The apparent decline in the ear's response under sustained stimulation, phenomenon which has been variously labeled “auditory fatigue,” “perstimulatory fatigue,” and “auditory adaptation,” was measured for pure tones over a wide range of frequencies and intensities by the median‐plane‐localization method.
For a given intensity, increasing the frequency from 125 to 1000 cps increased both the initial rate and maximum amount of adaptation. Above 1000 cps further increases frequency did not appreciably change the adaptation curves.
For a given frequency, increasing the intensity of the sustained stimulus also increased both initial rate and maximum amount of adaptation. The function relating adaptation, in db; to stimulus intensity was, in general, negatively accelerated.
The duration of sustained stimulation at which adaptation reached maximum value was related to both frequency and intensity.