They got caught in social contagions and reinforced each other’s risk assessments.

他们都被这场蔓延的危机围困，重新加强互相的风险评估。

The essence of teaching is to make learning contagions and to have one idea spark another.

教学的精髓在于使学习具有感染力，使一个思想能激发另一个思想。