Do Dogs Provide Information Helpfully?

Dogs are particularly skilful during communicative interactions with humans. Dogs’ abilities to use human communicative cues in cooperative contexts outcompete those of other species, and might be the result of selection pressures during domestication. Dogs also produce signals to direct the attention of humans towards outside entities, a behaviour often referred to as showing behaviour. This showing behaviour in dogs is thought to be something dogs use intentionally and referentially. However, there is currently no evidence that dogs communicate helpfully, i.e. to inform an ignorant human about a target that is of interest to the human but not to the dog. Communicating with a helpful motive is particularly interesting because it might suggest that dogs understand the human’s goals and need for information. In study 1, we assessed whether dogs would abandon an object that they find interesting in favour of an object useful for their human partner, a random novel distractor, or an empty container. Results showed that it was mainly self-interest that was driving the dogs’ behaviour. The dogs mainly directed their behaviour towards the object they had an interest in, but dogs were more persistent when showing the object relevant to the human, suggesting that to some extent they took the humans interest into account. Another possibility is that dogs’ behaviour was driven by an egocentric motivation to interact with novel targets and that the dogs’ neophila might have masked their helpful tendencies. Therefore, in study 2 the dogs had initial access to both objects, and were expected to indicate only one (relevant or distractor). The human partner interacted with the dog using vocal communication in half of the trials, and remaining silent in the other half. Dogs from both experimental groups, i.e. indicating the relevant object or indicating the distractor, established joint attention with the human. However, the human’s vocal communication and the presence of the object relevant to the human increased the persistency of showing, supporting the hypothesis that the dogs understood the objects’ relevance to the human. We propose two non-exclusive explanations. These results might suggest that informative motives could possibly underlie dogs’ showing. It is also possible that dogs might have indicated the location of the hidden object because they recognised it as the target of the human’s search. This would be consistent with taking into account the objects’ relevance, without necessarily implying that the dogs understood the human’s state of knowledge.

Related papers:

title: Use of experimenter-given cues in dogs
abstract: Since the observations of O. Pfungst the use of human-provided cues by animals has been well-known in the behavioural sciences (“Clever Hans effect”). It has recently been shown that rhesus monkeys (Macaca mulatta) are unable to use the direction of gazing by the experimenter as a cue for finding food, although after some training they learned to respond to pointing by hand. Direction of gaze is used by chimpanzees, however. Dogs (Canis familiaris) are believed to be sensitive to human gestural communication but their ability has never been formally tested. In three experiments we examined whether dogs can respond to cues given by humans. We found that dogs are able to utilize pointing, bowing, nodding, head-turning and glancing gestures of humans as cues for finding hidden food. Dogs were also able to generalize from one person (owner) to another familiar person (experimenter) in using the same gestures as cues. Baseline trials were run to test the possibility that odour cues alone could be responsible for the dogs’ performance. During training individual performance showed limited variability, probably because some dogs already “knew” some of the cues from their earlier experiences with humans. We suggest that the phenomenon of dogs responding to cues given by humans is better analysed as a case of interspecific communication than in terms of discrimination learning.

title: A comparative analysis of animals' understanding of the human pointing gesture
abstract: We review studies demonstrating the ability of some animals to understand the human pointing gesture. We present a 3-step analysis of the topic. (1) We compare and evaluate current experimental methods (2) We compare available experimental results on performance of different species and investigate the interaction of species differences and other independent variables (3) We evaluate how our present understanding of pointing comprehension answers questions about function, evolution and mechanisms. Recently, a number of different hypotheses have been put forward to account for the presence of this ability in some species and for the lack of such comprehension in others. In our view, there is no convincing evidence for the assumption that the competitive lifestyles of apes would inhibit the utilization of this human gesture. Similarly, domestication as a special evolutionary factor in the case of some species falls short in explaining high levels of pointing comprehension in some non-domestic species. We also disagree with the simplistic view of describing the phenomenon as a simple form of conditioning. We suggest that a more systematic comparative research is needed to understand the emerging communicative representational abilities in animals that provide the background for comprehending the human pointing gesture.

title: Comprehension of human communicative signs in pet dogs (Canis familiaris).
abstract: On the basis of a study by D. J. Povinelli, D. T. Bierschwale, and C. G. Cech (1999), the performance of family dogs (Canis familiaris) was examined in a 2-way food choice task in which 4 types of directional cues were given by the experimenter: pointing and gazing, head-nodding ("at target"), head turning above the correct container ("above target"), and glancing only ("eyes only"). The results showed that the performance of the dogs resembled more closely that of the children in D. J. Povinelli et al.'s study, in contrast to the chimpanzees' performance in the same study. It seems that dogs, like children, interpret the test situation as being a form of communication. The hypothesis is that this similarity is attributable to the social experience and acquired social routines in dogs because they spend more time in close contact with humans than apes do, and as a result dogs are probably more experienced in the recognition of human gestures.

title: Communication of Food Location Between Human and Dog ( Canis Familiaris )
abstract: Two domestic dogs (Canis familiaris) participated in a series of studies in which they communicated with a human about the location of hidden food. In the first study both dogs were able to follow human pointing reliably to one of several locations where food was hidden, both in front of them and behind them. They also showed some skills at following human gaze direction in this same task, when both head and eyes indicated the same location. They did not follow eye direction when it conflicted with head direction. A second study clearly ruled out a low-level visual tracking explanation for at least one of the subjects. In a third study one of the two dogs was able to lead a naive human to one of three locations containing food consistently, mainly by barking and orienting its body to the food. The subject did not behave differently, however, when the human turned his back or covered his eyes; he continued to orient to the food and bark under all conditions. In a fourth study in which more clearly visual signals were involved, both subjects strongly preferred to drop a retrieved object at the front of, rather than at the back of, the human — even when the human turned his back so that subjects had to bring the object around his body upon return. The knowledge of human pointing and gaze direction displayed by these two domestic dogs is in many ways comparable to that displayed in experimental studies by nonhuman primates.

title: Dogs' (Canis familiaris) responsiveness to human pointing gestures.
abstract: In a series of 3 experiments, dogs (Canis familiaris) were presented with variations of the human pointing gesture: gestures with reversed direction of movement, cross-pointing, and different arm extensions. Dogs performed at above chance level if they could see the hand (and index finger) protruding from the human body contour. If these minimum requirements were not accessible, dogs still could rely on the body position of the signaler. The direction of movement of the pointing arm did not influence the performance. In summary, these observations suggest that dogs are able to rely on relatively novel gestural forms of the human communicative pointing gesture and that they are able to comprehend to some extent the referential nature of human pointing.

title: Effects of selection for cooperation and attention in dogs
abstract: BackgroundIt has been suggested that the functional similarities in the socio-cognitive behaviour of dogs and humans emerged as a consequence of comparable environmental selection pressures. Here we use a novel approach to account for the facilitating effect of domestication in dogs and reveal that selection for two factors under genetic influence (visual cooperation and focused attention) may have led independently to increased comprehension of human communicational cues.MethodIn Study 1, we observed the performance of three groups of dogs in utilizing the human pointing gesture in a two-way object choice test. We compared breeds selected to work while visually separated from human partners (N = 30, 21 breeds, clustered as independent worker group), with those selected to work in close cooperation and continuous visual contact with human partners (N = 30, 22 breeds, clustered as cooperative worker group), and with a group of mongrels (N = 30).Secondly, it has been reported that, in dogs, selective breeding to produce an abnormal shortening of the skull is associated with a more pronounced area centralis (location of greatest visual acuity). In Study 2, breeds with high cephalic index and more frontally placed eyes (brachycephalic breeds, N = 25, 14 breeds) were compared with breeds with low cephalic index and laterally placed eyes (dolichocephalic breeds, N = 25, 14 breeds).ResultsIn Study 1, cooperative workers were significantly more successful in utilizing the human pointing gesture than both the independent workers and the mongrels.In study 2, we found that brachycephalic dogs performed significantly better than dolichocephalic breeds.DiscussionAfter controlling for environmental factors, we have provided evidence that at least two independent phenotypic traits with certain genetic variability affect the ability of dogs to rely on human visual cues. This finding should caution researchers against making simple generalizations about the effects of domestication and on dog-wolf differences in the utilization of human visual signals.

