Try to guess the signal you are listening to in each ear
Presenting certain tone sequences to both ears produces some interesting audit illusions, including the one in this demonstration, described by Deutsch (1975).
Tones of 400 and 800 Hz alternate in both ears in opposite phase that is, when left ear receives 400 Hz, the right ear receives 800 Hz. About 99% of listeners hear a single low-frequency tone in one ear and a high-frequency tone in the other ear. Quite remarkably, when the headphones are reversed, most listeners hear the high tone; the low tone in the same ears as before (Deutsch, 1974).
Right-handed subjects usually hear the high tone in their right ear and the low tone in their left ear, regardless of how the headphones are oriented. Left-handed subje on the other hand, are just as likely to hear the high tone in the right ear as in the left. This is because in right-handed people, the left hemisphere is dominant (and its primary auditory input is from the right ear), whereas in left-handed people, either hemisphere may be dominant. High tones apparently are perceived as being heard at the ear that feeds the dominant hemisphere (Deutsch, 1975).