Opponent process theory holds that the brain processes color by contrasting black and white, red and green, and yellow and blue.
I propose that a good color scheme is one that gives the eye a refuge from each of these oppositions.
Yellow and blue provide a rest from red-green opposition. Purple and cyan provide a rest from yellow-blue opposition. A good color scheme, by my theory should combine yellow or blue with purple or cyan.
Red and green are not at all restful, and should be used in moderation to draw the eye. Red provides a transition between yellow and purple, and green provides a transition between yellow and cyan.
This suggests the four color schemes below. Take care to assess each in isolation from the others, cover the rest with your hand if you need to.
For full effect, add some white-black opposition to one of the colors.
I suppose it might also be possible to have a color scheme that uses direct opposition in moderation, and making sure that there is still variation in all three channels.