title: The Domestication of Social Cognition in Dogs
abstract: Dogs are more skillful than great apes at a number of tasks in which they must read human communicative signals indicating the location of hidden food. In this study, we found that wolves who were raised by humans do not show these same skills, whereas domestic dog puppies only a few weeks old, even those that have had little human contact, do show these skills. These findings suggest that during the process of domestication, dogs have been selected for a set of social-cognitive abilities that enable them to communicate with humans in unique ways.

title: The early ontogeny of human–dog communication
abstract: Although dogs, Canis familiaris, are skilful at responding to human social cues, the role of ontogeny in the development of these abilities has not been systematically examined. We studied the ability of very young dog puppies to follow human communicative cues and successfully find hidden food. In the first experiment we compared 6-, 8-, 16- and 24-week-old puppies in their ability to use pointing gestures or a marker as a cue. The results showed that puppies, independent of age, could use all human communicative cues provided; only their success at using the marker cue increased with age. In the second and third experiments we investigated the flexibility of the puppies' understanding by reducing the degree to which they could use local enhancement to solve these problems. Here, subjects could not simply approach the hand of the experimenter and follow its direction to the correct location because cups were placed next to the dog instead of next to the experimenter. Six-week-old puppies readily used all of the human communicative cues provided. These findings support the hypothesis that domestication played a critical role in shaping the ability of dogs to follow human-given cues.

title: A Simple Reason for a Big Difference Wolves Do Not Look Back at Humans, but Dogs Do
abstract: The present investigations were undertaken to compare interspecific communicative abilities of dogs and wolves, which were socialized to humans at comparable levels. The first study demonstrated that socialized wolves were able to locate the place of hidden food indicated by the touching and, to some extent, pointing cues provided by the familiar human experimenter, but their performance remained inferior to that of dogs. In the second study, we have found that, after undergoing training to solve a simple manipulation task, dogs that are faced with an insoluble version of the same problem look/gaze at the human, while socialized wolves do not. Based on these observations, we suggest that the key difference between dog and wolf behavior is the dogs' ability to look at the human's face. Since looking behavior has an important function in initializing and maintaining communicative interaction in human communication systems, we suppose that by positive feedback processes (both evolutionary and ontogenetically) the readiness of dogs to look at the human face has lead to complex forms of dog-human communication that cannot be achieved in wolves even after extended socialization.

title: Comprehension of human pointing gestures in young human-reared wolves (Canis lupus) and dogs (Canis familiaris)
abstract: Dogs have a remarkable skill to use human-given cues in object-choice tasks, but little is known to what extent their closest wild-living relative, the wolf can achieve this performance. In Study 1, we compared wolf and dog pups hand-reared individually and pet dogs of the same age in their readiness to form eye-contact with a human experimenter in an object-choice task and to follow her pointing gesture. The results showed that dogs already at 4 months of age use momentary distal pointing to find hidden food even without intensive early socialization. Wolf pups, on the contrary, do not attend to this subtle pointing. Accordingly in Studies 2 and 3, these wolves were tested longitudinally with this and four other (easier) human-given cues. This revealed that wolves socialized at a comparable level to dogs are able to use simple human-given cues spontaneously if the human’s hand is close to the baited container (e.g. touching, proximal pointing). Study 4 showed that wolves can follow also momentary distal pointing similarly to dogs if they have received extensive formal training. Comparing the wolves to naïve pet dogs of the same age revealed that during several months of formal training wolves can reach the level of dogs in their success of following momentary distal pointing in parallel with improving their readiness to form eye-contact with a human experimenter. We assume that the high variability in the wolves’ communicative behaviour might have provided a basis for selection during the course of domestication of the dog.

title: Wolves outperform dogs in following human social cues
abstract: Domestic dogs, Canis familiaris, have been shown capable of finding hidden food by following pointing gestures made with different parts of the human body. However, previous studies have reported that hand-reared wolves, C. lupus, fail to locate hidden food in response to similar points in the absence of extensive training. The failure of wolves to perform this task has led to the proposal that the ability to understand others' intentions is a derived character in dogs, not present in the ancestral population (wolves). Here we show that wolves, given the right rearing environment and daily interaction with humans, can use momentary distal human pointing cues to find food without training, whereas dogs tested outdoors and dogs at an animal shelter do not follow the same human points. In line with past studies, pet dogs tested indoors were successful in following these points. We also show that the reported failure of wolves in some past studies may be due to differences in the testing environment. Our findings indicate that domestication is not a prerequisite for human-like social cognition in canids, and show the need for additional research on the role of rearing conditions and environmental factors in the development of higher-level cognitive abilities.

title: Comparative social cognition: what can dogs teach us?
abstract: Research in comparative social cognition addresses how challenges of social living have formed the cognitive structures that control behaviours involved in communication, social learning and social understanding. In contrast to the traditional psychological approach, recent investigations take both evolutionary and functional questions into account, but the main emphasis is still on the mechanisms of behaviour. Although in traditional research ‘comparative’ meant mainly comparisons between humans and other primates, ethological influences have led to a broadening of the spectrum of species under study. In this review, we evaluated how the study of dogs broadens our understanding of comparative social cognition. In the early days of ethology, dogs enjoyed considerable interest from ethologists, but during the last 20 years, dogs have rarely been studied by ethological methods. Through a complex evolutionary process, dogs became adapted for living in human society; therefore, the human environment and social setting now represents a natural ecological niche for this species. We have evidence that dogs have been selected for adaptations to human social life, and that these adaptations have led to marked changes in their communicative, social, cooperative and attachment behaviours towards humans. Until now, the study of dogs was hindered by the view that they represent an ‘artificial’ species, but by accepting that dogs are adapted to their niche, as are other ‘natural’ species, comparative investigations can be put into new light.

title: Complete Mitochondrial Genomes of Ancient Canids Suggest a European Origin of Domestic Dogs
abstract: Dog Domestication The precise details of the domestication and origins of domestic dogs are unclear. Thalmann et al. (p. 871; see the cover) analyzed complete mitochondrial genomes from present-day dogs and wolves, as well as 18 fossil canids dating from 1000 to 36,000 years ago from the Old and New Worlds. The data suggest that an ancient, now extinct, central European population of wolves was directly ancestral to domestic dogs. Furthermore, several ancient dogs may represent failed domestication events. Ancient DNA suggests that dog domestication was complex and likely originated in Europe. The geographic and temporal origins of the domestic dog remain controversial, as genetic data suggest a domestication process in East Asia beginning 15,000 years ago, whereas the oldest doglike fossils are found in Europe and Siberia and date to >30,000 years ago. We analyzed the mitochondrial genomes of 18 prehistoric canids from Eurasia and the New World, along with a comprehensive panel of modern dogs and wolves. The mitochondrial genomes of all modern dogs are phylogenetically most closely related to either ancient or modern canids of Europe. Molecular dating suggests an onset of domestication there 18,800 to 32,100 years ago. These findings imply that domestic dogs are the culmination of a process that initiated with European hunter-gatherers and the canids with whom they interacted.

