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Diverse studies have demonstrated that human body odors (chemosignals) produced during emotional states transfer the emotion experienced during body odor excretion to recipients. If body odors are old and evolutionarily conserved chemosensory cues, then they could have retained their original biochemical signature for the transmission and activation of emotion between species. Recent research has revealed that emotional states can be transmitted from humans to dogs (D’Aniello et al., 2018). The proposed study is designed to investigate the reverse transmission, namely do fear state and rest state induced dog odors transmit these states to humans?

Two theory tried to explain the divergences between the dogs and their ancestral progenitors: the “Domestication hypothesis”, which claims that the origin of most of the dog's behaviors is linked to the genetic processes involved in the domestication, and the “Two-stage hypothesis”, which emphasizes the role of behaviors acquired through individual experiences. This research project has had the purpose of examining the ontogenetic mechanisms that underlie dog-human relationship and communication in the most ancient domestic species. The first aim was to assess if the water rescue training affects the human-dog attachment bond using an adapted version of the “Strange Situation Test”. The second aim was to clarify if following human gestures could be influenced by living in a low socialization regime. The third aim was to evaluate how much the dogs weigh the information given by human (familiar and unfamiliar) posture and voice when they were asked to perform transitive and intransitive actions, and how much this was related to the domestication process. The fourth aim was that of assess whether emotional chemosignals contained in human sweat could affect dogs’ physiology and behavior. Finally, an overview on dog’s sex differences in personality traits as well as cognitive and perceptual processes have been made to explore whether such dissimilarities were affected by the domestication process or the sex-specific differences existing in wild animals have been maintained. All the results presented in this doctoral dissertation converge in emphasising the heavy role of the ontogenetic processes in acquiring socio-cognitive skills, cognitive processes and perception in dogs.

In recent decades, cognitive and behavioral knowledge in dogs seems to have developed considerably, as deduced from the published peer-reviewed articles. However, to date, the worldwide trend of scientific research on dog cognition and behavior has never been explored using a bibliometric approach, while the evaluation of scientific research has increasingly become important in recent years. In this review, we compared the publication trend of the articles in the last 34 years on dogs’ cognitive and behavioral science with those in the general category “Behavioral Science”. We found that, after 2005, there has been a sharp increase in scientific publications on dogs. Therefore, the year 2005 has been used as “starting point” to perform an in-depth bibliometric analysis of the scientific activity in dog cognitive and behavioral studies. The period between 2006 and 2018 is taken as the study period, and a backward analysis was also carried out. The data analysis was performed using “bibliometrix”, a new R-tool used for comprehensive science mapping analysis. We analyzed all information related to sources, countries, affiliations, co-occurrence network, thematic maps, collaboration network, and world map. The results scientifically support the common perception that dogs are attracting the interest of scholars much more now than before and more than the general trend in cognitive and behavioral studies. Both, the changes in research themes and new research themes, contributed to the increase in the scientific production on the cognitive and behavioral aspects of dogs. Our investigation may benefit the researchers interested in the field of cognitive and behavioral science in dogs, thus favoring future research work and promoting interdisciplinary collaborations. Electronic supplementary material The online version of this article (10.1007/s10071-020-01448-2) contains supplementary material, which is available to authorized users.

In many studies that have investigated whether dogs' capacities to understand human pointing gestures are aspects of evolutionary or developmental social competences, family-owned dogs have been compared to shelter dogs. However, for most of these studies, the origins of shelter dogs were unknown. Some shelter dogs may have lived with families before entering shelters, and from these past experiences, they may have learned to understand human gestures. Furthermore, there is substantial variation in the methodology and analytic approaches used in such studies (e.g. different pointing protocols, different treatment of trials with no-choice response and indoor vs. outdoor experimental arenas). Such differences in methodologies and analysis techniques used make it difficult to compare results obtained from different studies and may account for the divergent results obtained. We thus attempted to control for several parameters by carrying out a test on dynamic proximal and distal pointing. We studied eleven kennel dogs of known origin that were born and raised in a kennels with limited human interaction. This group was compared to a group of eleven dogs comparable in terms of breed, sex and age that had lived with human families since they were puppies. Our results demonstrate that pet dogs outperform kennel dogs in their comprehension of proximal and distal pointing, regardless of whether trials where no-choice was made were considered as errors or were excluded from statistical analysis, meaning that dogs living in kennels do not understand pointing gestures. Even if genetic effects of the domestication process on human-dog relationships cannot be considered as negligible, our data suggest that dogs need to learn human pointing gestures and thus underscore the importance of ontogenetic processes.

