A review of the unsolvable task in dog communication and cognition: comparing different methodologies

Not the presence but the timing of acoustic signals influence dogs' behaviour toward an artificial agent

Some features of communicative signals may only direct the attention of the receiver to the signaller, and others may convey specific aspects of the message. Dogs rapidly engage in complex interactions with artificial agents allowing to test whether auditory cues of these agents can only serve as attention-getting cues or they can also convey context-specific message. Dogs encountered the agent first when it helped them to obtain an unreachable reward (Problem-solving); the agent was either (a) silent, or it emitted sound (b) at specific time intervals (Incongruent), or (c) congruently with its interactive behaviours (Congruent). Then, dogs could obtain a reward by following the agent's indication between two hiding places (Two-way choice). Dogs in all groups displayed communicative behaviour toward the agent. However, the Congruent group started to gaze at the agent later at the beginning of the Problem-solving, and their choice was at chance level in the Two-way choice. No difference was found between the Silent and Incongruent groups. Thus, not the attention-getting aspect of the sound, but the temporal synchronicity of the sound and specific behaviour influenced dogs' behaviour.

Body Awareness Does Not Need a Pedigree: Mixed-Breed Dogs Rely More on Self-Representation Than Social Learning in a Spatial Task

Body awareness allows the individual to negotiate spatial tasks by referencing their own body. Here, we tested whether biologically meaningful factors, such as an alternative solution (detour around an obstacle) and learning from a human demonstrator, would affect dogs' reliance on their body size in an aperture test. We hypothesized that the dogs would choose the socially reinforced solution over a shortcut, and they would choose the shortcut when the opening was comfortably large. We tested N = 45 adult, mixed-breed dogs, by using a 3 m long, transparent fence. The dogs had three trials with closed doors and then three trials with either a small (but passable) or a large open door. In the demonstration group the experimenter performed a detour before the first three trials, then we opened the large door. The dogs preferred the shortcut, where they relied on body awareness, as they either hesitated or opted for a detour when the small door was open. The dogs who watched the demonstration for longer in trial 3 chose the door less often in trial 4, which indicates social learning. By testing mixed-breed dogs, our results are minimally influenced by functional breed selection and serve as valuable baseline for testing complex socio-cognitive traits in companion dogs.

Evidence for the communicative function of human-directed gazing in 6- to 7-week-old dog puppies

In human infants, the ability to show gaze alternations between an object of interest and another individual is considered fundamental to the development of complex social-cognitive abilities. Here we show that well-socialised dog puppies show gaze alternations in two contexts at an early age, 6-7 weeks. Thus, 69.4% of puppies in a novel object test and 45.59% of puppies during an unsolvable task alternated their gaze at least once between a person's face and the object. In both contexts, the frequency of gaze alternations was positively correlated with the duration of whimpering, supporting the communicative nature of puppies' gazing. Furthermore, the number of gaze alternations in the two contexts was correlated, indicating an underlying propensity for gazing at humans despite likely different motivations in the two contexts. Similar to humans, and unlike great apes or wolves, domestic dogs show gaze alternations from an early age if they are well-socialised. They appear to have a genetic preparedness to communicate with humans via gaze alternations early in ontogeny, but they may need close contact with humans for this ability to emerge, highlighting the interactive effects of domestication and environmental factors on behavioural development in dogs.

Cooperative but Dependent-Functional Breed Selection in Dogs Influences Human-Directed Gazing in a Difficult Object-Manipulation Task

It is still largely unknown to what extent domestication, ancestry, or recent functional selection are responsible for the behavioral differences in whether dogs look back to a human when presented with a difficult task. Here, we tested whether this ubiquitous human-related response of companion dogs would appear differently in subjects that were selected for either cooperative or independent work tasks. We tested N = 71 dogs from 18 cooperative and 18 independent breeds. Subjects learned in a five-trial warming-up phase that they could easily obtain the reward from a container. In trial six, the reward became impossible to take out from the locked container. When the task was easy, both breed groups behaved similarly, and their readiness to approach the container did not differ between the last 'solvable' and the subsequent 'unsolvable' trial. Task focus, looking at the container, touching the container for the first time, or interacting with the container with a paw or nose did not differ between the breed groups, indicating that their persistence in problem solving was similar. However, in the 'unsolvable' trial, cooperative dogs alternated their gaze more often between the container and the humans than the independent dogs did. The frequency of looking back was also higher in cooperative dogs than in the independent breeds. These are the first empirical results that suggest, in a balanced, representative sample of breeds, that the selection for different levels of cooperativity in working dogs could also affect their human-dependent behavior in a generic problem-solving situation.

