Two interesting similarities between visual and auditory modalities
In his great blog, Chris Chatham mentions two interesting phenomena that seem to be evidence for similarities in the way that vision and audition are processed:
“Lateral suppression can be observed both within the auditory and the visual systems as well. In the case of vision, this takes the form of mach bands, in which adjacent bars of increasing luminance show contrast effects at their edges. In the case of audition, the masking threshold is much lower for those sounds that coincide with the cutoff frequencies of a non-simultaneous noise mask; in other words, it becomes easier to hear the masked tone when it exists near the edges of the mask because of increased perception of contrast. In both cases, there are contrast effects that appear at the “edges” (whether auditory or visual) of stimuli.
There are also similar figure vs. ground phenomena in both visual and auditory stimuli. In vision, Rubin’s illusion shows how a bistable stimulus can appear to have one of two possible figures (face or vase) superimposed on one of two possible backgrounds (white or black). In audition, a similar effect occurs in pulsation threshold masking, when one auditory stimulus appears to be superimposed over another. Even though neither is truly a “background” sound, since both are pulsating, one is perceived as occurring continuously “behind” the other. Both these scenarios exhibit pattern completion or, to use the gestalt phrase, good continuation.”