Auditory thresholds were determined in each subject on two different occasions, by a modified method of limits under 10 intensities of light. Coefficients of reliability and analyses of variance of the data showed significant reliability of responses to tones in introverts (I) and extraverts (E), under increasing intensities of light. The auditory responses were most reliable in I and least in ambiverts (A). The same visual stimuli produced the same effects on auditory sensitivity, in the same subjects, on different days. These effects included facilitation and inhibition of sensitivity in I, facilitation in E and A, and interaction of intensity conditions and personality type.