Perception of optical illusions in ungulates: insights from goats, sheep, guanacos and llamas.

Optical illusions have long been used in behavioural studies to investigate the perceptual mechanisms underlying vision in animals. So far, three studies have focused on ungulates, providing evidence that they may be susceptible to some optical illusions, in a way similar to humans. Here, we used two food-choice tasks to study susceptibility to the Müller-Lyer and Delboeuf illusions in 17 captive individuals belonging to four ungulate species (Lama guanicoe, Lama glama, Ovis aries, Capra hircus). At the group level, there was a significant preference for the longer/larger food over the shorter/smaller one in control trials. Additionally, the whole group significantly preferred the food stick between two inward arrowheads over an identical one between two outward arrowheads in experimental trials of the Müller-Lyer task, and also preferred the food on the smaller circle over an identical one on the larger circle in the experimental trials of the Delboeuf task. Group-level analyses further showed no significant differences across species, although at the individual level we found significant variation in performance. Our findings suggest that, in line with our predictions, ungulates are overall susceptible to the Müller-Lyer and the Delboeuf illusions, and indicate that the perceptual mechanisms underlying size estimation in artiodactyls might be similar to those of other species, including humans.

Intra and interspecific audience effect on domestic dogs' behavioural displays and facial expressions.

The aim of the current study was to investigate the influence of both intra- and interspecific audiences on dogs' facial expressions and behaviours. Forty-six dogs were exposed to three test conditions in which a food reward, initially available, was denied when in the presence of either a human (Human condition) or a dog audience (Dog condition), or in the absence of a visible audience (Non-social condition). Salivary cortisol was collected to evaluate the stress/arousal activation in the different conditions. Compared to the Non-social condition, the presence of a conspecific evoked more facial expressions, according to the DogFACS (Facial Action Coding System, an anatomically based tool to analyze facial expressions in domestic dogs), (EAD105-Ears downward), displacement behaviours (AD137-Nose licking, AD37-Lip wiping), tail wagging, whining, and panting (AD126). When facing a conspecific, dogs assumed a more avoidant attitude, keeping a distance and not looking at the stimuli, compared to when in the presence of the human partner. Dogs also exhibited more facial expressions (EAD102-Ears Adductor, EAD104-Ears Rotator), displacement behaviours (AD137-Nose licking, AD37-Lip wiping), panting (AD126) and whining when facing the conspecific than the human partner. Post-test cortisol was not influenced by any condition, and no association between pre-test cortisol and behavioural variables was found, thus strong differences in the levels of stress/arousal were unlikely to be responsible for differences in behavior between conditions. Considering the current results in the context of the available literature, we suggest that the higher displacement behaviors exhibited with the conspecifics were likely due to an increased level of uncertainty regarding the situations.

Environmental enrichments and data-driven welfare indicators for sheltered dogs using telemetric physiological measures and signal processing.

Shelters are stressful environments for domestic dogs which are known to negatively impact their welfare. The introduction of outside stimuli for dogs in this environment can improve their welfare and life conditions. However, our current understanding of the influence of different stimuli on shelter dogs' welfare is limited and the data is still insufficient to draw conclusions. In this study, we collected 28 days (four weeks) of telemetry data from eight male dogs housed in an Italian shelter for a long period of time. During this period, three types of enrichment were introduced into the dogs' pens for one week each: entertaining objects, intraspecific, and interspecific social enrichment, by means of the presence of female conspecifics and the presence of a human. To quantify their impact, we introduce novel metrics as indicators of sheltered dogs' welfare based on telemetry data: the variation of heart rate, muscle activity, and body temperature from an average baseline day, quality of sleep, and the regularity for cyclicity of the aforementioned parameters, based on the day-night cycle. Using these metrics, we show that while all three stimuli statistically improve the dogs' welfare, the variance between individual dogs is large. Moreover, our findings indicate that the presence of female conspecific is the best stimulus among the three explored options which improves both the quality of sleep and the parameters' cyclicity. Our results are consistent with previous research findings while providing novel data-driven welfare indicators that promote objectivity. Thus, this research provides some useful guidelines for managing shelters and improving dogs' welfare.

Appeasement function of displacement behaviours? Dogs' behavioural displays exhibited towards threatening and neutral humans.

