Brighter noise: Sensory enhancement of perceived loudness by concurrent visual stimulation

Two experiments investigated the effect of concurrently presented light on the perceived loudness of a low-level burst of white noise. The results suggest two points. First, white noise presented with light tends to be rated as louder than noise presented alone. Second, the enhancement in loudness judgments is resistant to two experimental manipulations: varying the probability that light accompanies sound and shifting from a rating method to a forced choice comparison. Both manipulations were previously shown to eliminate a complementary noise-induced enhancement in ratings of brightness. Whereas noise-induced enhancement of brightness seems to reflect a late-stage decisional process, such as a response bias, the present results suggest that light-induced enhancement of loudness may reflect an early-stage sensory interaction.