The good, the bad, the comfortable: a review of welfare practices and indicators based on the five domains model in farmed deer

Increasing consumer interest in game meat has globally expanded wild animal farming, with deer being a prominent non-traditional species farmed in numerous countries. Consequently, methods for assessing the welfare of captive animals have been developed over the last few decades, and despite its limitations, the Five Domains Model has become one of the most popular practical tools for welfare assessment. Our review focuses on welfare indicators in farmed red and fallow deer, the primary deer species in European farms. Among 57 studies, the majority emphasized deer health and nutrition, neglecting aspects like behavior and mental state. Notably, a significant portion explored human-animal interactions, especially in deer transportation. Summarizing literature for each domain, we propose reliable physical, behavioral, and physiological welfare indicators for farmed red and fallow deer. This comprehensive approach addresses current research gaps and contributes to enhancing the overall well-being of farmed deer.

Dogs understand the role of a human partner in a cooperative task

Humans are exceptionally flexible in cooperation, partly due to our ability to recognize the roles of cooperative partners. While some non-human animals understand the need for a partner in such interactions, it is unclear whether they grasp the consequences of their partner's actions and adjust accordingly. Previous studies utilizing economic games with non-human animals yielded mixed results. We investigated dogs, known for their close cooperation with humans, in a stag hunt game. Dogs could cooperate for better rewards or defect for lower ones, while their human partners would either cooperate, never cooperate, or act randomly. We control for attraction to food, side bias, and local enhancement. Dogs were more likely to coordinate with their partners when it led to better rewards, suggesting that they understood their partner's actions. By highlighting this cognitive skill in dogs, we advance our knowledge of the intricate mechanisms driving cooperative behavior in non-human animals.

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.

Modulation of dog-owner relationship and dog social and cognitive behavior by owner temperament and dog breed group

As companion dogs spend most of their lives with humans, the human-dog relationship and owner temperament may affect the dog behavior. In this study (n = 440), we investigated the relationship between the dog owner temperament (ATQ-R), owner-perceived dog-owner relationship (MDORS) and the dog behavior in three behavioral tests: the object-choice test, the unsolvable task, and the cylinder test. Dog owner temperament influenced the dog-owner relationship. Owners with high negative affectivity showed higher emotional closeness and perceived costs of their dog, whereas owners with high effortful control showed lower emotional closeness and perceived costs. Higher dog activity during the behavioral tests was also connected with owner-perceived lower emotional closeness. Furthermore, dog breed group modulated the connection between the owner temperament and dog behavior. Owner's high negative affectivity correlated with herding dogs' lower scores in the object choice test, while the behavior of primitive type dogs was unaffected by the owner temperament. Our results confirm that human characteristics are associated with the owner-reported dog-owner relationship, and owner temperament may have a modulatory effect on the dog social and cognitive behavior depending on the dog breed group, which should be investigated further.

Influence of reward and location on dogs' behaviour toward an interactive artificial agent

Animal-robot interaction studies provide outstanding opportunities to understand the principles of social interactions. Here we investigated whether dogs' behaviour toward a cooperative artificial agent (Unidentified Moving Object (UMO)) is influenced by receiving a reward directly from the agent, and by variability in the UMO's location. In a problem-solving task, the UMO either helped dogs to obtain food (Direct Reward Group, DRG) or to fetch an object followed by an indirect reward from the owner/experimenter (Indirect Reward Group, IRG). During the Familiarization, the UMO either started from the same location or changed its starting location in all trials. In the Test phase, dogs faced the same task, but additionally a second, unfamiliar UMO was present. We found that both reward groups gazed at the UMO with decreasing latency during the Familiarization, with the IRG showing more gaze alternations between UMO and hiding location. Dogs showed no preference for either UMO in the Test phase but looked at the familiar UMO sooner if it had changed its location during the Familiarization. Thus, direct reward is not necessary to elicit elements of socially competent behavior in dogs, but variability in its motion may be important to improve the UMO's animacy and promote flexible learning.

