One interesting notion is that of stimulus generalization. 刺激泛化是个很有意思的概念。
Stimulus Generalization in Two Associative Learning Processes 两个联想学习过程中的刺激类化
In real life we are unlikely to be fear conditioned for a meaningless stimulus, the one which contained threat information is easier to be paried with fear. And maybe generalization is based along dimensions of fear relevance. 在现实生活中,我们不大可能会对一个没有意义的刺激习得恐惧,我们更容易对一个本身带有威胁信息的刺激习得恐惧。