A function with a Low Excitation Threshold is stimulated by even the weakest signals, so they maintain focus and engagement in relatively “quiet” environments. These functions get bored and generally ignore high intensity stimuli, however. The output of these functions are, likewise, low intensity signals. These functions are highly sensitive and excel in areas requiring finesse and precision. They are, however, prone to false positives (partial hallucinations, unnecessary stimulation) and get easily overwhelmed in urgent and intense situation. An important thing to note is that the excitation caused by a stimulus decreases with repetition: the function builds a tolerance for that specific stimulus. As a result, these functions become more interested and engaged the more a stimulus is repeated: repetition brings the intensity down to their threshold.

A function with a High Excitation Threshold seeks excitement and strong stimulation but gets quickly bored in mundane or repetitive situations. These functions have poor attention to detail as well as direct, “brute force” approaches to problem solving, but they respond quickly and show great interest in unusual, exciting, or dangerous situations. They exhibit thrill-seeking behavior combined with a general indifference toward small inconveniences and obstacles. These functions get quickly bored in repetitive or monotonous situations, searching instead for a constant stream of novel input.

In the example below you can see the excitation thresholds for ENFJ and ISTJ.