Relationship between engagement with the impossible task, cognitive testing, and cognitive questionnaires in a population of aging dogs

Introduction

The aim of this study was to evaluate the engagement of aging dogs with a cognitively challenging and potentially frustrating task (the impossible task). Based on previous observations, we predicted that dogs showing signs of cognitive impairment in other cognitive tests and owner-completed questionnaires would show reduced engagement with the task.

Methods

In this task, dogs were shown a piece of food in a clear container that they could not open; time spent interacting with the container and the experimenter was measured. While the impossible task has not been used as a measure of frustration, the parameters of the test design creates a potential frustrate state, making this assessment appropriate. Thirty-two dogs enrolled in a longitudinal aging study participated in the study. Owners were asked to complete two cognitive dysfunction screening questionnaires (Canine Dementia Scale [CADES] and Canine Cognitive Dysfunction Rating Scale [CCDR]) as well a questionnaire assessing general frustration. Dogs participated in multiple measures of cognitive function as well the impossible task.

Results

Latency to disengage from the impossible task was faster for dogs with higher total (more impaired) CADES (p = 0.02) and total CCDR (p = 0.04) scores. Latency to disengage also correlated with decreased performance in cognitive tests observing social cues (p = 0.01), working memory (p ≤ 0.001), spatial reasoning and reversal learning (p = 0.02), and sustained attention (p = 0.02).

Discussion

The high correlation with several cognitive measures and the ease of administration of this test makes it a useful tool in evaluating canine cognitive dysfunction syndrome, however it is unclear if increased frustration or other cognitive processes are contributing to the observed changes.

Breed differences in social cognition, inhibitory control, and spatial problem-solving ability in the domestic dog (Canis familiaris)

The extraordinary genetic and behavioural diversity of dog breeds provides a unique opportunity for investigating the heritability of cognitive traits, such as problem-solving ability, social cognition, inhibitory control, and memory. Previous studies have mainly investigated cognitive differences between breed groups, and information on individual dog breeds is scarce. As a result, findings are often contradictory and inconsistent. The aim of this study was to provide more clarity on between-breed differences of cognitive traits in dogs. We examined the performance of 13 dog breeds (N = 1002 dogs) in a standardized test battery. Significant breed differences were found for understanding of human communicative gestures, following a human's misleading gesture, spatial problem-solving ability in a V-detour task, inhibitory control in a cylinder test, and persistence and human-directed behaviour during an unsolvable task. Breeds also differed significantly in their behaviour towards an unfamiliar person, activity level, and exploration of a novel environment. No significant differences were identified in tasks measuring memory or logical reasoning. Breed differences thus emerged mainly in tasks measuring social cognition, problem-solving, and inhibitory control. Our results suggest that these traits may have come under diversifying artificial selection in different breeds. These results provide a deeper understanding on breed-specific traits in dogs.

Disentangling help-seeking and giving up: differential human-directed gazing by dogs in a modified unsolvable task paradigm

