What Do You See?

This brief piece in Psychology Today includes a true story about a workman who jumps from considerable height on to a nail, which goes through his boot from below and emerges from the top. He is understandably in agony until the boot is removed and he finds that the nail has gone between his toes without breaking the skin. The author concludes that "what you see is defined in large part by what you look for and expect to see". I'm not sure it's a perfect example, but it's memorable

The same point is researched and stated more formally in a piece in Nature, based on vision experiments in a lab. They conclude that "when we approach a new visual scene, the brain does not build it from scratch but compares the new stimulus with the trace of past information and obtains an ‘intermediate’ representation". They even suggest that unusual perception, like autism and hallucinations, may be linked to this phenomenon

When MrsM turned in a doorway, looked up and saw this, she said, "Oh, the Tardis"; I agreed immediately. Is that what you saw? Or do you see a cupboard - probably a wardrobe - suspended in the air, with some decoration that looks like pictograms and may or may not be authentic? The shadows and leaf silhouettes on the arched roof might look to a suggestible mind a bit like time dilation, but you probably didn't think that either. The fact is, it looks nothing like a Tardis

The missing factor is the past information - what we had just seen. It's in the extra