Visual Sensory "blank-outs"? Is it true that if you attempt to visually perceive something that is so strange and beyond your personal understanding, you will not be able to "see" it? In other words: If your brain doesn't already have that particular image stored somewhere and you try to view something that fits the image, will you simply not be able to visually sense it? I ask because I have read claims that the natives were unable to see the ships that Christopher Columbus and his crew sailed in on....they could see the water being displaced by something, but they didn't know why until one of the smarter natives explained the presence to the others. Would this make us a more vulnerable species than those with enhanced perception....like dolphins?