Dogs are renowned for 'looking back' at humans when confronted with a problem, but it has been questioned whether this implies help-seeking or giving up. We tested 56 pet dogs from two breed groups (herding dogs and terriers) in a modified unsolvable task paradigm. One reward type (food or toy) was enclosed in a box, while the respective other reward was accessible. With both reward types, human-directed gazing in relation to the box was significantly positively correlated with interaction with the box, as long as an alternative was available. This suggests that both behaviours served to attain the unavailable reward and reflected individual motivation for the inaccessible vs the accessible reward. Furthermore, we varied whether the owner or the experimenter was responsible for handling the rewards. In the owner-responsible group, dogs rarely gazed at the experimenter. In the experimenter-responsible group, dogs preferentially directed box-related gazing (prior to or after looking at or interacting with the box) at the owner. Still, they gazed at the experimenter significantly longer than the owner-responsible group. Conversely, toy-related gazing was directed significantly more at the experimenter. Thus, dogs adjust their gazing behaviour according to the people's responsibility and their current goal (help-seeking vs play). Gaze duration did not differ between herding dogs and terriers. We conclude that dogs use gazing at humans' faces as a social problem-solving strategy, but not all gazing can be classified as such. Dogs' human-directed gazing is influenced by the social relationships with the persons, situational associations, and context (unsolvable problem vs play).

Persistence and gazing at humans during an unsolvable task in dogs: The influence of ownership duration, living situation, and prior experience with humans

The experiences that domestic dogs have with humans take many forms. We hypothesized that more experience with humans would lead to greater dependence on humans in problem-solving situations. We used the unsolvable task to compare persistence and gazing in dogs with differing degrees of experience with humans: 1) dogs living in a home for a year or more; 2) dogs living in a home for less than a year (including foster dogs); and 3) shelter dogs. Dogs first learned a solvable task; we then measured persistence as well as gazing at humans when the task was unsolvable. Dogs living in a home for a year or more gazed sooner and longer than shelter dogs. Formally trained dogs from breeders also gazed sooner than formally trained dogs from shelters. There were no differences in overall persistence among the three types of dog. However, shelter dogs spent more time biting the box and gazing at it than dogs in the home. Former shelter dogs, former strays, and dogs that had no formal training also spent more time biting the box. We conclude that ownership duration, background, and prior experiences with humans influence human-directed communication and persistence behaviors in dogs.

Serum Oxytocin in Cows Is Positively Correlated with Caregiver Interactions in the Impossible Task Paradigm

Simple Summary

A possible relationship between circulating hormones (e.g., oxytocin and cortisol) and social behaviors toward humans in cows was studied using the impossible task paradigm test. Serum oxytocin levels correlated positively with the duration and negatively correlated with the latency of the cows’ social interactions with the caregiver. The implications of these findings for productivity as well as for animal welfare can be numerous and worth further investigation.

Abstract

This study explored a possible relationship between the circulating oxytocin, cortisol, and the willingness of dairy cows to engage in social behaviors with humans in an experimental context. The behaviors of twenty-nine cows were recorded during the impossible task paradigm, a procedure aimed at creating a violation of expectancy, in the presence of the caregiver and a stranger. The results showed that serum oxytocin levels were positively correlated with duration and negatively correlated with the latency of the cows’ social interactions with the caregiver. This research provides a clear correlation between circulating oxytocin and a willingness to engage in social contact with the caregiver, excluding the possible effect of different cortisol levels on such behavior.

Breed group differences in the unsolvable problem task: herding dogs prefer their owner, while solitary hunting dogs seek stranger proximity

The communicating skills of dogs are well documented and especially their contact-seeking behaviours towards humans. The aim of this study was to use the unsolvable problem paradigm to investigate differences between breed groups in their contact-seeking behaviours towards their owner and a stranger. Twenty-four dogs of ancient breeds, 58 herding dogs, and 17 solitary hunting dogs were included in the study, and their behaviour when presented with an unsolvable problem task (UPT) was recorded for 3 min. All breed groups interacted with the test apparatus the same amount of time, but the herding dogs showed a longer gaze duration towards their owner compared to the other groups and they also preferred to interact with their owner instead of a stranger. Interestingly, the solitary hunting dogs were more in stranger proximity than the other groups, and they also showed a preference to make contact with a stranger instead of their owner. Hence, we found differences in contact-seeking behaviours, reflecting the dog–human relationship, between breed groups that might not only be related to their genetic similarity to wolves, but also due to the specific breeding history of the dogs.

