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Visual Impairment :
Special Educational Needs
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The temporal lobe of the brain, receiving information via the ventral stream, uses memory to interpret images, and we fill in missing detail or interpret ambiguous, illogical or impossible images using information we already have to make sense of what we are seeing. Optical illusions are a good way of illustrating this.
Optical illusion triangles

How many triangles can you see in this image ?

How many are there actually ?

This is an ambiguous image which can be interpreted in different ways.

What animal can you see here ?

Optical illusion - rabbit ro bird
Bird in the bush illusion

What does the text in the triangle actually say ?

Most of us would ignore the repeated word when we read it so that it makes sense

The workman is confused.

He has laid the tiles in parallel lines, but they look as if they are sloping.

Parallel rows illusion
Stool leg illusion

The Dutch artist, Mauritz Escher, draw many outstanding pictures which featured illusions and tricks with perspective. The cartoon of the  lady at the bar on the left is an example of an impossible image. The problem with the image is reinterpreted by the brain to match information in our memory, ignoring the problem.

Can you see the error in the drawing ?

We can fill in missing detail to read the following words.

Text diagram

 It is thought that we recognise the shapes of common words so understand meaning without reading every letter in the word. Can you work out what this sentence is ? (the answer is at the bottom of the page)

Text with letter replaced by block shapes

The temporal lobe also uses short term/working memory. This is the memory that we use when working. As it implies, it is short term and most have had experienced this when we put something down and can’t remember where we put it. It is important in problem solving. The spot-the-difference cartoon below has 15 differences. To identify them we keep the two images in our working memory simultaneously.
(Click the image to load a large copy of the cartoons)

Spot the difference cartoon

The words read LIFT and TEXT. The sentence reads : the dog chased the cat up the tree (obvious, isn't it !)