Dog-human social relationship: representation of human face familiarity and emotions in the dog brain.

This study investigated the behavioral and neural indices of detecting facial familiarity and facial emotions in human faces by dogs. Awake canine fMRI was used to evaluate dogs' neural response to pictures and videos of familiar and unfamiliar human faces, which contained positive, neutral, and negative emotional expressions. The dog-human relationship was behaviorally characterized out-of-scanner using an unsolvable task. The caudate, hippocampus, and amygdala, mainly implicated in reward, familiarity and emotion processing, respectively, were activated in dogs when viewing familiar and emotionally salient human faces. Further, the magnitude of activation in these regions correlated with the duration for which dogs showed human-oriented behavior towards a familiar (as opposed to unfamiliar) person in the unsolvable task. These findings provide a bio-behavioral basis for the underlying markers and functions of human-dog interaction as they relate to familiarity and emotion in human faces.

Comparing pet and detection dogs (Canis familiaris) on two aspects of social cognition.

Interspecific communication between dogs and humans enables dogs to occupy significant roles in human society, both in companion and working roles. Dogs excel at using human communicative signals in problem-solving tasks, and solicit human contact when unable to solve a problem. Dogs' sociocognitive behavior likely results from a selection for attention to humans during domestication, but is highly susceptible to environmental factors. Training for particular tasks appears to enhance dog-human communication, but effects may depend on the nature of the relationship determined by their role. Our aim was to examine two types of social cognition (responsiveness to human gestures, and human-directed communicative behavior in an unsolvable task) in pet dogs (n = 29) and detection dogs (n = 35). The groups did not differ in their ability to follow human signals, but pets were less responsive to signals given by a stranger than by their owner. Pets also exhibited more human-directed gazing in the unsolvable task, showing a bias for gazing at their owner compared with the stranger, whereas detection dogs showed greater persistence in attempting to solve the task compared with pets. Thus, different aspects of dogs' sociocognitive behavior may differentially vary as a function of selection or training for particular roles.

Separate brain areas for processing human and dog faces as revealed by awake fMRI in dogs (Canis familiaris).

Functional magnetic resonance imaging (fMRI) has emerged as a viable method to study the neural processing underlying cognition in awake dogs. Working dogs were presented with pictures of dog and human faces. The human faces varied in familiarity (familiar trainers and unfamiliar individuals) and emotional valence (negative, neutral, and positive). Dog faces were familiar (kennel mates) or unfamiliar. The findings revealed adjacent but separate brain areas in the left temporal cortex for processing human and dog faces in the dog brain. The human face area (HFA) and dog face area (DFA) were both parametrically modulated by valence indicating emotion was not the basis for the separation. The HFA and DFA were not influenced by familiarity. Using resting state fMRI data, functional connectivity networks (connectivity fingerprints) were compared and matched across dogs and humans. These network analyses found that the HFA mapped onto the human fusiform area and the DFA mapped onto the human superior temporal gyrus, both core areas in the human face processing system. The findings provide insight into the evolution of face processing.

Paradoxical gender effects in meat consumption across cultures.

Men tend to eat more meat than women, but it is not clear why. We tested three hypotheses in a cross-cultural design (20,802 individuals in 23 countries across four continents): that gender differences are (a) universal, (b) related to gender roles and thus weaker in countries with higher gender equality and human development, or (c) related to opportunities to express gender roles and thus stronger in countries with higher gender equality and human development. Across all countries, men tended to consume more meat than women. However, this difference increased significantly in countries with greater human development and gender equality. The paradoxical gender gap in meat consumption aligns with previous research that suggests greater differences in behavior across genders in contexts that are more developed and gender equal. We discuss implications for theories of culture and gender as well as practical implications for global meat reduction.

Neurofunctional correlates of geometry and feature use in a virtual environment.

There are mixed results regarding the differentiation of neurofunctional correlates of spatial abilities. Previous studies employed complex environments or alternate memory tasks which could potentially add to inconsistencies across studies of navigation. To help elucidate the existing mixed findings, we conducted a study in a simplistic environment without a supplemental memory task in order to examine navigationally relevant neural function using fMRI. Participants completed a virtual navigation task where they learned the relationship between landmarks, environmental features, and a goal. The goal was a distinct landmark, or feature, consistently situated in one corner, or a geometric cue, of a rectangular room. Test trials varied the relationship of featural and geometric cues allowing insight into navigational strategies when using these cues and when the cues are in conflict. Behavioral results showed participants learned the task rapidly and utilized both landmark feature-based and environmental geometry-based strategies to locate the goal; preferring the feature-based strategy. Neuroimaging results provided evidence for activation in navigationally relevant regions, including the parahippocampus, caudate, and retrosplenial cortex. These results demonstrate the importance of these structures and their relation to environmental geometry and feature use while navigating an enclosed simplistic environment. The results provide clarification regarding the role of the parahippocampus and caudate when using geometric- or landmark-based strategies and demonstrate the prerequisite of environmental novelty to elicit hippocampal activation. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Functional Magnetic Resonance Imaging of the Domestic Dog: Research, Methodology, and Conceptual Issues.

Neuroimaging of the domestic dog is a rapidly expanding research topic in terms of the cognitive domains being investigated. Because dogs have shared both a physical and social world with humans for thousands of years, they provide a unique and socially relevant means of investigating a variety of shared human and canine psychological phenomena. Additionally, their trainability allows for neuroimaging to be carried out noninvasively in an awake and unrestrained state. In this review, a brief overview of functional magnetic resonance imaging (fMRI) is followed by an analysis of recent research with dogs using fMRI. Methodological and conceptual concerns found across multiple studies are raised, and solutions to these issues are suggested. With the research capabilities brought by canine functional imaging, findings may improve our understanding of canine cognitive processes, identify neural correlates of behavioral traits, and provide early-life selection measures for dogs in working roles.