title: The genomics of selection in dogs and the parallel evolution between dogs and humans.
abstract: The genetic bases of demographic changes and artificial selection underlying domestication are of great interest in evolutionary biology. Here we perform whole-genome sequencing of multiple grey wolves, Chinese indigenous dogs and dogs of diverse breeds. Demographic analysis show that the split between wolves and Chinese indigenous dogs occurred 32,000 years ago and that the subsequent bottlenecks were mild. Therefore, dogs may have been under human selection over a much longer time than previously concluded, based on molecular data, perhaps by initially scavenging with humans. Population genetic analysis identifies a list of genes under positive selection during domestication, which overlaps extensively with the corresponding list of positively selected genes in humans. Parallel evolution is most apparent in genes for digestion and metabolism, neurological process and cancer. Our study, for the first time, draws together humans and dogs in their recent genomic evolution.

title: Ancient Wolf Genome Reveals an Early Divergence of Domestic Dog Ancestors and Admixture into High-Latitude Breeds
abstract: The origin of domestic dogs is poorly understood [1-15], with suggested evidence of dog-like features in fossils that predate the Last Glacial Maximum [6, 9, 10, 14, 16] conflicting with genetic estimates of a more recent divergence between dogs and worldwide wolf populations [13, 15, 17-19]. Here, we present a draft genome sequence from a 35,000-year-old wolf from the Taimyr Peninsula in northern Siberia. We find that this individual belonged to a population that diverged from the common ancestor of present-day wolves and dogs very close in time to the appearance of the domestic dog lineage. We use the directly dated ancient wolf genome to recalibrate the molecular timescale of wolves and dogs and find that the mutation rate is substantially slower than assumed by most previous studies, suggesting that the ancestors of dogs were separated from present-day wolves before the Last Glacial Maximum. We also find evidence of introgression from the archaic Taimyr wolf lineage into present-day dog breeds from northeast Siberia and Greenland, contributing between 1.4% and 27.3% of their ancestry. This demonstrates that the ancestry of present-day dogs is derived from multiple regional wolf populations.

title: The domestic dog : its evolution, behaviour, and interactions with people
abstract: 1.  James Serpell Part I. Domestication and Evolution: 2. Origins of the dog: domestication and early history Juliet Clutton-Brock 3. Evolution of working dogs Raymond Coppinger, and Richard Schneider Part II. Behaviour and Behaviour Problems: 4. Genetic aspects of dog behaviour with particular reference to working ability M. B. Willis 5. Analysing breed and gender differences in behaviour Benjamin L. Hart 6. Early experience and the development of behaviour James Serpell, and J. A. Jagoe 7. Feeding behaviour of domestic dogs and the role of experience Chris Thorne 8. Social and communication behaviour of companion dogs John W. S. Bradshaw, and Helen M. R. Nott 9. The ethology and epidemiology of canine aggression Randall Lockwood 10. Canine behavioural therapy Roger A. Mugford 11. Effects of owner personality and attitudes on dog behaviour Valerie O'Farrell Part III. Human- Dogs as human companions: a review of the relationshipLynette A. Hart 13. The welfare of dogs in human care Robert Hubrecht 14. Variation in dog society: between resource dispersion and social flux? D. W. Macdonald, and G. M. Carr 15. Population biology and ecology of feral dogs in central Italy L. Boitani, F. Francisci, P. Ciucci, and G. Andreoli 16. From paragon to pariah: some reflections on human attitudes to dogs James Serpell 17. The hair of the dog James Serpell Index.

title: Do dogs get the point? A review of dog-human communication ability
abstract: In recent years evidence has accumulated demonstrating that dogs are, to a degree, skilful in using human forms of communication, making them stand out in the animal kingdom. Neither man's closest relative, the chimpanzee, nor dog's closest living relative, the wolf, can use human communication as flexibly as the domestic dog. This has led to the hypothesis that dogs’ skills in this domain may be a result of selection pressures during domestication, which have shaped dogs’ skills tremendously. One hypothesis, the so-called by-product hypothesis, suggests that dogs have been selected against fear and aggression and as a by-product this paved the way for the evolution of generally more flexible social cognitive skills, which surpassed those of their ancestor, the wolf. Another hypothesis, the adaptation hypothesis, has claimed that dogs may have been specifically selected for certain tasks for which using human forms of communication was necessary. As of yet, the mechanism underlying dogs’ understanding of human forms of communication is not fully understood. We argue here that understanding the mechanism involved will also shed light on possible evolutionary scenarios. We argue that the evidence to date suggests that dogs’ understanding of human forms of communication may be more specialized than was predicted by some and may be best explained as the result of a special adaptation of dogs to the specific activities humans have used them for.

title: Human-like social skills in dogs?
abstract: Domestic dogs are unusually skilled at reading human social and communicative behavior--even more so than our nearest primate relatives. For example, they use human social and communicative behavior (e.g. a pointing gesture) to find hidden food, and they know what the human can and cannot see in various situations. Recent comparisons between canid species suggest that these unusual social skills have a heritable component and initially evolved during domestication as a result of selection on systems mediating fear and aggression towards humans. Differences in chimpanzee and human temperament suggest that a similar process may have been an important catalyst leading to the evolution of unusual social skills in our own species. The study of convergent evolution provides an exciting opportunity to gain further insights into the evolutionary processes leading to human-like forms of cooperation and communication.

title: Intentional behaviour in dog-human communication: an experimental analysis of “showing” behaviour in the dog
abstract: Despite earlier scepticism there is now evidence for simple forms of intentional and functionally referential communication in many animal species. Here we investigate whether dogs engage in functional referential communication with their owners. “Showing” is defined as a communicative action consisting of both a directional component related to an external target and an attention-getting component that directs the attention of the perceiver to the informer or sender. In our experimental situation dogs witness the hiding of a piece of food (or a favourite toy) which they cannot get access to. We asked whether dogs would engage in “showing” in the presence of their owner. To control for the motivational effects of both the owner and the food on the dogs’ behaviour, control observations were also staged where only the food (or the toy) or the owner was present. Dogs’ gazing frequency at both the food (toy) and the owner was greater when only one of these was present. In other words, dogs looked more frequently at their owner when the food (toy) was present, and they looked more at the location of the food (toy) when the owner was present. When both the food (toy) and the owner were present a new behaviour, “gaze alternation”, emerged which was defined as changing the direction of the gaze from the location of the food (toy) to looking at the owner (or vice versa) within 2 s. Vocalisations that occurred in this phase were always associated with gazing at the owner or the location of the food. This behaviour, which was specific to this situation, has also been described in chimpanzees, a gorilla and humans, and has often been interpreted as a form of functionally referential communication. Based on our observations we argue that dogs might be able to engage in functionally referential communication with their owner, and their behaviour could be described as a form of “showing”. The contribution of domestication and individual learning to the well-developed communicative skills in dogs is discussed and will be the subject of further studies.

