A shadow ghost

So, I know a door where a shadow ghost visits. It is only seen from indoors and only occasionally at unpredictable times. It is an outer door with a frosted window so anyone standing outside is visible but not necessarily recognisable from inside. The shadow ghost is different from a real person outside because it is only seen in peripheral vision and vanishes when you look straight at it. The ‘ghost’ always looks dark, never moves, and its shape is indistinct but large. The figure has been seen from various different positions in the room.

So what is it? I think it is a peripheral vision misperception. Why? Like many reports of shadow ghosts it is dark and seen in peripheral vision only. I think such ‘figures’ are dark because peripheral vision relies on rods in the retina that only see black and white as well as not seeing detail well (see here). Such figures vanish when seen straight on because misperceptions 'break' when the underlying object is seen well. In this particular case I think there is a particular pattern of light in the frosted window, that only occurs in certain specific conditions, that is being misperceived rather than a solid object. I have often seen misperceptions caused by shadows. Being a window to the outdoors, the light is constantly changing on it all day. Why misperceive the pattern of light as a figure? Misperception chooses likely objects to substitute for what’s actually there. A human figure is a highly likely object to be seen the in the door window!

Shadow ghosts are often reported in doorways seen in peripheral vision. Sometimes they appear to change shape. I have often seen this phenomenon with misperception as the brain tries various objects to fit what it actually sees.  I suspect peripheral vision  misperception is behind many reports of shadow ghosts. And the picture? Not a shadow ghost but some strange reflections.