Appeasement signals are behavioural patterns displaying an animal's non-aggressive attitude and are hypothesized to reduce the aggressive behaviours in the receiver. In domestic dogs, specific displacement behaviours (i.e., behavioural patterns exhibited without an apparent function related to the ongoing situation), have been suggested to function as appeasement signals. To test this possibility, we assessed whether the occurrence of these behaviours was dependent on a social conflict context, predicting that, if displacement behaviours also function as appeasement signals, they should be more prevalent in a conflict vs. non-conflict context. Fifty-three dogs were exposed to two unfamiliar humans approaching them in either a mildly threatening or neutral way. We categorized the attitude of the dogs towards the strangers as "reactive", i.e., barking and lunging towards the stimulus, and "non-reactive", i.e., remaining passive in front of the stimuli. We coded dogs' displacement activities and modelled their duration or frequency as a function of the interaction between the test condition and the attitude of the dog. Displacement behaviours of "blinking", "nose licking" and "lip wiping" were associated with a "non-reactive" attitude, independently from the test condition, confirming an association with a non-aggressive intention. "Head turning" was associated with a "non-reactive" attitude in the threatening condition. In conclusion, dogs with a non-aggressive attitude exhibited more putative appeasement signals; however, these were not strictly associated with a conflict-ridden situation, calling for further investigation of their function.

When the owner does not know: comparing puppies and adult dogs' showing behavior.

Domestic dogs have been shown to engage in interspecific communication with their owners using a flexible repertoire of signals (i.e., gaze, vocalizations, and postures). This ability is influenced by ontogenetic development as well as breed selection. Different aspects of this phenomenon have been studied using the out of reach/hidden object task in which a piece of food is shown to the dog and then hidden in an unreachable spot by the experimenter. Dogs' behavioral displays toward the target and the owner (ignorant about the location of the food) have been observed. The complex communicative behavior dogs exhibit in this context is defined as showing behavior and includes attention-getting components directed toward the owner, and directional components directed toward the target. No study has investigated the ontogenetic development of this behavior. In the current study, we compared the showing behavior in 4-6 month old puppies and 2-11 year old adults in an out of reach task involving the hiding of a food reward in one of two cabinets. Dogs were exposed to three conditions: (1) Owner with Food (OF), (2) Owner No Food (ONF), and (3) Alone with food (AF). Dogs showed more gaze alternations when both the food and the owner were present confirming the intentional and referential nature of this behavior. Contrary to our expectations, we found no differences between the showing behaviors of 4-6 month old puppies and adult dogs. This study provides interesting preliminary evidence of showing behavior in puppies. Further studies are needed to gain a deeper understanding of the factors influencing this communicative behavior (i.e., breed, level of training). Furthermore, longitudinal studies should be performed from the age of 2 months up to 1 and 2 years to better clarify the influence of development and experience on showing behavior in domestic dogs.

Audience effect on domestic dogs' behavioural displays and facial expressions.

In the present study we investigated the influence of positive and negative arousal situations and the presence of an audience on dogs' behavioural displays and facial expressions. We exposed dogs to positive anticipation, non-social frustration and social frustration evoking test sessions and measured pre and post-test salivary cortisol concentrations. Cortisol concentration did not increase during the tests and there was no difference in pre or post-test concentrations in the different test conditions, excluding a different level of arousal. Displacement behaviours of "looking away" and "sniffing the environment" occurred more in the frustration-evoking situations compared to the positive anticipation and were correlated with cortisol concentrations. "Ears forward" occurred more in the positive anticipation condition compared to the frustration-evoking conditions, was positively influenced by the presence of an audience, and negatively correlated to the pre-test cortisol concentrations, suggesting it may be a good indicator of dogs' level of attention. "Ears flattener", "blink", "nose lick", "tail wagging" and "whining" were associated with the presence of an audience but were not correlated to cortisol concentrations, suggesting a communicative component of these visual displays. These findings are a first step to systematically test which subtle cues could be considered communicative signals in domestic dogs.

Group Reunion in Zoo European Wildcats Using Cat Appeasing Pheromone (CAP) and Gradual Release of the Animals in the Exhibit-A Case Study.