title: Intentionality as measured in the persistence and elaboration of communication by chimpanzees (Pan troglodytes).
abstract: In human infancy, 2 criteria for intentional communication are (a) persistence in and (b) elaboration of communication when initial attempts to communicate fail. Twenty-nine chimpanzees (Pan troglodytes) were presented with both desirable (a banana) and undesirable food (commercial primate chow). Three conditions were administered: (a) the banana was delivered (successful communication), (b) half of the banana was delivered (partially successful communication), and (c) the chow was delivered (failed communication). The chimpanzees exhibited persistence in and elaboration of their communication in every condition except when the banana was delivered. Thus, their communication was about a specific item, demonstrating that both intentionality and nonverbal reference are capacities shared by humans with our nearest living relatives, the great apes.

title: Marked referential communicative behaviours, but no differentiation of the “knowledge state” of humans in untrained pet dogs versus 1-year-old infants
abstract: The study examines whether untrained dogs and infants take their caregiver’s visual experience into account when communicating with them. Fifteen adult dogs and 15 one-year-old infants were brought into play with their caregivers with one of their own toys. The caregiver gave the toy to the experimenter, who, in different conditions, placed it either above or under one of two containers, with both the infant or dog and the caregiver witnessing the positioning; in a third condition, the caregiver left the room before the toy was placed under one of the two containers and later returned. Afterwards, for each condition, the caregiver asked the participant to indicate the location of the toy. Neither dogs nor infants—untrained to the use of the partner’s knowledge state—showed much difference of behaviour between the three conditions. However, dogs showed more persistence for most behaviours (gaze at the owner, gaze at the toy and gaze alternation) and conditions, suggesting that the situation made more demands on dogs’ communicative behaviours than on those of infants. When all deictic behaviours of infants (arm points towards the toy and gaze at the toy) were taken into account, dogs and infants did not differ. Phylogeny, early experience and ontogeny may all play a role in the ways that both species communicate with adult humans.

title: Gaze alternation in dogs and toddlers in an unsolvable task: evidence of an audience effect
abstract: Dogs have been shown to use human-directed gazing behaviour and gaze alternation in numerous contexts; however, it is still unclear whether this behaviour can be considered an intentional and referential communicative act. In the current study, adult dogs and preverbal toddlers were tested using the classic unsolvable task paradigm, but varying the attentional stance of the participating audience (the experimenter and the caregiver). The aims were to assess (1) whether dogs and toddlers would use gaze alternation behaviour in similar manners when the task became unsolvable, and (2) whether both dogs and toddlers would take into account the attentional stance of the audience when initiating a communicative interaction. Results indicated that both toddlers and dogs increased their gaze alternation behaviour between the apparatus and caregiver when the task became unsolvable, and toddlers also showed an increase in pointing behaviour. Furthermore, both species showed a capacity to take into account the attentional stance of the audience when manifesting gaze alternation behaviours towards them. Taken together, these results suggest that gaze alternation is both an intentional and referential communicative act and that both species can take into account the need for audience attention when communicating with them.

title: 12- and 18-Month-Olds Point to Provide Information for Others
abstract: Classically, infants are thought to point for 2 main reasons: (a) They point imperatively when they want an adult to do something for them (e.g., give them something; "Juice!"), and (b) they point declaratively when they want an adult to share attention with them to some interesting event or object ("Look!"). Here we demonstrate the existence of another motive for infants' early pointing gestures: to inform another person of the location of an object that person is searching for. This informative motive for pointing suggests that from very early in ontogeny humans conceive of others as intentional agents with informational states and they have the motivation to provide such information communicatively.

title: Twelve-month-olds communicate helpfully and appropriately for knowledgeable and ignorant partners
abstract: In the current study we investigated whether 12-month-old infants gesture appropriately for knowledgeable versus ignorant partners, in order to provide them with needed information. In two experiments we found that in response to a searching adult, 12-month-olds pointed more often to an object whose location the adult did not know and thus needed information to find (she had not seen it fall down just previously) than to an object whose location she knew and thus did not need information to find (she had watched it fall down just previously). These results demonstrate that, in contrast to classic views of infant communication, infants' early pointing at 12 months is already premised on an understanding of others' knowledge and ignorance, along with a prosocial motive to help others by providing needed information.

title: Origins of human communication
abstract: Winner, 2009 Eleanor Maccoby Book Award in Developmental Psychology, presented by the American Psychological Association. and Honorable Mention, Literature, Language & Linguistics category, 2008 PROSE Awards presented by the Professional/Scholarly Publishing Division of the Association of American Publishers. Human communication is grounded in fundamentally cooperative, even shared, intentions. In this original and provocative account of the evolutionary origins of human communication, Michael Tomasello connects the fundamentally cooperative structure of human communication (initially discovered by Paul Grice) to the especially cooperative structure of human (as opposed to other primate) social interaction. Tomasello argues that human cooperative communication rests on a psychological infrastructure of shared intentionality (joint attention, common ground), evolved originally for collaboration and culture more generally. The basic motives of the infrastructure are helping and sharing: humans communicate to request help, inform others of things helpfully, and share attitudes as a way of bonding within the cultural group. These cooperative motives each created different functional pressures for conventionalizing grammatical constructions. Requesting help in the immediate you-and-me and here-and-now, for example, required very little grammar, but informing and sharing required increasingly complex grammatical devices. Drawing on empirical research into gestural and vocal communication by great apes and human infants (much of it conducted by his own research team), Tomasello argues further that humans' cooperative communication emerged first in the natural gestures of pointing and pantomiming. Conventional communication, first gestural and then vocal, evolved only after humans already possessed these natural gestures and their shared intentionality infrastructure along with skills of cultural learning for creating and passing along jointly understood communicative conventions. Challenging the Chomskian view that linguistic knowledge is innate, Tomasello proposes instead that the most fundamental aspects of uniquely human communication are biological adaptations for cooperative social interaction in general and that the purely linguistic dimensions of human communication are cultural conventions and constructions created by and passed along within particular cultural groups.

title: Differences in the nonverbal requests of great apes and human infants.
abstract: This study investigated how great apes and human infants use imperative pointing to request objects. In a series of three experiments (infants, N = 44; apes, N = 12), subjects were given the opportunity to either point to a desired object from a distance or else to approach closer and request it proximally. The apes always approached close to the object, signaling their request through instrumental actions. In contrast, the infants quite often stayed at a distance, directing the experimenters' attention to the desired object through index-finger pointing, even when the object was in the open and they could obtain it by themselves. Findings distinguish 12-month-olds' imperative pointing from ontogenetic and phylogenetic earlier forms of ritualized reaching.

title: One-year-olds comprehend the communicative intentions behind gestures in a hiding game.
abstract: This study explored infants' ability to infer communicative intent as expressed in non-linguistic gestures. Sixty children aged 14, 18 and 24 months participated. In the context of a hiding game, an adult indicated for the child the location of a hidden toy by giving a communicative cue: either pointing or ostensive gazing toward the container containing the toy. To succeed in this task children had to do more than just follow the point or gaze to the target container. They also had to infer that the adult's behaviour was relevant to the situation at hand - she wanted to inform them that the toy was inside the container toward which she gestured. Children at all three ages successfully used both types of cues. We conclude that infants as young as 14 months of age can, in some situations, interpret an adult behaviour as a relevant communicative act done for them.

