Deutsch's scale illusion

Discovered by Diana Deutsch in 1973, Deutsch's scale illusion is an auditory illusion produced by simultaneous ascending and descending major scales beginning in separate stereo channels with each successive note being switched to the opposite channel. With the left channel: C'-D-A-F--A-D-C'; and the right: C-B-E-G-E-B-C; the ear hears both: C'-B-A-G--A-B-C'; and: C-D-E-F--E-D-C. Two complex patterns are turned into two much simpler patterns. Using headphones, right handers tend to hear the higher melody on the right and the lower melody on the left; however, left handers, as a group, do not show this tendency.