The opening four bars of Beethoven's fifth symphony are performed in pure octaves, with no other notes to color our perception of what we hear:
The notes are G G G E♭, F F F D
Taken alone with no other context, they appear to be more suggestive of E♭ Major than C minor, but I don't remember ever having heard it in the major mode, and can hardly imagine doing so. The repeated G almost instantly becomes a third instead of a 5th as soon as the universally familiar Bum-Bum-Bum-Baaaaaa sounds.
But why is this so? Is this purely a matter of memory? We know Beethoven's 5th! We hear it all the time. Is it, then, that we hear it as C minor before there is actually enough information present to establish the tonic? Or is there more in the first four measures to suggest C minor than I am seeing?
Similarly, in the ineradicable West Side Story's Maria, there is a measure with a perfect fifth that resolves to a tritone. What's this, you ask? Ah, but you can hear it, even though this flies in the face of what we typically think of standard consonance and dissonance.
I cannot, for copyright reasons, link to the real score, but for our purposes, this should be sufficient. The downbeat of measure 25 is the moment in question. ("Ma-RI-A! Say it loud and there's music playing.")
The notes there are accurate enough to demonstrate what I am talking about, though the midi playback (ugh!) skimps on that downbeat in a manner that no live performer ever would, so the aural effect is poor. Listening to the movie performance will do you better. You can start from 0:50, though the funny moment occurs at 0:58.1
So, the downbeat, the half-step descent from said downbeat, the short duration of the note, and the natural emphasis of the word "ma-RI-a" all serve to help us hear the downbeat as the emphasized dissonance followed by the "consonant" tritone.
But it seems to me again that what's really going on here may be the interference of memory: at every other "ma-RI-a" in the song, including the famous opening one, the "RI" is a more straightforward dissonance, and the following "-a" is its resolution. In this moment, we have maintained the same metrical pattern, the same rhythm, and the same emphasis. Only the intervals themselves have been reversed.
So, is this, again, a matter of tonal memory overriding our more typical harmonic understanding? Or is there something more going on that I am not seeing?
(Note: There may well be a few people out there who know the song well, and will say that they don't hear the dissonance-consonance pattern that I am suggesting. That's fine and well, but I have spoken to enough other musicians about this by this point in my life that I know I'm not even remotely alone in what I perceive here. If you don't hear it as I do, I do wonder what you hear instead!)
1 - It would be quite interesting to hear from folks who have never heard the song before whatsoever. None of the past instances of "ma-RI-a" are in that tiny clip from 0:50 to 1:00, so if those people do not hear the dissonance-consonance pattern that I'm suggesting, that would be evidence that memory is, indeed, playing a role in this!