A citizen science model turns anecdotes into evidence by revealing similar characteristics among Gifted Word Learner dogs.

Dogs that have a vocabulary of object labels (Gifted Word Learner dogs-GWL dogs) have great potential as a comparative model for studying a variety of cognitive mechanisms. However, only a handful of studies, with a small sample size of 1 or 2 dogs, have examined this phenomenon. GWL dogs appear to share many of the same distinctive characteristics, but due to their rarity, it is not clear if these similarities are only anecdotal or indeed reflect characteristics that are similar in these rare individuals. Here we present the first study conducted on a relatively large sample of 41 GWL dogs that were recruited and tested using a citizen science model. After testing the dogs' receptive vocabulary of toy names, we asked the owners to complete a questionnaire about their and their dog's life experiences. Our findings highlight several characteristics that are shared among most GWL dogs, such as their learning speed, their large vocabulary, and that they learned the names of the toys spontaneously, without the explicit intent of their owners. Our findings validate previous anecdotal evidence on common characteristics of GWL dogs and supply additional support to the hypothesis that these dogs represent a unique group of dogs.

Two valid and reliable tests for monitoring age-related memory performance and neophobia differences in dogs.

The prolonged lifespan of companion dogs has resulted in increased behavioural and physical challenges linked to old age. The development of behavioural tests to identify and monitor age-related differences has begun. However, standardised testing requires validation. The present study aimed to assess external validity, interobserver reliability, and test-retest reliability of an indoor test battery for the rapid assessment of age-related behavioural differences in dogs. Two experimenters tested young dogs (N = 20, mean age ± SD = 2.7 ± 0.4 years) and old dogs (N = 18, mean age ± SD = 11.8 ± 1.3 years) in the test battery once and then again after two weeks. Our results found external validity for two subtests out of six. On both test occasions, old dogs committed more errors than young dogs in a memory subtest and showed more object avoidance when encountering a novel object. Interobserver reliability and test-retest reliability was high. We conclude that the Memory and Novel object subtests are valid and reliable for monitoring age-related memory performance and object neophobic differences in dogs.

Multisensory mental representation of objects in typical and Gifted Word Learner dogs.

Little research has been conducted on dogs' (Canis familiaris) ability to integrate information obtained through different sensory modalities during object discrimination and recognition tasks. Such a process would indicate the formation of multisensory mental representations. In Experiment 1, we tested the ability of 3 Gifted Word Learner (GWL) dogs that can rapidly learn the verbal labels of toys, and 10 Typical (T) dogs to discriminate an object recently associated with a reward, from distractor objects, under light and dark conditions. While the success rate did not differ between the two groups and conditions, a detailed behavioral analysis showed that all dogs searched for longer and sniffed more in the dark. This suggests that, when possible, dogs relied mostly on vision, and switched to using only other sensory modalities, including olfaction, when searching in the dark. In Experiment 2, we investigated whether, for the GWL dogs (N = 4), hearing the object verbal labels activates a memory of a multisensory mental representation. We did so by testing their ability to recognize objects based on their names under dark and light conditions. Their success rate did not differ between the two conditions, whereas the dogs' search behavior did, indicating a flexible use of different sensory modalities. Little is known about the cognitive mechanisms involved in the ability of GWL dogs to recognize labeled objects. These findings supply the first evidence that for GWL dogs, verbal labels evoke a multisensory mental representation of the objects.

An exploratory analysis of head-tilting in dogs.

Little is known about head-tilts in dogs. Based on previous investigations on the head turning and the lateralised brain pattern of human speech processing in dogs, we hypothesised that head-tilts may be related to increased attention and could be explained by lateralised mental functions. We observed 40 dogs during object-label knowledge tests and analysed head-tilts occurring while listening to humans requesting verbally to fetch a familiar toy. Our results indicate that only dogs that had learned the name of the objects tilted their heads frequently. Besides, the side of the tilt was stable across several months and tests. Thus, we suggest a relationship between head-tilting and processing relevant, meaningful stimuli.

Acquisition and long-term memory of object names in a sample of Gifted Word Learner dogs.

Dogs with a vocabulary of object names are rare and are considered uniquely gifted. In a few cases, these Gifted Word Learner (GWL) dogs have presented cognitive skills that are functionally similar to those of human infants. However, the acquisition rate of new object names and the ability of GWL dogs to form long-term memories of those is unknown. In this study, we examine the ability of six GWL dogs to acquire the names of new objects in a short period and to retain those in their long-term memory without post-acquisition exposures. In Experiments 1 and 2, the dogs were tested on their ability to learn, during social interactions with their owners, the names of 6 and 12 new toys respectively, in one week. In Experiments 3 and 4, the dogs' memory of these objects was tested after one and two months. GWL dogs typically learned the names of the new objects and remembered those. We suggest that dogs with knowledge of object names could be a powerful model for studying mental mechanisms related to word acquisition in a non-human species.

