The researchers found that those who breathed through the nose rather than the mouth were less likely to yawn when watching a video of other people yawning. This was because vessels in thenasal cavitysent cool blood to the brain.

• 研究人员发现，在看别人打呵欠的视频时，用鼻子呼吸的人比用口腔呼吸的人打呵欠的几率要小。这是因为鼻腔里的血管将温度较低的血液送到了脑部。