on their socio-ecological backgrounds but also suggests that at least in tasks with minimal human influence, domestication did not affect dogs' inhibitory control abilities, thus raising questions in regard to the selection processes that might have affected inhibitory control abilities during the course of domestication.

Comparing interspecific socio-communicative skills of socialized juvenile dogs and miniature pigs.

Previous research proves dogs' outstanding success in socio-communicative interactions with humans; however, little is known about other domestic species' interspecific skills when kept as companion animals. Our aim was to assess highly socialized young miniature pigs' spontaneous reactions in interactions with humans in direct comparison with that of young family dogs. All subjects experienced similar amount of socialization in human families. In Study 1, we investigated the appearance of human-oriented behaviours without the presence of food (Control condition) when a previously provided food reward was withheld (Food condition). In Study 2, we measured responsiveness to two types of the distal pointing gesture (dynamic sustained and momentary) in a two-way object choice test. In the Control condition of Study 1, the duration of pigs' and dogs' orientation towards and their frequency of touching the human's body was similar. In the Food condition, these behaviours and orienting to the human's face were intensified in both species. However, pigs exhibited face-orientation to an overall lesser extent and almost exclusively in the Food condition. In Study 2, only dogs relied spontaneously on the distal dynamic-sustained pointing gesture, while all pigs developed side bias. The results suggest that individual familiarization to a human environment enables the spontaneous appearance of similar socio-communicative behaviours in dogs and pigs, however, species predispositions might cause differences in the display of specific signals as well as in the success of spontaneously responding to certain types of the human pointing gestures.

Can dogs use vocal intonation as a social referencing cue in an object choice task?

Evidence from the literature indicates that dogs' choices can be influenced by human-delivered social cues, such as pointing, and pointing combined with facial expression, intonation (i.e., rising and falling voice pitch), and/or words. The present study used an object choice task to investigate whether intonation conveys unique information in the absence of other salient cues. We removed facial expression cues and speech information by delivering cues with the experimenter's back to the dog and by using nonword vocalizations. During each trial, the dog was presented with pairs of the following three vocal cues: Positive (happy-sounding), Negative (sad-sounding), and Breath (neutral control). In Experiment 1, where dogs received only these vocal cue pairings, dogs preferred the Positive intonation, and there was no difference in choice behavior between Negative or Breath. In Experiment 2, we included a point cue with one of the two vocal cues in each pairing. Here, dogs preferred containers receiving pointing cues as well as Negative intonation, and preference was greatest when both of these cues were presented together. Taken together, these findings indicate that dogs can indeed extract information from vocal intonation alone, and may use intonation as a social referencing cue. However, the effect of intonation on behavior appears to be strongly influenced by the presence of pointing, which is known to be a highly salient visual cue for dogs. It is possible that in the presence of a point cue, intonation may shift from informative to instructive.

A case for methodological overhaul and increased study of executive function in the domestic dog (Canis lupus familiaris).

Executive function (EF) allows for self-regulation of behavior including maintaining focus in the face of distraction, inhibiting behavior that is suboptimal or inappropriate in a given context, and updating the contents of working memory. While EF has been studied extensively in humans, it has only recently become a topic of research in the domestic dog. In this paper, I argue for increased study of dog EF by explaining how it might influence the owner-dog bond, human safety, and dog welfare, as well as reviewing the current literature dedicated to EF in dogs. In "EF and its Application to "Man's Best Friend" section, I briefly describe EF and how it is relevant to dog behavior. In "Previous investigations into EF in dogs" section, I provide a review of the literature pertaining to EF in dogs, specifically tasks used to assess abilities like inhibitory control, cognitive flexibility, and working memory capacity. In "Insights and limitations of previous studies" section, I consider limitations of existing studies that must be addressed in future research. Finally, in "Future directions" section, I propose future directions for meaningful research on EF in dogs.

Do dogs exhibit jealous behaviors when their owner attends to their companion dog?