Water rescue training produces dog-human dyads specialized in rescuing people in the water by promoting a strong cooperative relationship between dogs and their handlers. The present study aims to assess whether this training also affects the human-dog attachment bond using an adapted version of the “Strange Situation Test” (SST), consisting of 7 episodes of 3 min each. Thirteen mutually exclusive and two non-mutually exclusive behaviours were considered. Sixty-five dogs (Labrador and Golden retrievers) were tested: 29 dogs had a Water Rescue Certificate ® (Trained group), 22 dogs had yet to begin the training program (Naive group), and 14 dogs were untrained (Old group) as an age control that was equivalent to the Trained group. All dogs showed a pattern of attachment behaviours with their owners, as they played with and greeted the owner more than the stranger and remained oriented towards the door more in the presence of the stranger during the separation episodes. Furthermore, all groups engaged in play with the stranger more when their owner was present rather than absent (episode 2 vs. 3). The Trained group was less explorative than the Naive and Old groups. Trained dogs engaged in different behaviours not for playing purposes holding a ball in their mouth more than the other groups. Social play behaviours were expressed equally by the Trained and the Naive groups and less in the Old group. Overall, the water rescue training affected the dogs’ behaviour in the SST; however these behavioural differences were (probably) not related to differences in attachment quality.

Simple Summary We explore the differences in male and female dogs regarding personality traits as well as cognitive and perceptual processes. Our aim was to explore whether the differences in male and female dogs were affected by the domestication process. The results show that dogs are largely in line with the life-history theories, reflecting the sex differences described in wild animals. Abstract In this paper, we review the scientific reports of sex-related differences in dogs as compared to the outcomes described for wild animals. Our aim was to explore whether the differences in male and female dogs were affected by the domestication process, in which artificial selection is the main driver. For this purpose, we used information regarding personality traits, cognitive processes, and perception, for which there is a wide theoretical framework in behavioral ecology. Aggressiveness and boldness, described as a behavioral syndrome, were reported as being higher in males than females. Females also seemed more inclined to interspecific social interactions with humans in tasks that require cooperative skills, whereas males appeared more inclined to social play, thus implying different levels of social engagement between the sexes, depending on the context. Studies on cognitive processes underlined a greater flexibility in resorting to a particular navigation strategy in males. Most lateralization studies seem to support the view that males are preferentially left-handed and females are preferentially right-handed. Reports on visual focusing coherently rank females as superior in focusing on single social and physical stimuli. Only male dogs are able to discriminate kin; however, the timing of the olfactory recording in sexes is related to the stimulus relevance. Dogs are largely in line with life-history theories, which indicate that sex differences in dogs are mainly rooted in their biological and evolutionary heritage, remaining unchanged despite artificial selection. In contrast, the higher intraspecific sociability in wild male animals was not replicated in dogs.

Inhibitory control is a collection of several processes that are aimed to refrain from any impulsive response in the subject during inappropriate situations. Evidence suggests that in dogs, the inhibitory control is affected by domestication process, but also experiences during ontogeny could be an important driver in acquiring inhibitory control. The aim of the study was to compare the performance of highly trained dogs (i.e., water rescue dogs) and pet dogs in the A-not-B task. In this procedure, the animals have to inhibit their urge of going to a previous reinforced place. The results showed that the trained dogs committed fewer errors in the task than the pet dogs suggesting a better inhibitory control. This result could indicate that inhibitory control is a flexible ability affected by ontogenetic processes such as the training experience. Fil: Barrera, Gabriela Luciana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Instituto de Ciencias Veterinarias del Litoral. Universidad Nacional del Litoral. Facultad de Ciencias Veterinarias. Instituto de Ciencias Veterinarias del Litoral; Argentina Fil: Alterisio, Alessandra. Università degli Studi di Napoli Federico II; Italia Fil: Scandurra, Anna. Università degli Studi di Napoli Federico II; Italia Fil: Bentosela, Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Investigaciones Médicas. Universidad de Buenos Aires. Facultad de Medicina. Instituto de Investigaciones Médicas; Argentina Fil: D'Aniello, Biagio. Università degli Studi di Napoli Federico II; Italia

We examined the Autonomic Nervous System (ANS) activity of horses in response to human body odors (BOs) produced under happy and fear states. The ANS response of horses was analyzed in terms of Heart Rate Variability (HRV) features extracted in the frequency domain. Our results revealed that human BOs induce sympathetic and parasympathetic changes and stimulate horses emotionally, suggesting interspecies transfer of emotions via BOs. These preliminary findings open the way to measure changes in horse’s ANS dynamics in response to human internal states via human BOs, and allow us to better understand unexpected animal behavior that could compromise human-horse interaction. Moreover, it becomes possible to design more effective strategies to manage animals across a range of situations in which a strict human animal interaction is required, such as the well known Animal Assisted Therapy (AAT).