The union or reunion of animals with social groups can be a challenging situation, and little has been published about it when solitary species are concerned. Therefore, the aim of the present study was two-fold: (1) to advocate the need for systematic publications about strategies and the outcomes of reunion episodes in zoos and other facilities; and (2) to describe the behaviour of European wildcats (Felis silvestris silvestris) during one such episode, in which a female cat was reintroduced into her family social group using a gradual reunion procedure and cat appeasing pheromone (CAP) (spot-on). The study comprised three periods: the pre-reunion period (10 days, 20 sessions per wildcat), the post-reunion period (A, 5 days, 10 sessions per wildcat; B, 5 days, 10 sessions per wildcat) and the late-reunion period (5 days, 10 sessions per wildcat). In the post-reunion periods, all wildcats were together in the enclosure and were spotted with CAP pheromone. Per period, we collected data on individual and social behaviours. Individual behaviours, such as attention and self-grooming, were performed more in the pre-reunion than in the post-reunion period. Regarding social behaviours, we found that agonistic behaviours were performed more in the pre-reunion than in the post-reunion period. We observed behavioural changes over the course of the study, with behavioural patterns of the late-reunion periods resembling those of the pre-reunion period.

A promising novel judgement bias test to evaluate affective states in dogs (Canis familiaris).

The judgement bias test represents one of the most applied tools to evaluate animals' optimistic/pessimistic attitude and to infer their emotional and welfare state accordingly. The judgement bias test (JBT) has been used several times with dogs (Canis familiaris), in most cases using a spatial test that evaluates the dog's attitude towards a bowl placed in ambiguous positions (located between two unambiguous trained positions associated with opposite outcomes). Results are contrasting and methodological and statistical caveats emerged: dogs struggled to learn the association between unambiguous positions and their outcomes, they hardly discriminated between adjacent locations and they might be influenced by researchers. Therefore, we propose a novel paradigm, aimed at easing the learning process and at achieving more reliable measures. Improvements of the novel paradigm are the increased difference between payoffs of trained locations, the reduction of the number of trials and of their length and the removal of the potential influence of researchers. Results showed that 98% of dogs reached the learning criterion and that their learning appeared more stable: dogs behaved differently between the two trained stimuli and the variability of responses towards these stimuli was lower than the one towards ambiguous stimuli. Behavioural analyses confirmed that dogs fully learned outcomes associated with trained stimuli and that they were hesitant towards ambiguous stimuli. Furthermore, dogs managed to successfully discriminate between each pair of adjacent locations. These results suggest that this protocol is a promising tool to assess judgement biases in dogs and to evaluate their affective state.

Infrared Thermography in the Study of Animals' Emotional Responses: A Critical Review.

Whether animals have emotions was historically a long-lasting question but, today, nobody disputes that they do. However, how to assess them and how to guarantee animals their welfare have become important research topics in the last 20 years. Infrared thermography (IRT) is a method to record the electromagnetic radiation emitted by bodies. It can indirectly assess sympathetic and parasympathetic activity via the modification of temperature of different body areas, caused by different phenomena such as stress-induced hyperthermia or variation in blood flow. Compared to other emotional activation assessment methods, IRT has the advantage of being noninvasive, allowing use without the risk of influencing animals' behavior or physiological responses. This review describes general principles of IRT functioning, as well as its applications in studies regarding emotional reactions of domestic animals, with a brief section dedicated to the experiments on wildlife; it analyzes potentialities and possible flaws, confronting the results obtained in different taxa, and discusses further opportunities for IRT in studies about animal emotions.

Using judgment bias test in pet and shelter dogs (Canis familiaris): Methodological and statistical caveats.

It is now widely agreed that a positive affective state is a crucial component of animal well-being. The judgment bias test represents a widespread tool used to assess animals' optimistic/pessimistic attitude and to evaluate their emotional state and welfare. Judgment bias tests have been used several times with dogs (Canis familiaris), in most cases using a spatial test with a bowl placed in ambiguous positions located between a relatively positive trained location (P) which contains a baited bowl and a relatively negative trained location (N) which contains an empty bowl. The latency to approach the bowl in the ambiguous locations is an indicator of the dog's expectation of a positive/negative outcome. However, results from such tests are often inconclusive. For the present study, the judgment bias test performance of 51 shelter dogs and 40 pet dogs was thoroughly analysed. A pattern emerged with shelter dogs behaving in a more pessimistic-like way than pet dogs. However, this difference between the two populations was detected only when analysing the raw latencies to reach the locations and not the more commonly applied adjusted score (i.e. average latency values). Furthermore, several methodological caveats were found. First of all, a non-negligible percentage of dogs did not pass the training phase, possibly due to the experimental paradigm not being fully suited for this species. Second, results showed a high intra-dog variability in response to the trained locations, i.e. the dogs' responses were not consistent throughout the test, suggesting that animals may not have fully learned the association between locations and their outcomes. Third, dogs did not always behave differently towards adjacent locations, raising doubts about the animals' ability to discriminate between locations. Finally, a potential influence of the researcher's presence on dogs' performance emerged from analyses. The implications of these findings and potential solutions are discussed.

