Assessing Emotional Vocalizations From Cultural In-Group and Out-Group Depends on Oxytocin

Group-living animals, humans included, produce vocalizations like screams, growls, laughs, and victory calls. Accurately decoding such emotional vocalizations serves both individual and group functioning, suggesting that (i) vocalizations from in-group members may be privileged, in terms of speed and accuracy of processing, and (ii) such processing may depend on evolutionary ancient neural circuitries that sustain and enable cooperation with and protection of the in-group against outside threat. Here, we examined this possibility and focused on the neuropeptide oxytocin. Dutch participants self-administered oxytocin or placebo (double-blind, placebo-controlled study design) and responded to emotional vocalizations produced by cultural in-group members (Native Dutch) and cultural out-group members (Namibian Himba). In-group vocalizations were recognized faster and more accurately than out-group vocalizations, and oxytocin enhanced accurate decoding of specific vocalizations from one's cultural out-grouptriumph and anger. We discuss possible explanations and suggest avenues for new research.