title: Different social motives in the gestural communication of chimpanzees and human children.
abstract: Both chimpanzees and human infants use the pointing gesture with human adults, but it is not clear if they are doing so for the same social motives. In two studies, we presented chimpanzees and human 25-month-olds with the opportunity to point for a hidden tool (in the presence of a non-functional distractor). In one condition it was clear that the tool would be used to retrieve a reward for the pointing subject (so the pointing was selfish or 'for-me'), whereas in the other condition it was clear that the tool would be used to retrieve the reward for the experimenter (so the pointing was helpful or 'for-you'). The chimpanzees pointed reliably only when they themselves benefited, whereas the human children pointed reliably no matter who benefited. These results are interpreted as evidence for the especially cooperative nature of human communication.

title: Evidence and interpretation in great ape gestural communication
abstract: Tomasello and colleagues have offered various arguments to explain why apes find the comprehension of pointing difficult. They have argued that: (i) apes fail to understand communicative intentions; (ii) they fail to understand informative, cooperative communication, and (iii) they fail to track the common ground that pointing comprehension requires. In the course of a review of the literature on apes’ production and comprehension of pointing, I reject (i) and (ii), and offer a qualified defence of (iii). Drawing on work on expressive communication, I sketch an account of a mechanism by which ape gestural communication may proceed: the showing of expressive and naturally meaningful embodied behaviours. Such gestures are easily interpretable because they present rich evidence for a speaker’s message. By contrast, pointing typically provides poor evidence for a speaker’s message, which must therefore be inferred from considerations in the interlocutors’ common ground. This makes pointing comprehension comparatively difficult.

title: Pointing behaviors in apes and human infants: a balanced interpretation.
abstract: This article presents a tentatively "balanced" view (i.e., midway between lean and rich interpretations) of pointing behavior in infants and apes, based upon the notion of intentional reading of behavior without simultaneous attribution of unobservable mental states. This can account for the complexity of infant pointing without attributing multilayered mindreading to infants. It can also account for ape pointing, which shares some of the complexities of infant pointing, but departs from it in other respects, notably in its range of motives and its focus upon the regulation of executive behavior. The article explores some explanations for these similarities and differences and calls for a new look at human infant communication unbiased by adult communication models.

title: Teleological reasoning in infancy: the naı̈ve theory of rational action
abstract: Converging evidence demonstrates that one-year-olds interpret and draw inferences about other's goal-directed actions. We contrast alternative theories about how this early competence relates to our ability to attribute mental states to others. We propose that one-year-olds apply a non-mentalistic interpretational system, the 'teleological stance' to represent actions by relating relevant aspects of reality (action, goal-state and situational constraints) through the principle of rational action, which assumes that actions function to realize goal-states by the most efficient means available. We argue that this early inferential principle is identical to the rationality principle of the mentalistic stance - a representational system that develops later to guide inferences about mental states.

title: 'Obsessed with goals': functions and mechanisms of teleological interpretation of actions in humans.
abstract: Humans show a strong and early inclination to interpret observed behaviours of others as goal-directed actions. We identify two main epistemic functions that this 'teleological obsession' serves: on-line prediction and social learning. We show how teleological action interpretations can serve these functions by drawing on two kinds of inference ('action-to-goal' or 'goal-to-action'), and argue that both types of teleological inference constitute inverse problems that can only be solved by further assumptions. We pinpoint the assumptions that the three currently proposed mechanisms of goal attribution (action-effect associations, simulation procedures, and teleological reasoning) imply, and contrast them with the functions they are supposed to fulfil. We argue that while action-effect associations and simulation procedures are generally well suited to serve on-line action monitoring and prediction, social learning of new means actions and artefact functions requires the inferential productivity of teleological reasoning.

title: Natural pedagogy
abstract: We propose that human communication is specifically adapted to allow the transmission of generic knowledge between individuals. Such a communication system, which we call 'natural pedagogy', enables fast and efficient social learning of cognitively opaque cultural knowledge that would be hard to acquire relying on purely observational learning mechanisms alone. We argue that human infants are prepared to be at the receptive side of natural pedagogy (i) by being sensitive to ostensive signals that indicate that they are being addressed by communication, (ii) by developing referential expectations in ostensive contexts and (iii) by being biased to interpret ostensive-referential communication as conveying information that is kind-relevant and generalizable.

title: OBEYING SOCIAL RULES: A COMPARATIVE STUDY ON DOGS AND HUMANS*
abstract: Here we suggest that subjects' performance in a traditional object permanence paradigm could be based on the contribution of different cognitive capacities such as (1) the ability to repre- sent an object mentally in case of invisible displacements; (2) the ability to use appropriate deduc- tive inferences; (3) the ability to use associative learning and local rules or cues; and (4) the pres- ence of appropriate motivation to solve the task. In addition to these, there is another factor that may contribute to the performance, at least in some social species: (5) the ability to identify and use social rules that are formed by the interaction with the experimenter during the consecutive object hiding and search tasks. Experiment 1 was designed to demonstrate that such social rules may have an independent influence on the performance of both human and dog subjects during consecutive object hiding and search tasks. The behaviours of adult and preschool humans and adult pet dogs were compared in a modified version of the successive invisible displacements task (no object condition) and in a similar task in which, however, the location of the target object was well known by the subjects (game condition). During the no object condition most of the humans and dogs performed a full and systematic search of all potential hiding places. However, results in game condition indicate that Piagetian object permanence tests may be interpreted by both dogs and humans not only as object hiding and finding tasks, but, alternatively, as social-behavioural games of different sorts that may contribute to the systematic search performance. It seems that successful performance on such tasks should not be interpreted exclusively as indicating a representational understanding of object permanence and an ability for deductive inferences. A second experiment was directly designed to demonstrate the influential effect of social rules in the object hiding and finding tasks. Results show that the functional 'opacity' of the HIDER's behaviour (i.e., performing both functionally relevant and irrelevant actions upon hiding) enhanced the emergence of 'obeying social rules' (i.e., dogs tended to perform search behaviour, although they knew the location of the target object). We suggest that during their domestication dogs may have been selected for certain human-like capacities such as recognising and following social rules in the context of interacting with humans.

title: The dog as a model for understanding human social behavior
abstract: This chapter was originally published in the book Advances in The Study of Behavior, Vol. 39, published by Elsevier, and the attached copy is provided by Elsevier for the author's benefit and for the benefit of the author's institution, for non-commercial research and educational use including without limitation use in instruction at your institution, sending it to specific colleagues who know you, and providing a copy to your institution’s administrator.

title: Dogs, Canis familiaris, communicate with humans to request but not to inform
abstract: Dogs are especially skilful at comprehending human communicative signals. This raises the question of whether they are also able to produce such signals flexibly, specifically, whether they helpfully produce indicative (‘showing’) behaviours to inform an ignorant human. In experiment 1, dogs indicated the location of an object more frequently when it was something they wanted themselves than when it was something the human wanted. There was some suggestion that this might be different when the human was their owner. So in experiment 2 we investigated whether dogs could understand when the owner needed helpful information to find a particular object (out of two) that they needed. They did not. Our findings, therefore, do not support the hypothesis that dogs communicate with humans to inform them of things they do not know.

title: Species comparative studies and cognitive development
abstract: The comparative study of infant development and animal cognition brings to cognitive science the promise of insights into the nature and origins of cognitive skills. In this article, I review a recent wave of comparative studies conducted with similar methodologies and similar theoretical frameworks on how two core components of human cognition--object permanence and gaze following--develop in different species. These comparative findings call for an integration of current competing accounts of developmental change. They further suggest that evolution has produced developmental devices capable at the same time of preserving core adaptive components, and opening themselves up to further adaptive change, not only in interaction with the external environment, but also in interaction with other co-developing cognitive systems.

