It's all in your mind...

To start things off, thinking about how good our sense of sight is as a scientific data collection instrument, we explored how accurate our powers of observation are and some ways in which we can get false observations (did you realise that was what you were doing?)

First we tested how selective our observations were. In this video...

...no one got the number of white player passes exactly right but everyone was close (a range of recorded passes of between 12 and 16 with the exact result being 15 so an error of up to 20% on just counting to 15!) and half the group did not record the additional interesting observation! It just shows how difficult it can be to make detailed observations particularly where the data do not fit our hypotheses – our mind filters the information and applies an interpretation to what we see before it gets into our conscious mind - let alone being able to keep it accurately in our memory.

Here are some some quite alarming illustrations of how selective our observations can be!

So if our brain is applying some data processing to the data sent from our eyes – how easy is it to exploit that processing to trick our brain into seeing more than is really there?

We started making 3d selfies – the pictures are just flat, but we can arrange for our eyes to each see slightly different things by using colour filters. The left eye gets a view that emphasises a photo taken from one position that is made redder by having a red filter in our ‘3D glasses’. The right eye has a blue (cyan actually which is green and blue) filter which cuts down the red light and dims the first photo whilst allowing green and blue light from a bluey photo taken from four inches to the right. It preferentially sees the right hand photo. Thus each eye is presented with a view mostly made up of the same image that it would get if it was looking at a real three dimensional person. Of course there is a bit of the photo still getting through to the wrong eye, and the colours are all a bit wrong, but our brain knows what it expects and can tidy up the signal that it is getting down the optic nerve: we ‘see’ normal colours and our brain decides that it is looking at a three dimensional person – neat! It is just a flat pattern of colours, but by giving the brain something that it is used to seeing, the brain tidies up any minor inconsistencies and sees what it wants to! Very cool for making arty pictures but a bit worrying for being accurate when doing experiments if what we ‘see’ is what we expect and our brain tries to get rid of anything unusual or interesting (like a gorilla perhaps!).

Here’s one of our 3D anaglyph selfies!

and another...

left

right

3D

And a link to the program that overlays the two photos.

Oh, and a dragon :)

Next week we will try and find more ways to use what we know the brain will do to make interesting pictures (optical illusions!) and also make auto-stereograms – a different way to trick the brain into thinking it is looking at a 3D object (and also to hide a message!)

Here are our photos