Simple Summary We tested horses on the impossible task paradigm, a drawback affecting the decision-making process in animals. We used the direction of the horse’s ear cup as an indicator of its visual attention in terms of visual selective attention when both ears were directed at the same target and the visual differential attention when the ears were directed differentially to the persons and to the experimental tools. We aimed to evaluate whether the latter behavior could be considered a possible support to solve the problem. The visual differential attention was the most frequent behavior when the resource was unreachable, which supports the view that this gesture could be linked to a request for help from humans to find the solution to the task. Our procedure proved to be a useful way to understand how horses try to attract human attention when they are in a restricted environment, a typical situation for horses living in stables. Abstract In order to explore the decision-making processes of horses, we designed an impossible task paradigm aimed at causing an expectancy violation in horses. Our goals were to verify whether this paradigm is effective in horses by analyzing their motivation in trying to solve the task and the mode of the potential helping request in such a context. In the first experiment, 30 horses were subjected to three consecutive conditions: no food condition where two persons were positioned at either side of a table in front of the stall, solvable condition when a researcher placed a reachable reward on the table, and the impossible condition when the food was placed farther away and was unreachable by the horse. Eighteen horses were used in the second experiment with similar solvable and impossible conditions but in the absence of people. We measured the direction of the horse’s ear cup as an indicator of its visual attention in terms of visual selective attention (VSA) when both ears were directed at the same target and the visual differential attention (VDA) when the ears were directed differentially to the persons and to the table. We also included tactile interaction toward table and people, the olfactory exploration of the table, and the frustration behaviors in the ethogram. In the first experiment, the VDA was the most frequent behavior following the expectancy violation. In the second experiment, horses showed the VDA behavior mostly when people and the unreachable resource were present at the same time. We speculate that the VDA could be a referential gesture aimed to link the solution of the task to the people, as a request for help.

We report a study examining interspecies emotion transfer via body odors (chemosignals). Do human body odors (chemosignals) produced under emotional conditions of happiness and fear provide information that is detectable by pet dogs (Labrador and Golden retrievers)? The odor samples were collected from the axilla of male donors not involved in the main experiment. The experimental setup involved the co-presence of the dog's owner, a stranger and the odor dispenser in a space where the dogs could move freely. There were three odor conditions [fear, happiness, and control (no sweat)] to which the dogs were assigned randomly. The dependent variables were the relevant behaviors of the dogs (e.g., approaching, interacting and gazing) directed to the three targets (owner, stranger, sweat dispenser) aside from the dogs' stress and heart rate indicators. The results indicated with high accuracy that the dogs manifested the predicted behaviors in the three conditions. There were fewer and shorter owner directed behaviors and more stranger directed behaviors when they were in the "happy odor condition" compared to the fear odor and control conditions. In the fear odor condition, they displayed more stressful behaviors. The heart rate data in the control and happy conditions were significantly lower than in the fear condition. Our findings suggest that interspecies emotional communication is facilitated by chemosignals. University of Naples “Federico II”; Fundação para a Ciência e a Tecnologia (FCT) info:eu-repo/semantics/publishedVersion

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.

We assessed how highly trained dogs respond to gestural versus verbal signals when their handlers oran unfamiliar person asked them to perform an obedience task. Dogs were requested to perform fourdifferent actions (“Sit”, “Down”, “Stay” and “Come”) upon receiving congruent (only gestural or onlyverbal) or incongruent signals (gestural and verbal signals contradict each other).The dogs’ performance measures were the frequency of correct responses and their response latency.Generalized Estimation Equation models were used to determine whether the type of signal, the coher-ence of the signals and familiarity with the signaler influenced dogs’ responses.Our results show that the probability of dogs expressing the requested behaviour was lower when thestranger gave verbal signals, than in any of the other conditions. In the incongruent condition, the prob-ability that dogs expressed the behaviour indicated by the verbal signal was lower for signals providedby the stranger than for signals provided by the owner. The reverse was observed for gestural signals. Ingeneral, longer latencies to perform the “Come”, “Down” and “Sit” behaviours were observed in responseto the stranger’s verbal signals than when the stranger gave gestural or incongruent signals. Additionally,the response latency to the stranger’s verbal stimuli took longer than verbal stimuli were provided bythe owner in the case of “Come” (P = 0.002) and “Sit” (P < 0.001) actions.Our data support the argument that for highly trained dogs, gestural signals are less dependent uponsignal-giver familiarity, whereas verbal signals are less effective when they are given by an unfamiliarperson. Fundação para a Ciência e a tecnologia (FCT); University of Naples “Federico II” info:eu-repo/semantics/publishedVersion

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.