An automatic response is a type of REFLEX action that is triggered by an external stimulus. It is an immediate and involuntary response to a given situation or event. Automatic responses are often used in robotics and artificial intelligence, where they are programmed to respond to certain stimuli in a predetermined manner. They can also be found in the natural world, such as the knee-jerk REFLEX, which is an example of an automatic response to a sudden tap on the knee.