Dogs display context-dependent behavioral responses to subtle owner-derived multimodal stimuli.

INTRODUCTION: Dogs (Canis familiaris) can discriminate explicit human emotions using various sensory modalities. However, their sensitivity to subtle human-derived emotional cues accompanied by physiological changes, but lacking clear behavioral cues, remains poorly understood. This study investigated whether dogs could perceive owner-derived emotional cues when suppressing explicit expressions. METHODS: Owners were assigned to either stress or relaxation conditions designed to induce stress or relaxation, respectively. Following the experimental manipulation, facial video, voice, and olfactory samples were collected during a standardized reading task and simultaneously presented to the dogs. The behavioral responses and heart rate variability (HRV) of the dogs during stimulus presentation were recorded. RESULTS: Owners exhibited elevated physiological arousal during both the control and stress induction periods, whereas negative mood increased only during stress induction. In response to these owner-derived stimuli, dogs under the stress condition displayed greater stimulus-directed attention toward control-derived stimuli than toward stress-derived stimuli. No clear effects of condition or stimulus type on dog HRV were observed; however, SDNN-based physiological synchrony between owners and dogs tended to increase with stress-derived stimuli. DISCUSSION: Our results suggest that dogs respond to complex owner-derived stimuli in a context-dependent manner. These findings suggest that dogs may respond to subtle combinations of owner-derived cues that reflect physiological arousal, subjective emotional state, and task-related influences.