Knee-jerk
Adjective meaning readily predictable to the point of being automatic.
Knee-jerk often has a negative connotation and conveys the idea of an all-too-hasty, impulsive, irrational response based on a preset idea.
For example, a dictator's knee-jerk response to a democratic movement is to suppress it.
The term is derived from the reaction which has been so often tested as to become a familiar figure of speech.
For more about the knee-jerk reaction, see: Knee jerk .