During each 10-minute story, Helt intentionally yawned every 90 seconds.

在每组10分钟的故事中，Helt故意每隔90秒就打一次哈欠。

To find out when in life the behavior develops, Helt read a story to 120 healthy kids, ages one through six.

为了找到这种行为发生的确切年龄，Helt将120个1到6岁健康的孩子按年龄分组，每组二十个。

Specifically, Helt said, it could diffuse stress after a period of being on high alert and spread a feeling of calm through a group.

特别是它可以在经历一段高度紧张的阶段后，分散压力，在群体里传播平静的感觉。

"Emotional contagion seems to be a primal instinct that binds us together," said Molly Helt, a graduate student in clinical psychology at the University of Connecticut, Storrs.

“情绪感染似乎是我们每个人与生俱来的本能，”康涅狄格大学的临床心理学研究生Molly Helt说到。