Tunnel-vision

Tunnel-vision is a proces where clues seem to lead us in a certain direction, whereafter following information seems to justify our presumption.
The first time I heard about it, was concerning an investigation by the police, where the investigating officers jumped to a conclusion in the first stages of an ongoing investigation. Thereupon all clues that conflicted with their conclusion were ignored (to be "of no importance" of "inconclusive") while clues that reinforced their idea were accentuated.
And yes, an innocent men was sent to prison for over 10 years....
Recently I came across the same problem with two students working on their final project. In an early stage they had a good brainwave, got a good idea (and the idea still is), but in the following research they just looked at facts that supported their initial design, while ignoring conflicting facts. And that is just no the right way a research should be executed. (And right so, because in their subsequent research they did find reasons to alter their original design, so came up with a better product in the end!)
And now we, apparently we fall for the same trap. Consider the following pictures:



Do you see any parallel lines? In the upper picture it is evident, but what about the lower? No? Neither do I. Nevertheless the horizontal line are parallel, although you can't see so. (Don't believe me, check!)

This was first discovered during the redecoration of a pub in Bristol, the owner decided that he like black and white tile alternating on the outside of his pub. The tiles were to be set in stretching bond (each tile is placed with its center on top of the border between two tiles). When the decoration was finished, it didn't please the owner, of course, it was not what he intended. Nowadays the pub is famous all over the world because of its outside tiles.

For an explanation of the effect, read the article from Bristol.

Speaking of a tunnel


When you see the spirals, you realise that you can go deeper and deeper. Unfortunately you jumped to the conclusion that it are spirals that you see. I suggest you follow the cirkels with your finger to be absolutely sure. There really is no tunnel to go into. But at least now you know why it is called tunnel-vision!.