Empathy enhances decoding accuracy of human neurophysiological responses to emotional facial expressions of humans and dogs.

Despite the growing interest in the non-human animal emotionality, we currently know little about the human brain processing of non-conspecific emotional expressions. Here, we characterized the millisecond-scale temporal dynamics of human brain responses to conspecific human and non-conspecific canine emotional facial expressions. Our results revealed generally similar cortical responses to human and dog facial expressions in the occipital cortex during the first 500 ms, temporal cortex at 100-500 ms and parietal cortex at 150-350 ms from the stimulus onset. Responses to dog faces were pronounced at the latencies in temporal cortices corresponding to the time windows of early posterior negativity (EPN) and late posterior positivity (LPP), suggesting attentional engagement to emotionally salient stimuli. We also utilized support vector machine -based classifiers to discriminate between the brain responses to different images. The subject trait-level empathy correlated with the accuracy of classifying the brain responses of aggressive from happy dog faces, and happy from neutral human faces. This result likely reflects the attentional enhancement provoked by the subjective ecological salience of the stimuli.