title: Do dogs distinguish rational from irrational acts?
abstract: Range et al. (2007, Current Biology, 17, 868–872) found that dogs, Canis familiaris, copy others’ means to achieve a goal more often when those means are the rational solution to a problem than when they are irrational. In our first experiment, we added a further control condition and failed to replicate this result, suggesting that dogs in the previous study may have been distracted in the irrational condition rather than selectively attending to the irrational nature of the action. In a second experiment, the demonstrator used an unusual means (an extended leg) to communicate the location of food, either rationally (her hands were occupied) or irrationally (she could have used her hand). Dogs succeeded in finding the food irrespective of whether the leg action was rational or irrational. Our results suggest that dogs do not distinguish rational from irrational acts, instead simply being proficient at monitoring human behavioural patterns.

title: A nonverbal test of knowledge attribution: a comparative study on dogs and children
abstract: The sensitivity of eleven pet dogs and eleven 2.5-year-old children to others’ past perceptual access was tested for object-specificity in a playful, nonverbal task in which a human Helper’s knowledge state regarding the whereabouts of a hidden toy and a stick (a tool necessary for getting the out-of-reach toy) was systematically manipulated. In the four experimental conditions the Helper either participated or was absent during hiding of the toy and the stick and therefore she knew the place(s) of (1) both the toy and the stick, (2) only the toy, (3) only the stick or (4) neither of them. The subjects observed the hiding processes, but they could not reach the objects, so they had to involve the Helper to retrieve the toy. The dogs were more inclined to signal the place of the toy in each condition and indicated the location of the stick only sporadically. However the children signalled both the location of the toy and that of the stick in those situations when the Helper had similar knowledge regarding the whereabouts of them (i.e. knew or ignored both of them), and in those conditions in which the Helper was ignorant of the whereabouts of only one object the children indicated the place of this object more often than that of the known one. At the same time however, both dogs and children signalled the place of the toy more frequently if the Helper had been absent during toy-hiding compared to those conditions when she had participated in the hiding. Although this behaviour appears to correspond with the Helper’s knowledge state, even the subtle distinction made by the children can be interpreted without a casual understanding of knowledge-formation in others.

title: The measurement of observer agreement for categorical data.
abstract: This paper presents a general statistical methodology for the analysis of multivariate categorical data arising from observer reliability studies. The procedure essentially involves the construction of functions of the observed proportions which are directed at the extent to which the observers agree among themselves and the construction of test statistics for hypotheses involving these functions. Tests for interobserver bias are presented in terms of first-order marginal homogeneity and measures of interobserver agreement are developed as generalized kappa-type statistics. These procedures are illustrated with a clinical diagnosis example from the epidemiological literature.

title: Fitting Linear Mixed-Effects Models Using lme4
abstract: Maximum likelihood or restricted maximum likelihood (REML) estimates of the parameters in linear mixed-effects models can be determined using the lmer function in the lme4 package for R. As for most model-fitting functions in R, the model is described in an lmer call by a formula, in this case including both fixed- and random-effects terms. The formula and data together determine a numerical representation of the model from which the profiled deviance or the profiled REML criterion can be evaluated as a function of some of the model parameters. The appropriate criterion is optimized, using one of the constrained optimization functions in R, to provide the parameter estimates. We describe the structure of the model, the steps in evaluating the profiled deviance or REML criterion, and the structure of classes or types that represents such a model. Sufficient detail is included to allow specialization of these structures by users who wish to write functions to fit specialized linear mixed models, such as models incorporating pedigrees or smoothing splines, that are not easily expressible in the formula language used by lmer.

title: Model selection and multimodel inference : a practical information-theoretic approach
abstract: The second edition of this book is unique in that it focuses on methods for making formal statistical inference from all the models in an a priori set (Multi-Model Inference). A philosophy is presented for model-based data analysis and a general strategy outlined for the analysis of empirical data. The book invites increased attention on a priori science hypotheses and modeling. Kullback-Leibler Information represents a fundamental quantity in science and is Hirotugu Akaike's basis for model selection. The maximized log-likelihood function can be bias-corrected as an estimator of expected, relative Kullback-Leibler information. This leads to Akaike's Information Criterion (AIC) and various extensions. These methods are relatively simple and easy to use in practice, but based on deep statistical theory. The information theoretic approaches provide a unified and rigorous theory, an extension of likelihood theory, an important application of information theory, and are objective and practical to employ across a very wide class of empirical problems. The book presents several new ways to incorporate model selection uncertainty into parameter estimates and estimates of precision. An array of challenging examples is given to illustrate various technical issues. This is an applied book written primarily for biologists and statisticians wanting to make inferences from multiple models and is suitable as a graduate text or as a reference for professional analysts.

title: Domestic dogs (Canis familiaris) are sensitive to the attentional state of humans.
abstract: Twelve domestic dogs (Canis familiaris) were given a series of trials in which they were forbidden to take a piece of visible food. In some trials, the human continued to look at the dog throughout the trial (control condition), whereas in others, the human (a) left the room, (b) turned her back, (c) engaged in a distracting activity, or (d) closed her eyes. Dogs behaved in clearly different ways in most of the conditions in which the human did not watch them compared with the control condition, in which she did. In particular, when the human looked at them, dogs retrieved less food, approached it in a more indirect way, and sat (as opposed to laid down) more often than in the other conditions. Results are discussed in terms of domestic dogs' social-cognitive skills and their unique evolutionary and ontogenetic histories.

title: How dogs know when communication is intended for them.
abstract: Domestic dogs comprehend human gestural communication in a way that other animal species do not. But little is known about the specific cues they use to determine when human communication is intended for them. In a series of four studies, we confronted both adult dogs and young dog puppies with object choice tasks in which a human indicated one of two opaque cups by either pointing to it or gazing at it. We varied whether the communicator made eye contact with the dog in association with the gesture (or whether her back was turned or her eyes were directed at another recipient) and whether the communicator called the dog's name (or the name of another recipient). Results demonstrated the importance of eye contact in human-dog communication, and, to a lesser extent, the calling of the dog's name--with no difference between adult dogs and young puppies--which are precisely the communicative cues used by human infants for identifying communicative intent. Unlike human children, however, dogs did not seem to comprehend the human's communicative gesture when it was directed to another human, perhaps because dogs view all human communicative acts as directives for the recipient.

title: Dogs respond appropriately to cues of humans’ attentional focus
abstract: Dogs' ability to recognise cues of human visual attention was studied in different experiments. Study 1 was designed to test the dogs' responsiveness to their owner's tape-recorded verbal commands (Down!) while the Instructor (who was the owner of the dog) was facing either the dog or a human partner or none of them, or was visually separated from the dog. Results show that dogs were more ready to follow the command if the Instructor attended them during instruction compared to situations when the Instructor faced the human partner or was out of sight of the dog. Importantly, however, dogs showed intermediate performance when the Instructor was orienting into 'empty space' during the re-played verbal commands. This suggests that dogs are able to differentiate the focus of human attention. In Study 2 the same dogs were offered the possibility to beg for food from two unfamiliar humans whose visual attention (i.e. facing the dog or turning away) was systematically varied. The dogs' preference for choosing the attentive person shows that dogs are capable of using visual cues of attention to evaluate the human actors' responsiveness to solicit food-sharing. The dogs' ability to understand the communicatory nature of the situations is discussed in terms of their social cognitive skills and unique evolutionary history.

