在本能理论zh:里面，钥匙刺激指的是一种刺激模式(即是一种特定的刺激或是几种特定的特征的组合)，当它被感知后就会得到本能运动的应答。通常这种刺激也被称作诱发者(德语:Auslöser),它来自于另一位社会成员并且会对社会行为产生影响;还有一些同义词信号刺激和知觉信号。行为学的代表人物将刺激过滤称之为 先天诱发机制(AAM)，刺激过滤的作用是将相关的的信息从不相关的信息里提取出来（即是对钥匙刺激的识别）并且触发种属特异的本能运动。

The term fixed action pattern (FAP), or modal action pattern, is sometimes used in ethology to denote an instinctive behavioral sequence that is relatively invariant within the species and almost inevitably runs to completion.

Fixed action patterns, or similar behaviour sequences, are produced by a neural network known as the innate releasing mechanism in response to an external sensory stimulus known as a sign stimulus or releaser. A fixed action pattern is one of the few types of behaviors which was thought to be "hard-wired" and instinctive.