A comparative test of inequity aversion in domestic dogs (Canis familiaris) and dingoes (Canis dingo)

Despite much recent empirical work on inequity aversion in nonhuman species, many questions remain about its distribution across taxa and the factors that shape its evolution and expression. Past work suggests that domestic dogs (Canis familiaris) and wolves (Canis lupus) are averse to inequitable resource distributions in contexts that call upon some degree of training such as 'give paw' and 'buzzer press' tasks. However, it is unclear whether inequity aversion appears in other canid species and in other experimental contexts. Using a novel inequity aversion task that does not require specific training, this study helps address these gaps by investigating inequity aversion in domestic dogs and a closely related but non-domesticated canid, the dingo (Canis dingo). Subjects were presented with equal and unequal reward distributions and given the opportunity to approach or refuse to approach allocations. Measures of interest were (1) subjects' refusal to approach when getting no food; (2) approach latency; and (3) social referencing. None of these measures differed systematically across the inequity condition and control conditions in either dogs or dingoes. These findings add to the growing literature on inequity aversion in canids, providing data from a new species and a new experimental context. Additionally, they raise questions about the experimental features that must be in place for inequity aversion to appear in canids.

Effect of different experiences with humans in dogs' visual communication

Dogs are particularly skillful in communicating with humans, and growing evidence points towards the importance of both species intertwined evolutionary history and intense daily partnership. Gaze alternation is a communicative behavior used by dogs from a very young age and is affected by factors such as aging and experience. We analyzed how different degrees of daily human interaction affect dogs' gazing behavior in the unsolvable task, where a desired food becomes inaccessible. Three groups with different degrees of daily exposure to humans were compared: pet dogs that live inside the house, pet dogs that live outside the house, and shelter dogs. We found no difference in latency to the first gaze, but pet dogs did show a higher proportion of individuals engaging in gaze alternation, a higher number of gaze alternations, and a longer duration of gaze than shelter dogs. Additionally, dogs living inside the house gazed more at the experimenter than dogs living outside. Overall, our results indicate a strong influence of experience over the development and use of these communicative behaviors in dogs, with groups that are closer to people in their daily lives being more willing to communicate with humans as a strategy to obtain a desired goal.

Effect of Sex and Reproductive Status on Inhibitory Control and Social Cognition in the Domestic Dog (Canis familiaris)

Simple Summary

Various behavioral differences exist between male and female dogs, but very little research has focused on how sex influences cognition. Even fewer studies have taken sex hormones into account. Our aim was to investigate whether dogs’ sex and neutering status can influence two important cognitive traits: inhibitory control and social cognition. Inhibitory control was assessed using the cylinder test. In this task, the dog is required to inhibit reaching for a treat directly through a transparent barrier, and instead go around the barrier to access the treat. Social cognition was assessed using the unsolvable task, during which a food reward is visible but impossible to access. Dogs have three opportunities for action in this situation: (a) persisting with the problem independently, (b) seeking attention from a human, or (c) abandoning the task. Males were more impulsive and independent compared to females, whereas females had greater inhibitory control and were more likely to gaze at a human during a problem-solving situation. Since neutering status did not affect the results, it seems likely that these sex differences arose during early development and were not affected by levels of circulating sex hormones to a great extent.

Abstract

Sex differences in a variety of cognitive traits have long been reported in various species, including dogs. However, only a few canine studies have taken the possible effect of reproductive hormones into account. The aim of this study was to investigate the effects of sex and reproductive status of pet dogs (N = 1032) on two cognitive traits: inhibitory control and social cognition. Inhibitory control was assessed using the cylinder test, and the dogs’ tendency to initiate social contact with a human during a problem-solving situation was assessed using the unsolvable task. Female dogs had a significantly higher success rate in the cylinder test compared to males, and they spent significantly more time in human-directed behavior during the unsolvable task. In contrast, males spent significantly more time in independent behavior during the unsolvable task. Reproductive status had no significant effect on the results of the cylinder test or the unsolvable task. Our results showed that female dogs asked for more help/used a more cooperative strategy during a problem-solving situation and had greater inhibitory control compared to males. According to our results, it seems likely that these sex differences were not influenced to a large extent by reproductive hormones.