Revisiting a Previously Validated Temperament Test in Shelter Dogs, Including an Examination of the Use of Fake Model Dogs to Assess Conspecific Sociability.

This study assessed the feasibility and reproducibility of a previously validated temperament test (TT) for shelter dogs. The test was developed to measure dog behaviour in the kennel, and traits of sociability towards people and other dogs, docility to leash, playfulness, cognitive skills, and reactivity. We introduced the use of differently sized fake dogs to check their appropriateness in correctly assessing sociability to dogs to broaden its applicability (as the original study used real stimulus dogs). We hypothesised that dogs' responses may be modulated by the body size of the stimulus dog presented. The reduction analysis of the TT scores extracted five main dimensions (explaining 70.8% of variance), with high internal consistency (alpha > 0.65) and being broadly consistent with existing research. Behavioural components that were extracted from the fake dog experiment showed that dogs are likely to show signs of anxiety and fear toward both the real and fake dog. Dogs' responses towards a real vs. fake stimulus were significantly correlated (p < 0.05) and they were not affected by the size of the stimulus (p > 0.05). We discuss the importance of interpreting these data with caution and use behavioural tests as a partial screening tool to be used in conjunction with more extensive behavioural and welfare monitoring.

Effects of breed group and development on dogs' willingness to follow a human misleading advice.

The aim of this work was to investigate the effect of dog breed groups, i.e., primitive, hunting/herding and Mastiff like (Study 1) and development, i.e., 4-month-old puppies vs adults (Study 2) on a quantity discrimination task. The task consisted of three conditions: C1-dogs were asked to choose between a large and a small amount of food; C2-the same choice was presented and dogs could choose after having witnessed the experimenter favouring the small quantity. C3-similar to C2 but the plates had two equally small food quantities. Study 1 revealed that dogs in the hunting/herding group were significantly more likely than Mastiff-like group to choose the small quantity indicated by the person over the large one, although all dog groups chose the large quantity over the small when they had a free choice. These results are consistent with the hypothesis that hunting/herding breeds have been selected for working in cooperation with humans and thus may be more sensitive to human social communicative cues than other breeds. In Study 2, results showed that 4-month-old puppies performed at chance level in C1, whereas in C2 both adults and puppies conformed to the experimenter's choice. In C3, adults followed the experimenter significantly more than puppies, although puppies still followed the experimenter above chance. Overall, domestic dogs seem to rely heavily on social communicative cues from humans, even when the information contradicts their own perception. This tendency to respond to human social cues is present, although at a lesser extent already at 4 months.

Pet dogs' behavior when the owner and an unfamiliar person attend to a faux rival.

While dog owners ascribe different emotions to their pets, including jealousy, research on secondary emotions in nonhuman animals is very limited and, so far, only one study has investigated jealousy in dogs (Canis familiaris). This work explores jealousy in dogs one step further. We conducted two studies adapting a procedure devised to assess jealousy in human infants. In each study 36 adult dogs were exposed to a situation in which their owner and a stranger ignored them while directing positive attention towards three different objects: a book, a puppet and a fake dog (Study 1: furry; Study 2: plastic). Overall, the results of both studies do not provide evidence that the behavioral responses of our dogs were triggered by jealousy: we did not find a clear indication that the fake dogs were perceived as real social rivals, neither the furry nor the plastic one. Indeed, dogs exhibited a higher interest (i.e. look at, interact with) towards the fake dogs, but differences in the behavior towards the fake dog and the puppet only emerged in Study 2. In addition, many of the behaviors (protest, stress, attention seeking, aggression) that are considered distinctive features of jealousy were not expressed or were expressed to a limited extent, revealing that dogs did not actively try to regain their owner's attention or interfere with the interaction between the owner and the faux rival. Finally, a differentiated response towards the attachment figure (the owner) and the unfamiliar person (the stranger) did not emerge. Differently from what reported in human infants, dogs' behavior towards the attachment figure and the stranger interacting with the potential competitor (in this case, the fake dog) did not significantly differ: in both studies dogs paid attention to the owner and the stranger manipulating the fake dog to the same extent. In conclusion, we do not exclude that dogs could possess a rudimentary form of jealousy, but we suggest that research on this topic should require the use of a real social interloper (conspecific or human) and more naturalistic procedures.

