Perspektiven von Mensch-Hund-Interaktionen

In comparative psychology we draw inferences about the evolution of cognition by investigating the similarities and differences between human and non-human animals. I am especially interested in which cognitive skills have evolved in different species that allow them to be optimally adapted to their environment. Dogs, due to their high sociality and the fact that they were subject to a special domestication process, represent a highly promising model to investigate social cognition from a comparative perspective. Studying dog cognition not only sheds light on the question on what skills humans share with other animal species, but also what kind of selection pressures lead to human-like skills. Dogs are not simply pets that live in the human environment, but they also form a close relationship to humans and cooperate with them. Thus, studying dogs living in that special niche will not only inform us about their cognitive skills but might also help us to better understand the selection pressures that led to the unique cognition of humans. The aim of this habilitation thesis is to characterize the dog-human relationship taking diverse perspectives on dog cognition and the dog-human bond. During their long domestication process, dogs have evolved special cognitive skills that help them to function effectively in human societies. In this thesis, I present experimental evidence for these skills and I suggest that the skills have evolved in a domain-specific manner, independently from each other. Dogs show outstanding cognitive skills in the domain of (1.) communication, (2.) perspective taking, (3.) cooperation and (4.) olfaction processing, but perform poorly or average in other domains such as (5.) metacognition and (6.) behavioral matching. Regarding (1.) communication I present experimental evidence that dogs without special training are able to successfully show a human a hidden object and that this showing behavior in dogs is a means to communicate the location of that hidden object. I argue that successful communication between dog and humans in general is the consequence of four preconditions in dogs: (i) they are extremely attentive and interested in what humans are doing, (ii) they have excellent learning abilities, (iii) they are able to read subtle cues of human behavior and (iv) they have extensive experience with different communicative situations. Furthermore, I present an experiment about (2.) perspective taking – defined as the ability to assess what others can perceive. Here I found that dogs are able conceal auditory but not visual information from humans when they approach forbidden food. Taken together with findings from previous studies, I conclude that dogs use certain strategies when they assess what a human can and cannot perceive. I studied (3.) cooperation both within dogs and between dogs and humans. Within dogs I used a problem-solving paradigm that involved aspects of a hunting-like situation. I compared the performances of dogs with those of wolves. My results suggest that the abilities needed to coordinate their actions were already present in the dog-wolf ancestor. Dogs and wolves may show similar cooperative skills when cooperating with their conspecifics, but dogs might cooperate better with humans than wolves do, as it is likely that during the domestication process dogs have been selected to cooperate specifically with humans. Consequently, I investigated the cognitive and motivational skills required for a dog to support a human. From the results I conclude that dogs display a number of prosocial behaviors towards a human when they are able to infer the goal of the human and when they understand how to fullfill it. In contrast to communicative, cooperative and perspective taking skills, (4.) the special olfactory skills of dogs probably did not evolve during domestication, but could be one of the reasons why dogs were domesticated. Here I present evidence that dogs can use olfactory information in an adaptable way: Dogs were presented with a violation-of-expectation paradigm in which they could track the odor trail of one target, but at the end of the trail, they found another target. I found that they are able to represent what they smell—that is, when they follow a trail they have an expectation of something or someone at the end of the trail. Thus, not only is dogs’ sense of smell itself quite outstanding, but so are also their related cognitive skills. In contrast, in their (5.) metacognitive skills and in (6.) behavioral matching, dogs do not show unique skills but perform similarly to other social mammals. Regarding (5.) metacognition I investigated whether dogs were sensitive to the information that they themselves had or had not acquired. I found that dogs seek additional information in uncertain situations, but their behavior in these situations is less flexible compared to great apes or human children. Finally, I did not find evidence for (6.) behavioral matching, ie. whether dogs develop an increased affiliation towards a human who mimics them. Dogs in my study showed no increased preference for one of two human experimenter who matched the dogs’ walk. In this thesis I present a view on dog cognition that differentiates individual cognitive skills, pointing out how exactly they are adapted to their special human environment. Thus, I emphasize the unique closeness of the dog-human relationship. I also point out where current findings are incomplete or show limits of their paradigms and call for further research. Firstly, I criticize the fact that most data on dogs’ understanding of their social and physical environment is based on performance in the visual or sometimes in the auditory modality. As dogs’ olfaction is their most relevant sense, I therefore call for more dog studies that are based on olfaction. Secondly, regarding the dog-human relationship, there are many open questions that have not yet been considered well enough: for example, whether dogs are capable of skills like empathy, the human perspective on dogs, and cultural differences in dog-human interactions. Thirdly, to better understand the dog-human bond it is crucial to further investigate when, where and how domestication started. This is also needed in order to understand why dogs were domesticated and what made and makes them valuable for humans. To answer the above mentioned questions, an interdisciplinary approach is crucial, in which scientists from the fields of archaeology, linguistics, paleoclimatology, genetics, anatomy, ethology, psychology, sociology, and anthropology work together

