And, in fact, once you teach an animal something, if you stop doing the teaching the response goes away and this is known as extinction.

事实上，条件反射形成以后，如果得不到强化,条件反应就会逐渐消失,这就是消退。

耶鲁公开课 - 心理学导论课程节选

wouldn't there be extinction after a while?

在强化消失后是否也会发生消退？

耶鲁公开课 - 心理学导论课程节选

These conditions permitted a development of institutions and habits needed for freedom, even as they also made Europe vulnerable to conquests and to extinction, and Europe was almost extinguished practically before there was a Europe; very early in its history.

这些恰恰是自由的形成和发展,需要的的制度和特征,尽管这也使欧洲,在外敌入侵时变的不堪一击,实际上,在它早期的历史中,欧洲在尚未形成前就差点消失

耶鲁公开课 - 古希腊历史简介课程节选