title: Beyond rational imitation: learning arbitrary means actions from communicative demonstrations.
abstract: The principle of rationality has been invoked to explain that infants expect agents to perform the most efficient means action to attain a goal. It has also been demonstrated that infants take into account the efficiency of observed actions to achieve a goal outcome when deciding whether to reenact a specific behavior or not. It is puzzling, however, that they also tend to imitate an apparently suboptimal unfamiliar action even when they can bring about the same outcome more efficiently by applying a more rational action alternative available to them. We propose that this apparently paradoxical behavior is explained by infants' interpretation of action demonstrations as communicative manifestations of novel and culturally relevant means actions to be acquired, and we present empirical evidence supporting this proposal. In Experiment 1, we found that 14-month-olds reenacted novel arbitrary means actions only following a communicative demonstration. Experiment 2 showed that infants' inclination to reproduce communicatively manifested novel actions is restricted to behaviors they can construe as goal-directed instrumental acts. The study also provides evidence that infants' reenactment of the demonstrated novel actions reflects epistemic motives rather than purely social motives. We argue that ostensive communication enables infants to represent the teleological structure of novel actions even when the causal relations between means and end are cognitively opaque and apparently violate the efficiency expectation derived from the principle of rationality. This new account of imitative learning of novel means shows how the teleological stance and natural pedagogy--two separate cognitive adaptations to interpret instrumental versus communicative actions--are integrated as a system for learning socially constituted instrumental knowledge in humans.

title: Neophilia in domestic dogs (Canis familiaris) and its implication for studies of dog cognition
abstract: This study examined novel-object preference in dogs. In a free choice test 17 dogs were presented with a novel toy in a line up with two familiar toys. The unfamiliar object was chosen first in 38 out 50 tests suggesting a strong preference for novel over familiar items. Neophilia may be an adaptive trait for domestic dogs that has helped their adaptation towards man.

title: Acoustic structure and receiver response in domestic dogs, Canis familiaris

abstract: The hypothesis that short, rapidly repeated rising notes increase motor activity levels in canids, and that longer, continuous descending notes decrease activity was tested. Young laboratory-raised domestic dogs were trained in a repeated measures study to (1) come to the trainer and to (2) sit and stay for 2 s to two different acoustic stimuli: four short notes with a rising fundamental frequency and one long note with a descending fundamental frequency. While one long note was not more effective at eliciting a sit/stay response, four short notes were more effective at eliciting a come response and increasing motor activity levels than one longer continuous note. Thus, acoustic stimuli are not equipotent in eliciting responses that require changes in motor activity levels and could be used by signal senders to influence the behaviour of the signal receiver. The acoustic structures in the study are compared with vocalizations of mammals and birds that elicit approach, and/or increase motor activity levels.

title: The order of ostensive and referential signals affects dogs’ responsiveness when interacting with a human
abstract: Ostensive signals preceding referential cues are crucial in communication-based human knowledge acquisition processes. Since dogs are sensitive to both human ostensive and referential signals, here we investigate whether they also take into account the order of these signals and, in an object-choice task, respond to human pointing more readily when it is preceded by an ostensive cue indicating communicative intent. Adult pet dogs (n = 75) of different breeds were presented with different sequences of a three-step human action. In the relevant sequence (RS) condition, subjects were presented with an ostensive attention getter (verbal addressing and eye contact), followed by referential pointing at one of two identical targets and then a non-ostensive attention getter (clapping of hands). In the irrelevant sequence (IS) condition, the order of attention getters was swapped. We found that dogs chose the target indicated by pointing more frequently in the RS as compared to the IS condition. While dogs selected randomly between the target locations in the IS condition, they performed significantly better than chance in the RS condition. Based on a further control experiment (n = 22), it seems that this effect is not driven by the aversive or irrelevant nature of the non-ostensive cue. This suggests that dogs are sensitive to the order of signal sequences, and the exploitation of human referential pointing depends on the behaviour pattern in which the informing cue is embedded.

title: Owners’ direct gazes increase dogs’ attention-getting behaviors
abstract: This study examined whether dogs gain information about human's attention via their gazes and whether they change their attention-getting behaviors (i.e., whining and whimpering, looking at their owners' faces, pawing, and approaching their owners) in response to their owners' direct gazes. The results showed that when the owners gazed at their dogs, the durations of whining and whimpering and looking at the owners' faces were longer than when the owners averted their gazes. In contrast, there were no differences in duration of pawing and likelihood of approaching the owners between the direct and averted gaze conditions. Therefore, owners' direct gazes increased the behaviors that acted as distant signals and did not necessarily involve touching the owners. We suggest that dogs are sensitive to human gazes, and this sensitivity may act as attachment signals to humans, and may contribute to close relationships between humans and dogs.

title: The environment and disease: association or causation?
abstract: Among the objects of this newly founded Section of Occupational Medicine are: first, ‘to provide a means, not readily afforded elsewhere, whereby physicians and surgeons with a special knowledge of the relationship between sickness and injury and conditions of work may discuss their problems, not only with each other, but also with colleagues in other fields, by holding joint meetings with other Sections of the Society’; and second, ‘to make available information about the physical, chemical and psychological hazards of occupation, and in particular about those that are rare or not easily recognized’. At this first meeting of the Section and before, with however laudable intentions, we set about instructing our colleagues in other fields, it will be proper to consider a problem fundamental to our own. How in the first place do we detect these relationships between sickness, injury and conditions of work? How do we determine what are physical, chemical and psychological hazards of occupation, and in particular those that are rare and not easily recognised? There are, of course, instances in which we can reasonably answer these questions from the general body of medical knowledge. A particular, and perhaps extreme, physical environment cannot fail to be harmful; a particular chemical is known to be toxic to man and therefore suspect on the factory floor. Sometimes, alternatively, we may be able to consider what might a particular environment do to man, and then see whether such consequences are indeed to be found. But more often than not we have no such guidance, no such means of proceeding; more often than not we are dependent upon our observation and enumeration of defined events for which we then seek antecedents. In other words, we see that the event B is associated with the environmental feature A, that, to take a specific example, some form of respiratory illness is associated with a dust in the environment. In what circumstances can we pass from this observed association to a verdict of causation? Upon what basis should we proceed to do so? I have no wish, nor the skill, to embark upon a philosophical discussion of the meaning of ‘causation’. The ‘cause’ of illness may be immediate and direct, it may be remote and indirect underlying the observed association. But with the aims of occupational, and almost synonymously preventive, medicine in mind, the decisive question is whether the frequency of the undesirable event B will be influenced by a change in the environmental feature A. How such a change exerts that influence may call for a great deal of research. However, before deducing ‘causation’ and taking action, we shall not invariably have to sit around awaiting the results of that research. The whole chain may have to be unravelled or a few links may suffice. It will depend upon circumstances. Disregarding then any such problem in semantics we have this situation. Our observations reveal an association between two variables, perfectly clearcut and beyond what we would care to attribute to the play of chance. What aspects of that association should we especially consider before deciding that the most likely interpretation of it is causation?