Jealousy appears to have clear adaptive functions across species: it emerges when an important social relationship with a valued social partner is threatened by third-party that is perceived as a rival. Dyads of dogs living together and their owners were tested adapting a procedure devised to study jealousy in young human siblings. Owners at first ignored both dogs while reading a magazine (Control episode), and then petted and praised one of the dogs while ignoring the other, and vice versa (Experimental episodes). We found several differences in the dogs' behavior between the Experimental episodes and the Control episode, even though only monitoring (gazing at the owner) was exhibited for a significantly greater amount of time in the Experimental episodes. Remarkable individual behavioral differences emerged, suggesting that the dogs' reactions could be influenced by the relationships that they establish with their owner and the companion dog. Overall, current results do not clearly support our prediction that the ignored dogs would exhibit more behaviors aimed at regaining the owner's attention when their owner directed attention and care to a companion dog, compared to the control situation. The great intra- and inter-dyad behavioral variability and the choice to test cohabiting dogs could have prevented the emergence of a clear jealous reaction. These findings do not exclude that dogs may exhibit a primordial form of jealousy in a realistic situation, but an additional research is needed to fully gauge which situations, if any, could trigger jealousy in dogs and to rule out alternative explanations.

Should I fetch one or the other? A study on dogs on the object choice in the bimodal contrasting paradigm.

The present study assessed how dogs weigh gestural versus verbal information communicated to them by humans in transitive actions. The dogs were trained by their owners to fetch an object under three conditions: a bimodal congruent condition characterized by using gestures and voices simultaneously; a unimodal gestural condition characterized by using only gestures; and a unimodal verbal condition characterized by using only voices. An additional condition, defined as a bimodal incongruent condition, was later added, in which the gesture contrasted with the verbal command, that is, the owner indicated an object while pronouncing the name of the other object visible to dogs. In the incongruent condition, seven out of nine dogs choose to follow the gestural indication and performed above chance, two were at chance, whereas none of the dogs followed the verbal cues above chance. The dogs, as a group, performed above chance the gestural command in 73.6% of cases. The analysis of latencies in the above-mentioned four conditions exhibited significant differences. The unimodal verbal and the gestural conditions recorded a slower performance than both the bimodal incongruent and congruent conditions. No statistical differences were observed between the unimodal and bimodal conditions. Our results demonstrate that dogs, trained to respond equally well to gestural and verbal commands, choose to follow the indication provided by the gestural command than the verbal one to a significant extent in transitive actions. Furthermore, the responses to bimodal conditions were found to be quicker than the unimodal ones.

Working dogs transfer different tasks in reciprocal cooperation.

Direct reciprocity can establish stable cooperation among unrelated individuals. It is a common assumption of direct reciprocity models that agents exchange like with like, but this is not necessarily true for natural interactions. It is yet unclear whether animals apply direct reciprocity rules when successive altruistic help involves different tasks. Here, we tested whether working dogs transfer help from one to another cooperative task in an iterated prisoner's dilemma paradigm. In our experiment, individual dogs received help to obtain food from a conspecific, which involved a specific task. Subsequently, the focal subject could return received favour by using a different task. Working dogs transferred the cooperative experience received through one task by applying an alternative task when they helped a previously cooperative partner. By contrast, they refrained from helping previously defecting partners. This suggests that dogs realize the cooperative act of a conspecific, which changes their propensity to provide help to that partner by different means. The ability of animals to transfer different tasks when helping a social partner by satisfying the criteria of direct reciprocity might explain the frequent occurrence of reciprocal cooperation in nature.

Wearable sensor shown to specifically quantify pruritic behaviors in dogs.

