Ames Room Illusion

Today’s post is about a visual illusion which at first looks like there is some type of CGI or editing – but I promise it’s just how our brains interpret visual information! Have a look at this image below..

Ames room

In this ‘Ames Room illusion’ the girl appears to be much bigger when in the right hand corner of the room, compared to the girl on the left. However, if you were to take these girls out of the room and stand them next to each other, they would be exactly the same height. So what causes them to look so different?

The answer lies in the way the brain views objects in relation to their context. Even if we knew these girls were the same height, our brains would still interpret this image in the same way (therefore this illusion is ‘cognitively impenetrable’). At first glance, it looks like the girls are standing next to each other, although this isn’t strictly true. We assume that they are standing in a square room, because that’s generally the shape rooms are! However the image below shows it’s true shape, and explains why we view the figures in this way.2000px-Ames_room

The design of this room is so clever, because it is decorated to look square, but this illusion will only work if the scene is viewed from a specific point (see viewing peephole above). So the reason the girl on the left looks so small is simply because she’s further away. The two corners have the same visual angle from this viewing point, so they look as though there is a horizontal wall between them. Therefore, the image of this distorted room which is projected onto the retina is exactly the same as if the walls in the room are parallel. This is how we perceive the room, as our perception is influenced by prior knowledge of what rooms generally look like. This illusion is so strong that people seem to grow or shrink in size as they move from one corner to the other!

This illusion actually has some quite useful applications, mostly in film making instead of CGI when they need to create the effect of some characters being smaller. Notably – this was often used in Lord of the Rings to make the Hobbits seem smaller!


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