Long-term high altitude exposure reduces positive bias of facial recognition: Evidence from event-related potential

High-altitude environments influence emotional biases. Nonetheless, the neural mechanisms underlying emotional facial processing, which could help explain depression due to high altitudes, remain unexplored. An emotional face recognition task was used to explore the impact of high-altitude hypoxia on emotional face recognition and event-related potentials were recorded in relation to a high-altitude group (n = 22) and a low-altitude group (n = 24). The results showed that the high-altitude group had longer reaction time, lower accuracy rates, and more negative P1 and N170 amplitudes. Moreover, compared with the low-altitude group, the positive bias of the N170 component in the high-altitude group decreased, and the right hemispheric lateralization of the P1 component disappeared. These results suggest that early and late stages of facial processing are influenced by high-altitude hypoxia. The decrease in positive bias in late processing may explain depression due to high altitudes.