BACKGROUND: Wearable technology is an exciting new field in humans and animals. In dogs activity monitors have helped to provide objective measurement tools where pet owner observation had been the only source of information. Previous research has focused on measuring overall activity versus rest. This has been relatively useful in determining changes in activity in orthopedic disease or post-surgical cases [Malek et al., BMC Vet Res 8:185, 2012, Yashari et al., BMC Vet Res 11:146, 2015]. Assessment of pruritus via changes in activity, however, requires an assumption that increased activity is due to scratching or other pruritic behaviors. This is an inaccurate method with obvious flaws as other behaviors may also register as greater activity. The objective of this study was to validate the ability of a multidimensional high frequency sensor and advanced computer analysis system, (Vetrax®, AgLogica Holdings, Inc., Norcross, GA, USA) to specifically identify pruritic behaviors (scratching and head shaking). To establish differences between behaviors, sensor and time stamped video data were collected from 361 normal and pruritic dogs. Video annotations were made by two observers independently, while blinded to sensor data, and then evaluated for agreement. Annotations that agreed between the two were used for further analysis. The annotations specified behaviors at specific times in order to compare with sensor data. A computer algorithm was developed to interpret and differentiate between these behaviors. Test subject data was then utilized to test and score the system's ability to accurately predict behaviors. RESULTS: Results for prediction of head shaking behavior included sensitivity and specificity of 72.16% and 99.78% respectively. Analysis of scratching produced sensitivity and specificity of 76.85% and 99.73% respectively. These results illustrate the ability of the system to accurately report both scratching and head shaking with an overall accuracy of 99.24% and 99.56% respectively. CONCLUSIONS: This study validates the use of this system to accurately and objectively report scratching and head shaking in dogs. While a small portion of scratching or head shaking behaviors may be missed, as indicated by the sensitivity, when detected, the confidence that these behaviors occurred is extremely high. These factors make this system a very useful tool for objective assessment of pruritus in clinical and research settings.

Cognitive Aging in Dogs.

A decline in the physical or mental health of older dogs can be a challenge for the owners, whose relationship with their dog is compromised by the cognitive and behavioral changes in their dogs. Although dog owners tend to consider many physiological and behavioral changes in old dogs as part of the normal aging process, it is important to differentiate between normal aging and pathologic aging, since behavioral changes may be the first indication of declining health and welfare in old dogs. Most reviews on cognitive aging in dogs have focused on translational approaches to human Alzheimer's disease; from a practical perspective, however, understanding normal cognitive aging in pet dogs and screening cognitively affected dogs are important in their own right. Here we review the literature on different cognitive functions that decline during aging, signs of cognitive dysfunction, screening methods, and preventive measures for age-related cognitive decline. Moreover, we discuss the drawbacks of using questionnaires as subjective measures of aging and propose the development of objective methods to distinguish normal cognitive aging from severe cognitive dysfunction. We suggest that multi-targeted approaches that combine owner-evaluated questionnaires with neuropsychological tests can be most effective in screening cognitively affected dogs from normally aging dogs. Regarding preventive measures, we conclude that combinations of dietary intervention and behavioral enrichment may be more beneficial than single-pathway manipulations in delaying cognitive aging or retaining various cognitive functions during aging.

Advances in neuroscience imply that harmful experiments in dogs are unethical.

Functional MRI (fMRI) of fully awake and unrestrained dog 'volunteers' has been proven an effective tool to understand the neural circuitry and functioning of the canine brain. Although every dog owner would vouch that dogs are perceptive, cognitive, intuitive and capable of positive emotions/empathy, as indeed substantiated by ethological studies for some time, neurological investigations now corroborate this. These studies show that there exists a striking similarity between dogs and humans in the functioning of the caudate nucleus (associated with pleasure and emotion), and dogs experience positive emotions, empathic-like responses and demonstrate human bonding which, some scientists claim, may be at least comparable with human children. There exists an area analogous to the 'voice area' in the canine brain, enabling dogs to comprehend and respond to emotional cues/valence in human voices, and evidence of a region in the temporal cortex of dogs involved in the processing of faces, as also observed in humans and monkeys. We therefore contend that using dogs in invasive and/or harmful research, and toxicity testing, cannot be ethically justifiable.

Inequity aversion in dogs: a review.

The study of inequity aversion in animals debuted with a report of the behaviour in capuchin monkeys (Cebus apella). This report generated many debates following a number of criticisms. Ultimately, however, the finding stimulated widespread interest, and multiple studies have since attempted to demonstrate inequity aversion in various other non-human animal species, with many positive results in addition to many studies in which no response to inequity was found. Domestic dogs represent an interesting case as, unlike many primates, they do not respond negatively to inequity in reward quality but do, however, respond negatively to being unrewarded in the presence of a rewarded partner. Numerous studies have been published on inequity aversion in dogs in recent years. Combining three tasks and seven peer-reviewed publications, over 140 individual dogs have been tested in inequity experiments. Consequently, dogs are one of the best studied species in this field and could offer insights into inequity aversion in other non-human animal species. In this review, we summarise and critically evaluate the current evidence for inequity aversion in dogs. Additionally, we provide a comprehensive discussion of two understudied aspects of inequity aversion, the underlying mechanisms and the ultimate function, drawing on the latest findings on these topics in dogs while also placing these developments in the context of what is known, or thought to be the case, in other non-human animal species. Finally, we highlight gaps in our understanding of inequity aversion in dogs and thereby identify potential avenues for future research in this area.

