That's probably a fair general characterization of what is going on, but the core part is that our perceptual systems respond primarily to change - if things in

That's probably a fair general characterization of what is going on, but the core part is that our perceptual systems respond primarily to change - if things in our field of vision are not changing, they produce less of a "signal" in our brains. It's not our perceptual system that is switching modes as much as it is the world changing between active and static. In the MIB case, most of the field of view is constantly changing, providing a lot of signal, but the yellow dots are low signal, and so our brains happily fill in the static dots with the in-motion background around it. Moving your eyes, blinking, or moving your head around all introduce enough visual change to re-set the full visual field, which is why the yellow dots reappear. Through top-down attentional control, you can have some influence over whether/which dots disappear - in effect, you are turning up the signal gain on particular receptors in the visual field around the target dots. You can also see why this affects people with monocular vision just as well - a lot of this perceptual processing happens at a very low level, well before binocular cues get integrated.