Notice how in the bottom-left background color the foreground's perceived value is less than the value of the top left foreground hue. That is because the bottom left's background hue is lighter in value and its after-image will tone down the foreground hue. When juxtaposed colors are close to each other's value, the shift is less, because each after-image is also in the same value range, so there is a sort of wash of color. Not only can a hue be shifted in value, intensity and hue, it can be shifted in size. In the next experiment the same red foreground hue has been placed on background hues of varying intensities.
Darker colors tend to be expansive while lighter colors tend to be constrictive.
The expansive or constrictive quality of a color is relative to its saturation, i.e. the amount of hue. A heavily saturated color, when in dominance, will be expansive to even fully saturated non-dominate colors. In the example below, not only is the perceived values of lightness and hue being shifted, so is the perceived size of the red square.