Breed, sex, and litter effects in 2-month old puppies' behaviour in a standardised open-field test.

A considerable number of studies have reported differences among dog breeds with respect to their genetic profile, cognitive abilities or personality traits. Each dog breed is normally treated as a homogeneous group, however, researchers have recently questioned whether the behavioural profile of modern breeds still reflects their historical function or if the intense divergent selective pressures and geographical barriers have created a more fragmented picture. The majority of studies attempting to assess and compare modern breeds' personality focused on the evaluation of adult dogs where the potential effects of environmental/human factors on the dogs' behaviour are hard to discern from their genetic heritage. In the following study, we aimed at investigating between- and within-breed differences in the personality of two-months-old puppies by direct behavioural observation of 377 puppies from 12 breeds. Results showed that there was no effect of sex, however both breed and litter, significantly affected all personality traits. Breed on average explained 10% of the variance, whereas the effect of litter was noticeably higher, explaining on average 23% of the variance. Taken together, our results suggest that breed does have some influence on personality traits, but they also highlight the importance of taking litter effects into account.

The importance of gestural communication: a study of human-dog communication using incongruent information.

We assessed how water rescue dogs, which were equally accustomed to respond to gestural and verbal requests, weighted gestural versus verbal information when asked by their owner to perform an action. Dogs were asked to perform four different actions ("sit", "lie down", "stay", "come") providing them with a single source of information (in Phase 1, gestural, and in Phase 2, verbal) or with incongruent information (in Phase 3, gestural and verbal commands referred to two different actions). In Phases 1 and 2, we recorded the frequency of correct responses as 0 or 1, whereas in Phase 3, we computed a 'preference index' (percentage of gestural commands followed over the total commands responded). Results showed that dogs followed gestures significantly better than words when these two types of information were used separately. Females were more likely to respond to gestural than verbal commands and males responded to verbal commands significantly better than females. In the incongruent condition, when gestures and words simultaneously indicated two different actions, the dogs overall preferred to execute the action required by the gesture rather than that required verbally, except when the verbal command "come" was paired with the gestural command "stay" with the owner moving away from the dog. Our data suggest that in dogs accustomed to respond to both gestural and verbal requests, gestures are more salient than words. However, dogs' responses appeared to be dependent also on the contextual situation: dogs' motivation to maintain proximity with an owner who was moving away could have led them to make the more 'convenient' choices between the two incongruent instructions.

How good is this food? A study on dogs' emotional responses to a potentially pleasant event using infrared thermography.

Understanding how animals express positive emotions is becoming an interesting and promising area of research in the study of animal emotions and affective experiences. In the present study, we used infrared thermography in combination with behavioral measures, heart rate (HR) and heart rate variability (HRV), to investigate dogs' emotional responses to a potentially pleasant event: receiving palatable food from the owner. Nineteen adult pet dogs, 8 females and 11 males, were tested and their eye temperature, HR, HRV and behavior were recorded during a 30-minutestestconsisting of three 10-minute consecutive phases: Baseline (Phase 1), positive stimulation through the administration of palatable treats (Feeding, Phase 2) and Post-feeding condition following the positive stimulation (Phase 3). Dogs' eye temperature and mean HR significantly increased during the positive stimulation phase compared with both Baseline and Post-feeding phases. During the positive stimulation with food (Phase 2), dogs engaged in behaviors indicating a positive emotional state and a high arousal, being focused on food treats and increasing tail wagging. However, there was no evidence of an increase in HRV during Phase 2 compared to the Phase 1, with SDNN significantly increasing only in Phase 3, after the positive stimulation occurred. Overall results point out that IRT may be a useful tool in assessing emotional states in dogs in terms of arousal but fails to discriminate emotional valence, whose interpretation cannot disregard behavioral indexes.

Does Subjective Rating Reflect Behavioural Coding? Personality in 2 Month-Old Dog Puppies: An Open-Field Test and Adjective-Based Questionnaire.