Word learning dogs (Canis familiaris) provide an animal model for studying exceptional performance.

Exceptional performance is present in various human activities but its origins are debated and challenging to study. We report evidence of exceptional performance and qualitative variation in learning object-names in dogs. 34 naïve family dogs and 6 knowledgeable individuals that knew multiple toy names, found in 2 years of search around the Globe, were exposed to 3 months of training to learn two novel toy-names and were tested in two-way choice tests. Only 1 naïve and all 6 knowledgeable dogs passed the tests. Additionally, only these dogs learned at least 10 new toy names over the 3 months, showing qualitative variation in this capacity. Although previous object-name knowledge could provide an explanation for the superior performance of the knowledgeable dogs, their rarity and the absence of previous training of this skill point to exceptional giftedness in these individuals, providing the basis to establish dogs as a model-species for studying talent.

Did we find a copycat? Do as I Do in a domestic cat (Felis catus).

This study shows evidence of a domestic cat (Felis catus) being able to successfully learn to reproduce human-demonstrated actions based on the Do as I Do paradigm. The subject was trained to reproduce a small set of familiar actions on command "Do it!" before the study began. To test feature-contingent behavioural similarity and control for stimulus enhancement, our test consisted of a modified version of the two-action procedure, combined with the Do as I Do paradigm. Instead of showing two different actions on an object to different subjects, we applied a within-subject design and showed the two actions to the same subject in separate trials. We show evidence that a well-socialized companion cat was able to reproduce actions demonstrated by a human model by reproducing two different actions that were demonstrated on the same object. Our experiment provides the first evidence that the Do as I Do paradigm can be applied to cats, suggesting that the ability to recognize behavioural similarity may fall within the range of the socio-cognitive skills of this species. The ability of reproducing the actions of a heterospecific human model in well-socialized cats may pave the way for future studies addressing cats' imitative skills.

Digital Endocasting in Comparative Canine Brain Morphology.

Computed tomography (CT) is one of the most useful techniques for digitizing bone structures and making endocranial models from the neurocranium. The resulting digital endocasts reflect the morphology of the brain and the associated structures. Our first aim was to document the methodology behind creating detailed digital endocasts of canine skulls. We created digital endocasts of the skulls of 24 different dog breeds and 4 wild canids for visualization and teaching purposes. We used CT scanning with 0.323 mm × 0.322 mm × 0.6 mm resolution. The imaging data were segmented with 3D Slicer software and refined with Autodesk Meshmixer. Images were visualized in 3D Slicer and surface models were converted to 3D PDFs to provide easier interactive access, and 3D prints were also generated for visualization purposes. Our second aim was to analyze how skull length and width relate to the surface areas of the prepiriform rhinencephalic, prefrontal, and non-prefrontal cerebral convexity areas of the endocasts. The rhinencephalic area ratio decreased with a larger skull index. Our results open the possibility to analyze the relationship between the skull and brain morphology, and to link certain features to behavior, and cognition in dogs.

A wolfdog point of view on the impossible task paradigm.

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

Wolves (Canis lupus) and dogs (Canis familiaris) differ in following human gaze into distant space but respond similar to their packmates' gaze.

Gaze following into distant space is defined as visual co-orientation with another individual's head direction allowing the gaze follower to gain information on its environment. Human and nonhuman animals share this basic gaze following behavior, suggested to rely on a simple reflexive mechanism and believed to be an important prerequisite for complex forms of social cognition. Pet dogs differ from other species in that they follow only communicative human gaze clearly addressed to them. However, in an earlier experiment we showed that wolves follow human gaze into distant space. Here we set out to investigate whether domestication has affected gaze following in dogs by comparing pack-living dogs and wolves raised and kept under the same conditions. In Study 1 we found that in contrast to the wolves, these dogs did not follow minimally communicative human gaze into distant space in the same test paradigm. In the observational Study 2 we found that pack-living dogs and wolves, similarly vigilant to environmental stimuli, follow the spontaneous gaze of their conspecifics similarly often. Our findings suggest that domestication did not affect the gaze following ability of dogs itself. The results raise hypotheses about which other dog skills might have been altered through domestication that may have influenced their performance in Study 1. Because following human gaze in dogs might be influenced by special evolutionary as well as developmental adaptations to interactions with humans, we suggest that comparing dogs to other animal species might be more informative when done in intraspecific social contexts. (PsycINFO Database Record