The 'mysterious melody' was first described and published by Deutsch in 1972. This musical brain teaser shows how our of a piece of music can strongly influence how we hear it. Example 1 (on Track 20) consists of a well-known tune. All the names (C, D, E and so on) are correct, but the tones are distributed haphazardly among three different octaves. Listen to the tune and try to guess its name. The task is surprisingly difficult!
Example 2 (on Track 21) is identical to Example 1, except that now the tones are all in the same octave. You should have no difficulty in recognizing this tune. Once you know what to listen for, try Example 1 again - you might find it much easier to follow. If it is not obvious right away, listen a few more times and the tune should finally emerge.
Deutsch, D. Octave generalization and tune recognition. Perception and Psychophysics,1972, 11, 411-412. [PDF Document]
Deutsch, D. Octave equivalence and the processing of melodic sequences. Journal of the Acoustical Society of America, 1976, 60 , s94.
Deutsch, D. Octave generalization and melody identification. Perception and Psychophysics, 1978, 23, 91-92.
Deutsch, D. Octave generalization and the consolidation of melodic information. Canadian Journal of Psychology, 1979, 33, 201-205.
Deutsch, D. and Boulanger, R. C. Octave equivalence and the processing of tonal sequences. Music Perception, 1984, 2, 40-51.
Deutsch, D. Processing of pitch combinations. In D. Deutsch (Ed.) The psychology of music, 2nd Edition, Academic Press, 1999, 349-412. [PDF Document]