Neuroticism and the pupillary response to a brief exposure to noise.

'Neurotic' and 'stable' groups (n = 8) were formed by means of the Finnish version of the Eysenck Personality Inventory. Subjects were exposed individually to 80-100 dBA broadband noise. No overt response was made. The dependent variable was the pupil dilation. The louder the noise, the larger the pupil was. At each level of noise intensity, the dilation was largest immediately after the change of intensity. In general, the pupil size decreased in the course of the experiment, indicating habituation. The 'neurotic' subjects displayed the largest relative dilation as a function of noise intensity. Results are discussed in terms of the arousing effects of auditory stimulus intensity.