There's no doubt that our peer groups exert enormous influence on our behavior.

毫无疑问，同龄人群体对我们的行为产生了巨大的影响。

Peer groups might influence such behaviors as smoking and obesity.

同辈群体有可能影响到吸烟或肥胖之类的行为。

It's not clear why, but one idea is that kids are susceptible to peer influence, and forming peer groups around bullies helps the bad behavior spread.

目前尚不清楚其原因，但有一种观点认为，孩子容易受到同龄人的影响，在欺负者周围形成同龄人群体有助于不良行为的传播。

They looked at the effect of divorce among peer groups on an individual's own risk of divorce and found a clear process of what the scientists called social contagion.

他们关注同龄人个体离婚对自己离婚的影响，并发现了一个清晰的过程，科学家称之为“社会感染”。