Fake or not: Two prerequisites for jealousy

Cook and colleagues (2018) use a novel approach to test jealousy in dogs. Although such a non-invasive approach is more than welcome in comparative research, several methodological shortcomings limit the impact of this study. We briefly outline two main problems. (1) There is no evidence that the fake dogs in the study were perceived as real, and thus as social rivals, which would be a prerequisite for jealousy. (2) It is questionable whether dogs generally show the cognitive prerequisites for jealousy, such as attentiveness toward a social rival, the ability to understand intentions, and a sense of fairness. We suggest that future studies should combine the same creativity with more controlled procedures in order to better understand the evolutionary origins of jealousy

The dissonance between knowing animals are sentient beings yet eating them

Animal sentience is linked to the bigger picture of climate and health crises and “carnism” is a factor in the dissonance among (1) knowing animals are sentient, (2) caring about their feelings, and (3) not acting accordingly. We discuss our responsibility as researchers and as individual human beings

The effects of domestication and ontogeny on cognition in dogs and wolves

Abstract Cognition is one of the most flexible tools enabling adaptation to environmental variation. Living close to humans is thought to influence social as well as physical cognition of animals throughout domestication and ontogeny. Here, we investigated to what extent physical cognition and two domains of social cognition of dogs have been affected by domestication and ontogeny. To address the effects of domestication, we compared captive wolves (n = 12) and dogs (n = 14) living in packs under the same conditions. To explore developmental effects, we compared these dogs to pet dogs (n = 12) living in human families. The animals were faced with a series of object-choice tasks, in which their response to communicative, behavioural and causal cues was tested. We observed that wolves outperformed dogs in their ability to follow causal cues, suggesting that domestication altered specific skills relating to this domain, whereas developmental effects had surprisingly no influence. All three groups performed similarly in the communicative and behavioural conditions, suggesting higher ontogenetic flexibility in the two social domains. These differences across cognitive domains need to be further investigated, by comparing domestic and non-domesticated animals living in varying conditions

Communicating canine and human emotions

Kujala (2017) reviews a topic of major relevance for the understanding of the special dog-human relationship: canine emotions (as seen through human social cognition). This commentary draws attention to the communication of emotions within such a particular social context. It highlights challenges that need to be tackled to further advance research on emotional communication, and it calls for new avenues of research. Efforts to disentangle emotional processes from cognitive functioning might be necessary to better comprehend how they contribute, alone and/or in combination, to the communication of emotions. Also, new research methods need to be developed to account for the rich sensory repertoire of dogs, likely involved in emotional communication

Chimpanzees do not take into account what others can hear in a competitive situation

Chimpanzees (Pan troglodytes) know what others can and cannot see in a competitive situation. Does this reflect a general understanding the perceptions of others? In a study by Hare et al. (2000) pairs of chimpanzees competed over two pieces of food. Subordinate individuals preferred to approach food that was behind a barrier that the dominant could not see, suggesting that chimpanzees can take the visual perspective of others. We extended this paradigm to the auditory modality to investigate whether chimpanzees are sensitive to whether a competitor can hear food rewards being hidden. Results suggested that the chimpanzees did not take what the competitor had heard into account, despite being able to locate the hiding place themselves by the noise

Dogs (Canis familiaris), but Not Chimpanzees (Pan troglodytes), Understand Imperative Pointing

Chimpanzees routinely follow the gaze of humans to outside targets. However, in most studies using object choice they fail to use communicative gestures (e.g. pointing) to find hidden food. Chimpanzees' failure to do this may be due to several difficulties with this paradigm. They may, for example, misinterpret the gesture as referring to the opaque cup instead of the hidden food. Or perhaps they do not understand informative communicative intentions. In contrast, dogs seem to be skilful in using human communicative cues in the context of finding food, but as of yet there is not much data showing whether they also use pointing in the context of finding non-food objects. Here we directly compare chimpanzees' (N = 20) and dogs' (N = 32) skills in using a communicative gesture directed at a visible object out of reach of the human but within reach of the subject. Pairs of objects were placed in view of and behind the subjects. The task was to retrieve the object the experimenter wanted. To indicate which one she desired, the experimenter pointed imperatively to it and directly rewarded the subject for handing over the correct one. While dogs performed well on this task, chimpanzees failed to identify the referent. Implications for great apes' and dogs' understanding of human communicative intentions are discussed

Comparing dogs and great apes in their ability to visually track object transpositions

Knowing that objects continue to exist after disappearing from sight and tracking invisible object displacements are two basic elements of spatial cognition. The current study compares dogs and apes in an invisible transposition task. Food was hidden under one of two cups in full view of the subject. After that both cups were displaced, systematically varying two main factors, whether cups were crossed during displacement and whether the cups were substituted by the other cup or instead cups were moved to new locations. While the apes were successful in all conditions, the dogs had a strong preference to approach the location where they last saw the reward, especially if this location remained filled. In addition, dogs seem to have especial difficulties to track the reward when both containers crossed their path during displacement. These results confirm the substantial difference that exists between great apes and dogs with regard to mental representation abilities required to track the invisible displacements of objects