Last week I discussed how if you have a limited vocal range but want to get some momentum in your song through instrumental/harmonic forces then oblique motion is a good tool. I used Bob Dylan's "Like a Rolling Stone" as an example of how a famous singer/songwriter could work around his legendarily small vocal range by which chords he played on rhythm guitar.
Well suppose you have a vocal range that seems almost limitless but you want a musical effect that is very dramatic and can be handled within a narrow range anyway? It just so happens that Stevie Wonder is the man for this task. In Superwoman/Where Were You When I Needed You this is exactly what he does. Sure, there's elements of oblique motion in here, too, but the key thing is the modal mutation. In the opening hooks for both halves of this song Wonder opens with a sweet, lyrical lilting tune in a very narrow range (a third for Superwoman and a rising and falling melody within a fifth in Where).
What he immediately does in the second half of the initial phrase is what we theory fans would call modal mutation. On a staff the note names would not change, they would still be in the same spots on the staff lines and spaces, but the nature of the naming would change. Where "Superwoman" starts with E major the melody shifts into E minor (parallel minor, which means the tonic/root chord hasn't changed but the scale we're building from it has). Because Wonder hasn't modulated but has drastically changed the key the theoretical name for this kind of device is mutation rather than modulation.
Modal mutation is the wonderful harmonic device that defines the hooks of both halves of this classic double-feature of pop music. It's used to great musical effect in both cases. In the first part we're told about how Mary wants to be a superwoman but it's not going to happen because of who she is. The bright optimism of the opening major-key phrase is instantly blunted by the tune being repeated in parallel minor. In the second half of the song the coming of summer is mentioned with a shimmering major (seventh) chord but now that summer's gone? The melody Wonder sings turns to parallel minor. The modal mutation is actually very violent but because of the sing-song rising up and down within the scale is what it is Wonder lets this harmonically violent gesture become gentle and wistful. He's trying to convey that this hurts a lot but he's trying to be nice about it, if you will.
The minor form of the key dominates in the second half where it was major in the first part of the song but the rising chromatically altered bass line is steady in both halves. "I think I can deal with everything going through your head" is the same rising pattern for 'where were you when I needed you last winter". The same music line serves as a harmonic mirror image text-painting two opposite sentiments from the same failed relationship. In the first half we're told about he thinks he can cope with everything in the woman's head but in the second half we see that she bails on him (for reasons that don't have to be especially clear) and the pattern could be laid out as follows:
Subtonic (major chord built a whole step below tonic)
Tonic (with a passing leading tone/dominant function in the second half to restabilize the entry for the major key phrase before the next modal mutation pattern).
Now I don't actually have the sheet music for this or access to what I would consider a reliable transcription or arrangement but because what I'm analyzing is chiefly the bass line and Wonder's voice with a broad reference to harmony these observations are "probably" okay.
If you want a dramatic musical shift and want to do it within a melodically narrow range this is a good compositional/harmonic device to use if the material you're working with (textually or thematically/melodically) warrants it. In classical music one of the masters of modal mutation within phrases as a source of pathos or comedy would be Haydn. It's not a big shock, is it, that in classical music and pop music masters of modal mutation might still tend toward the happy and upbeat but use modal mutation as a way to cultivate an element of surprise (Haydn did get one of his symphonies nicknamed the "Surprise" symphony, after all, but not necessarily for modal mutation).
So, uh, here endeth the lesson.