Monday, 23 March 2015

A solid object moving only in parts

Crows in a treeAs promised in the last post, I've been out studying escalators. To recap, I previously noticed that the black moving handrails of an escalator could sometimes appear motionless when it couldn't be. It was an unusual example of a striking misperception. But I only saw it on one escalator, so I went to look at others, to see if it was a once off. Happliy, it wasn't!

I have seen the phenomenon on several different escalators now. I have even seen one section of a single handrail appear motionless when another part was visibly moving. Significantly, I could not see the two sections in one single view but only by shifting my gaze. If one part of a solid object was apparently moving while another was not, it could well give rise to reports of paranormal phenomena.

Anyway, here is what I've discovered from my initial research. Perhaps not surprisingly, the effect is heavily dependent on lighting conditions. The motionless appearance occurs where the black moving handrail is either strongly reflecting light, appearing shiny white, or very weakly doing so, appearing wholly dark. Both of these conditions mean you cannot see slight marks on the handrail that allow you to easily detect it moving. The effect occurred in good lighting conditions. The best distance for seeing the effect appeared to be from around 2 to 5 metres away. I was unable to see the handrail change state, from motionless to moving, or vice versa. This is typical of misperception. You either get one interpretation or another, never both and you do not see them change. It seems that our brains only allow is to see things that 'make sense'.

I was intrigued by why my brain should ever think that seeing a motionless handrail was a 'best guess' at what it was seeing, given that most escalators I see are working normally. Then I recalled that we actually see the handrail as motionless, even though it is actually moving, when riding the escalator. So the motionless state would actually be a common view of handrails. This provides a plausible explanation of why this bizarre misperception appears to be easily seen on escalators but not on other objects. I am now trying to think of other objects where this might also be true to see if the effect occurs elsewhere. Suggestions welcome!

No comments:

Post a Comment