Oxytocin induces positive expectations about ambivalent stimuli (cognitive bias) in dogs

Abstract Expectancy bias towards positive outcomes is a potential key to subjective well-being, and has been widely investigated in different species. Here we test whether oxytocin, suggested to play a role in human optimism and emotional processing, influences how dogs judge ambivalent situations (in a cognitive bias paradigm). Subjects first learned in a location discrimination task that a bowl either contained food (at the ‘positive’ location) or was empty (at the ‘negative’ location). Then, after receiving oxytocin or placebo nasal spray, they were presented with the bowl located halfway between the positive and negative positions in communicative or non-communicative contexts (N = 4 × 16). A Positive Expectancy Score was calculated for each subject using the latency to approach this ambivalent location. Compared to placebo groups, subjects that received oxytocin pretreatment showed a positive expectation bias in both contexts, and this effect was more pronounced in the communicative context. Our study provides the first evidence for the impact of oxytocin on dogs' judgement bias and also shows that the social-communicative nature of the task situation modulates the effect of oxytocin

The Way Dogs (Canis familiaris) Look at Human Emotional Faces Is Modulated by Oxytocin. An Eye-Tracking Study

Dogs have been shown to excel in reading human social cues, including facial cues. In the present study we used eye-tracking technology to further study dogs’ face processing abilities. It was found that dogs discriminated between human facial regions in their spontaneous viewing pattern and looked most to the eye region independently of facial expression. Furthermore dogs played most attention to the first two images presented, afterwards their attention dramatically decreases; a finding that has methodological implications. Increasing evidence indicates that the oxytocin system is involved in dogs’ human-directed social competence, thus as a next step we investigated the effects of oxytocin on processing of human facial emotions. It was found that oxytocin decreases dogs’ looking to the human faces expressing angry emotional expression. More interestingly, however, after oxytocin pre-treatment dogs’ preferential gaze toward the eye region when processing happy human facial expressions disappears. These results provide the first evidence that oxytocin is involved in the regulation of human face processing in dogs. The present study is one of the few empirical investigations that explore eye gaze patterns in naïve and untrained pet dogs using a non-invasive eye-tracking technique and thus offers unique but largely untapped method for studying social cognition in dogs