Horizon Illusions - Is Seeing Believing?

Horizon explores the strange and wonderful world of illusions - and reveals the tricks they play on our senses and why they fool us. But all this trickery has a serious purpose. It's helping scientists to create a new understanding of how our senses work - not as individual senses, but connected together.

Examples-

1.Spinning diamond

It can appear to spin in both directions because the sequence of 2-dimensional images on your eye is identical for a 3-D diamond spinning either to the left or to the right. When we look at the spinning diamond, our brain doesn't actually know which way it is spinning. And because both directions of motion are possible, it bounces between the two options depending on where in the diamond we are looking.

2.Brightness Illusion - colours out of place

If you put the mask on the picture you will see that they are in fact the same brightness.

This happens because our brain does not create its perceptions of brightness from only the intensity of a single surface or light in a scene, but according to the relationships between all the surfaces and lights in the scene. In other words the brain always uses context to figure out what's in front of it.

3.Impossible Slopes - depth perception
We see the balls appear to roll up the slopes of the model towards the middle.
This is because all the information in the image is consistent with the supporting legs of the model standing at right angles to the floor. Because of this, the brain interprets the middle leg as being the tallest leg in the model. Which means the ramps must actually slope upwards. As a result, the rolling balls appear to roll up - now down, which they really are.
Because the image hitting the retina is only 2 dimensional, in order to see the world in 3D, our brain must create its 3D perception based on its past experience of the most likely 3D configuration given the 2D image. Sometimes this means even perceiving a world that goes against the laws of physics.
When you change your perspective you see the slopes actually point downwards into the middle.

  

                   

 

Reflection  on language

I first of all think that it is very difficult to define the word language. I, personally, think that it is a form of communication using symbols and your vocal chords. I think that there is a difference between language and communication. As language is a form of communication. For example a monkey peeing on a tree to mark its territory is communication, however it is not using language as someone talking to someone on the phone would be communicating but also using language. When it comes to the problem ‘can you know something without language?’ I think that you can, because you have your eyes and you can recognize it. Also how are babies supposed to learn anything without language? Another thing I found interesting was the concept that your amount of language depends on where you are from and what your climate. For example in England it rains a lot so you have many words for rain, such as drizzle or spitting, or raining cats and dogs, however, in for example Egypt, there is probably only one word for rain. So in many ways language is a way of knowing for to know you have to communicate.