Pseudoscope

Next up on the Calvacade of Learning Experiences!  (I thought “Calvacade of Failure” had a nice ring to it, but… optimism, please.)

A pseudoscope is a device that flips the line of sight of your eyes; that is, the line of sight of your right eye is transposed with that of your left eye, and vice versa.  The purpose of pseudoscopes was to help figure out how people process depth information.  Supposedly, the actual visual input being reconciled with the expected input results in some convex shapes being seen as concave, flipped depth values for objects in close proximity, and other oddities.

Unfortunately, it didn’t work for me.

Rather than purchase a $750 pseudoscope, I followed the instructions here, which result in a rather more economical $10 pseudoscope.

Pseudoscope Parts

Pseudoscope Parts

The above picture shows the parts I started with.  Nitpickily observant readers will note that the mirrors are too small for the instructions given at the link.  This is because these were the closest size available at the store.  As I discovered, optical devices require a bit more precision than “whatever they had at the store”, and so I later purchased the correctly sized mirrors online.  Financially observant readers will now note that this device cost rather more than the expected $10.

A bit of measuring and assembly later:

Pseudoscope

Pseudoscope

In the picture above, your eyes should be placed at middle left, and the field of view extends to the right.  The logic behind the mirror placement is evident.

As I said, this doesn’t work for me.  I spent an hour or so focussing it, rather like a coincidence rangefinder, moving the two images together, and then looking at different objects under different conditions.  Inside, outside, dark, or light, with a long or short focal distance, my brain resolutely refused to be tricked.  The only oddity I noticed was the path distance added by the pseudoscope made me misjudge how close nearby objects were.

I can think of a few reasons why this didn’t work for me.  I am reasonably sure I got the focus right, so this probably is not it.  The first possibility is that I needed still larger mirrors to completely cover my field of view, and that there was enough reference information left unreflected by the mirrors that my brain was not misled.  The other possibility is that it did not work for me because I am about 70% left eye dominant, which both mucks up the positioning of the mirrors and puts another reference point into the equation that my brain was processing.  This too may have been enough information to prevent the illusion for taking effect.

In any event, I’ve spent enough time on it, and so it will go on the shelf of interesting ideas that didn’t pan out.

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