A number of studies have recently investigated personality traits in non-human species, with the dog gaining popularity as a subject species for research in this area. Recent research has shown the consistency of personality traits across both context and time for adult dogs, both when using questionnaire based methods of investigation and behavioural analyses of the dogs' behaviour. However, only a few studies have assessed the correspondence between these two methods, with results varying considerably across studies. Furthermore, most studies have focused on adult dogs, despite the fact that an understanding of personality traits in young puppies may be important for research focusing on the genetic basis of personality traits. In the current study, we sought to evaluate the correspondence between a questionnaire based method and the in depth analyses of the behaviour of 2-month old puppies in an open-field test in which a number of both social and non-social stimuli were presented to the subjects. We further evaluated consistency of traits over time by re-testing a subset of puppies. The correspondence between methods was high and test- retest consistency (for the main trait) was also good using both evaluation methods. Results showed clear factors referring to the two main personality traits 'extroversion,' (i.e. the enthusiastic, exuberant approach to the stimuli) and 'neuroticism,' (i.e. the more cautious and fearful approach to the stimuli), potentially similar to the shyness-boldness dimension found in previous studies. Furthermore, both methods identified an 'amicability' dimension, expressing the positive interactions the pups directed at the humans stranger, and a 'reservedness' dimension which identified pups who largely chose not to interact with the stimuli, and were defined as quiet and not nosey in the questionnaire.

The effect of training and breed group on problem-solving behaviours in dogs.

Dogs have become the focus of cognitive studies looking at both their physical and social problem-solving abilities (Bensky et al. in Adv Stud Behav, 45:209-387, 2013), but very little is known about the environmental and inherited factors that may affect these abilities. In the current study, we presented a manipulation task (a puzzle box) and a spatial task (the detour) to 128 dogs belonging to four different breed groups: Herding, Mastiff-like, Working and Retrievers (von Holdt et al. in Nature 464:898-902, 2010). Within each group, we tested highly trained and non-trained dogs. Results showed that trained dogs were faster at obtaining the reward in the detour task. In the manipulation task, trained dogs approached the apparatus sooner in the first familiarization trial, but no effect of breed emerged on this variable. Furthermore, regardless of breed, dogs in the trained group spent proportionally more time interacting with the apparatus and were more likely to succeed in the test trial than dogs in the non-trained group, whereas regardless of training, dogs in the working breed group were more likely to succeed than dogs in the retriever and herding breed groups (but not the mastiff-like group). Finally, trained dogs were less likely to look at a person than non-trained dogs during testing, but dogs in the herding group more likely to do so than dogs in the retriever and working but not the mastiff-like breed groups. Overall, results reveal a strong influence of training experience but less consistent differences between breed groups on different components thought to affect problem solving.

Guide dogs as a model for investigating the effect of life experience and training on gazing behaviour.

The present study aimed at evaluating possible behavioural differences between guide dogs living in a kennel and interacting with a trainer and those living in a house and interacting with a blind person and their family, when they are faced with an unsolvable task. Fifty-two Labrador retrievers were tested: 13 Trained Guide dogs at the end of their training programme and 11 Working Guide dogs that had been living with their blind owner for at least 1 year. Two control groups of Labrador retrievers were also tested: 14 Young Untrained dogs of the same age as the Trained Guide and 14 Old Untrained dogs of the same age as the Working Guide dogs. Results showed that the Trained Guide dogs gazed towards the owner or the stranger for less time and with a higher latency and spent more time interacting with the experimental apparatus than the other three groups, which all behaved similarly. None of the groups tested showed preferences in gazing towards the stranger or the owner. Together, the results suggest that at the end of their training programme, guide dogs are less prone to engage in human-directed gazing behaviour and more likely to act independently when facing an unsolvable task. Conversely, guide dogs that have been living with a blind person (and their family) for 1 year behave like pet dogs. These findings indicate that guide dogs' gazing towards humans is favoured by living in close proximity with people and by interacting with them.

Gazing toward humans: a study on water rescue dogs using the impossible task paradigm.

Various studies have assessed the role of life experiences, including learning opportunities, living conditions and the quality of dog-human relationships, in the use of human cues and problem-solving ability. The current study investigates how and to what extent training affects the behaviour of dogs and the communication of dogs with humans by comparing dogs trained for a water rescue service and untrained pet dogs in the impossible task paradigm. Twenty-three certified water rescue dogs (the water rescue group) and 17 dogs with no training experience (the untrained group) were tested using a modified version of the impossible task described by Marshall-Pescini et al. in 2009. The results demonstrated that the water rescue dogs directed their first gaze significantly more often towards the owner and spent more time gazing toward two people compared to the untrained pet dogs. There was no difference between the dogs of the two groups as far as in the amount of time spent gazing at the owner or the stranger; neither in the interaction with the apparatus attempting to obtain food. The specific training regime, aimed at promoting cooperation during the performance of water rescue, could account for the longer gazing behaviour shown toward people by the water rescue dogs and the priority of gazing toward the owner.