Abstract
A concurrent auditory stimulus can improve luminance change detection. This could partly be due to a cross-modal interaction where an increase in sound intensity causes an increase in perceived brightness (Stein et al., J. Cog. Neurosci., 1996, 8:6, pp. 497–506). In that case, we would also expect that a decrease in sound intensity would decrease perceived brightness and impede detection of a luminance increase. Thus, generally, we would expect that a congruent sound intensity change would improve luminance change detection while an incongruent sound intensity change would impede it. To test this hypothesis, we designed a luminance change detection paradigm. Participants (N=8) were asked to detect which of two rectangles changed in luminance from a baseline of 63 cd/m2. The luminance change magnitude was 1 cd/m2, the duration was 100 ms and the onset varied randomly between 1–3 s after trial onset. Auditory white noise was presented concurrently with the two rectangles. Sound intensity increased from 65 dB(A) to 80 dB(A), decreased from 80 dB(A) to 65 dB(A) or remained constant at 80 dB(A) during the luminance change. We found that a change in sound intensity significantly increased the probability of correctly detecting in which of the two rectangles the luminance change occurred. However, this effect did not depend on the congruence of sound intensity and luminance change. This indicates that auditory enhancement of luminance change detectability is not due to an interaction between sound intensity and perceived brightness for the stimulus configuration employed in our study.