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.

More evidence that less is better: Sub-optimal choice in dogs.

The less-is-better effect is a preference for the lesser of two alternatives sometimes observed when they are evaluated separately. For example, a dinner service of 24 intact pieces might be judged to be more valuable than a 40-piece dinner service containing nine broken pieces. Pattison and Zentall (Animal Cognition, 17: 1019-1022, 2014) reported similar sub-optimal choice behavior in dogs using a simultaneous choice procedure. Given a choice between a single high-value food item (cheese) or an equivalent high-value item plus a lower-value food item (carrot), their dogs chose the individual item. In a subsequent test, the dogs preferred two high-value items to a single high-value item, suggesting that avoidance of multiple items did not cause the sub-optimal choice behavior. In two experiments, we replicated Pattison and Zentall's procedure while including additional controls. In Experiment 1, habituation of neophobia for multiple items was controlled for by intermixing the two types of test trial within a single experimental session. In Experiment 2, we controlled for avoidance of heterogeneous rewards by including test trials in which a choice was offered between the combination of items and a single low-value item. In both experiments we observed sub-optimal choice behavior which could not be explained by either of these putative mechanisms. Our results, as well as those of Pattison and Zentall, are consistent with the suggestion that dogs' assessment of the total value of multiple items is based, at least partly, on their average quality.

Behavioral synchronization and affiliation: Dogs exhibit human-like skills.

Behavioral synchronization is evolutionary adaptive, fostering social cohesion. In humans, affiliation between partners is associated with a high level of behavioral synchronization; people show increased affiliation towards people who synchronize with them. Surprisingly, until recently, little was known about these phenomena at an interspecific level, which is, however, essential to better understand the respective roles of evolution and ontogeny. After presenting why dog-human dyads are a relevant biological model to study this field of social cognition, we review the recent findings about dog-human behavioral synchronization. We summarize recently published findings on behavioral synchronization and affiliation between dogs and humans. We also review results showing that genetic selection modulates behavioral synchronization propensity in dogs, emphasizing the role of genetic selection on dog's social behaviors towards humans. Finally, we discuss the possible evolutionary influences and proximate mechanisms of this phenomenon. We conclude that, as in humans, behavioral synchronization acts as a social glue between dogs and humans. After dogs' ability to use human-directional cues or to produce referential cues towards humans, we evidenced a new human-like social process in the dog, at the interspecfic level with humans.

Truth is in the eye of the beholder: Perception of the Müller-Lyer illusion in dogs.

Visual illusions are objects that are made up of elements that are arranged in such a way as to result in erroneous perception of the objects' physical properties. Visual illusions are used to study visual perception in humans and nonhuman animals, since they provide insight into the psychological and cognitive processes underlying the perceptual system. In a set of three experiments, we examined whether dogs were able to learn a relational discrimination and to perceive the Müller-Lyer illusion. In Experiment 1, dogs were trained to discriminate line lengths using a two-alternative forced choice procedure on a touchscreen. Upon learning the discrimination, dogs' generalization to novel exemplars and the threshold of their abilities were tested. In the second experiment, dogs were presented with the Müller-Lyer illusion as test trials, alongside additional test trials that controlled for overall stimulus size. Dogs appeared to perceive the illusion; however, control trials revealed that they were using global size to solve the task. Experiment 3 presented modified stimuli that have been known to enhance perception of the illusion in other species. However, the dogs' performance remained the same. These findings reveal evidence of relational learning in dogs. However, their failure to perceive the illusion emphasizes the importance of using a full array of control trials when examining these paradigms, and it suggests that visual acuity may play a crucial role in this perceptual phenomenon.