Your peripheral vision makes up part of your overall field
of vision, which is around 190 degrees. However, it’s far from perfect, and
sometimes it causes us to see things which don’t really exist. We’ve found a
cool way to prove this to you.
All you need to do is focus on the cross at the centre of
the picture below, without glancing away. You’ll notice how your peripheral
vision turns people’s ordinary faces into those of ’monsters.’
The faces begin to become distorted, right? And the longer
we look at the centre of the picture, the greater the distortion. Why does this
happen? We’ll explain everything step by step.
There’s an area of our retina which is called the yellow
spot. It contains the largest number of receptors in the eyeball, thanks to
which we can see a given area more clearly. Let’s call this area the main field
of vision. It covers around 10% of the entire range of our vision, and shows
what our eyes are directly focused on.
In this case, our main field of vision is empty; there’s
just a dark area with a white cross. The brain tries to take information from
other sources located outside of the main field — in this case, the alternating
pictures on the left and right. These sources aren’t very ’reliable’, and the
brain tries to combine them into one image. It’s also trying to process the
photos in a very short period of time, since the images change very quickly. As
a result, the ability to discern faces is lost, and the brain simply joins
together different features from various faces into a single whole. Because of
this, we end up seeing ’monsters’!
Via : Bright Side