Your eyes see the world as a flat, two dimensional 2D picture, such as a photograph or drawing. But your brain changes this flat picture into a three dimensiona 3D world, with depth, movement and perspective per SPEK tiv. Perspective is how your eyes see objects differently depending on how far away from you they are.
Because your brain is so good at converting 2D images into 3D images, when we see 2D images that only look 3D, it is easy to trick the brain into seeing strange things. For example, look at this picture of a staircase.
It was designed by a scientist named Penrose. Follow the staircase around with your eyes. It never ends! The stairs go both up and down without ever getting any lower or higher
The area of the brain called the temporal lobe is partly responsible for our ability to recognise faces. Some of the neurons in the temporal lobe respond to particular facial features.
When the appearance of a face is changed (or, in this case, turned upside down), neurons in the temporal lobe generate less activity. Look at the photos above.
Does the person look different? Scientists do not completely understand how people recognise faces. They do know that people find it more difficult to recognise faces when they are upside-down
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