title: Functionally referential and intentional communication in the domestic dog: effects of spatial and social contexts
abstract: In apes, four criteria are set to explore referential and intentional communication: (1) successive visual orienting between a partner and distant targets, (2) the presence of apparent attention-getting behaviours, (3) the requirement of an audience to exhibit the behaviours, and (4) the influence of the direction of attention of an observer on the behaviours. The present study aimed at identifying these criteria in behaviours used by dogs in communicative episodes with their owner when their toy is out of reach, i.e. gaze at a hidden target or at the owner, gaze alternation between a hidden target and the owner, vocalisations and contacts. In this study, an additional variable was analysed: the position of the dog in relation to the location of the target. Dogs witnessed the hiding of a favourite toy, in a place where they could not get access to. We analysed how dogs engaged in communicative deictic behaviours in the presence of their owner; four heights of the target were tested. To control for the motivational effects of the toy on the dogs’ behaviour and for the referential nature of the behaviours, observations were staged where only the toy or only the owner was present, for one of the four heights. The results show that gazing at the container and gaze alternation were used as functionally referential and intentional communicative behaviours. Behavioural patterns of dog position, the new variable, fulfilled the operational criteria for functionally referential behaviour and a subset of operational criteria for intentional communication: the dogs used their own position as a local enhancement signal. Finally, our results suggest that the dogs gazed at their owner at optimal locations in the experimental area, with respect to the target height and their owner’s (or their own) line of gaze.

title: Clever hounds: social cognition in the domestic dog (Canis familiaris)
abstract: This paper reviews the reasons why domestic dogs make good models to investigate cognitive processes related to social living and describes experimental approaches that can be adopted to investigate such processes in dogs. Domestic dogs are suitable models for investigating social cognition skills for three broad reasons. First, dogs originated from wolves, social animals that engage in a number of co-operative behaviours, such as hunting and that may have evolved cognitive abilities that help them predict and interpret the actions of other animals. Second, during domestication dogs are likely to have been selected for mental adaptations for their roles in human society such as herding or companionship. Third, domestic dogs live in a human world and “enculturation” may facilitate the development of relevant mental skills in dogs. Studies of social cognition in animals commonly use experimental paradigms originally developed for pre-verbal human infants. Preferential gaze, for example, can be used as a measure of attention or “surprise” in studies using expectancy violation. This approach has been used to demonstrate simple numerical competence in dogs. Dogs also readily use both conspecific and human social signals (e.g. looking or pointing) as information sources to locate hidden rewards such as food or favourite toys. Such abilities make dogs particularly good models for investigating perspective-taking tasks, where animals are required to discriminate between apparently knowledgeable and apparently ignorant informants.

title: When do dogs help humans
abstract: a b s t r a c t Here we investigate whether domestic dogs (Canis familiaris) engage in instrumental helping towards humans without special training. We hypothesized that dogs would help a human if the human’s goal was made as obvious as possible. Therefore we used a set-up in which a human attempted to enter a compartment within a room (the “target room”) in order to get a key. The dog could open the door to the target room by pushing a button. We varied the way in which the experimenter expressed how she wanted to enter the target room (reaching, pushing the door, communicating with the dog) and the relationship between human and dog (owner versus stranger). Dogs helped in two situations: (1) when the human pointed at the button and (2) when the humans communicated naturally to the dogs, i.e. without a predetermined series of actions. In these situations, dogs continued to open the door without receiving any reward. We therefore conclude that dogs are motivated to help and that an experimenter’s natural behaviours facilitated the dogs’ recognition of the human’s goal. Interestingly the identity of the experimenter had no influence on the behaviour of the dogs.

title: Behavioural coordination of dogs in a cooperative problem-solving task with a conspecific and a human partner
abstract: The process of domestication has arguably provided dogs (Canis familiaris) with decreased emotional reactivity (reduced fear and aggression) and increased socio-cognitive skills adaptive for living with humans. It has been suggested that dogs are uniquely equipped with abilities that have been identified as crucial in cooperative problem-solving, namely social tolerance and the ability to attend to other individuals’ behaviour. Accordingly, dogs might be hypothesised to perform well in tasks in which they have to work together with a human partner. Recently, researchers have found that dogs successfully solved a simple cooperative task with another dog. Due to the simplicity of the task, this study was, however, unable to provide clear evidence as to whether the dogs’ successful performance was based on the cognitive ability of behavioural coordination, namely the capacity to link task requirements to the necessity of adjusting one’s actions to the partner’s behaviour. Here, we tested dogs with the most commonly used cooperative task, appropriate to test behavioural coordination. In addition, we paired dogs with both a conspecific and a human partner. Although dogs had difficulties in inhibiting the necessary action when required to wait for their partner, they successfully attended to the two cues that predicted a successful outcome, namely their partner’s behaviour and the incremental movement of rewards towards themselves. This behavioural coordination was shown with both a conspecific and a human partner, in line with the recent findings suggesting that dogs exhibit highly developed socio-cognitive skills in interactions with both humans and other dogs.

title: Co-operative interactions between blind persons and their dogs
abstract: In two studies, we have investigated the co-operative behaviour between dogs and their owners. We supposed that co-operative behaviour is an inherited trait in dogs, and is a major contributing factor in the development of successful guide dog performance. According to our view, leading a blind person involves complex behaviour where success depends on the ability of the participants to synchronise their actions. In Study I, we observed both British and Hungarian blind owners taking a half-hour walk in their neighbourhood. In Study II, both guide dogs with their blind and pet dogs with their blind-folded owners had to master an obstacle course. Measuring the frequency of initiations of various actions during leading their owners, dogs did not keep the role of the initiator to themselves. However, both dogs and humans were found to initiate more often in some types of actions, for example, guide dogs initialised avoidance or stepping up more often than their owners. Further, the role of the initiator was kept only for short durations, longer sequences of initialising were rare. Despite many differences among groups studied, we observed some qualitative similarities in the co-operative behaviour of dogs. We assume that during domestication, dogs have been selected for the ability to change to-and-fro the role of the initiator that seems to be fundamental in this type of co-operation. In the case of leading the blind, information should not only be provided but also accepted by both parties in the course of the joint actions, therefore, the leadership (the role of the initiator) may vary form one action to the next.

title: Does dog-human attachment affect their inter-specific cooperation?
abstract: Leading a blind or blindfolded person is a complex cooperative task influenced by many factors. The aim of this study was to determine if quality of attachment affects the performance of dog and owner dyads showed on an Obstacle Course. Modified Ainsworth's Strange Situation Test was used for assessing attachment quality. Only one dimension of the attachment, the 'anxiety' factor was found to correlate with behavioural measures of the Obstacle Course (e.g. number of mistakes, initialisation index that reflects which participant initiates more actions in a dyad). We found significant differences of performance between the three groups of dog-owner pairs (pet dog, guide dog and police dog dyads), but we could not show significant differences in the 'attachment' factor among these groups. We concluded that it is not the attachment type that causes the main differences in the leading behaviour of our three study groups. Dogs have an innate ability for cooperation with humans that was enhanced by selective breeding during domestication and this basic ability can be modified by training but seem to be less affected by the relationship with the owner.

title: Do Domestic Dogs Learn Words Based on Humans’ Referential Behaviour?
abstract: Some domestic dogs learn to comprehend human words, although the nature and basis of this learning is unknown. In the studies presented here we investigated whether dogs learn words through an understanding of referential actions by humans rather than simple association. In three studies, each modelled on a study conducted with human infants, we confronted four word-experienced dogs with situations involving no spatial-temporal contiguity between the word and the referent; the only available cues were referential actions displaced in time from exposure to their referents. We found that no dogs were able to reliably link an object with a label based on social-pragmatic cues alone in all the tests. However, one dog did show skills in some tests, possibly indicating an ability to learn based on social-pragmatic cues.