The Sensitive Brain

Our senses are constantly bombarded with information from the world around us. To cope with the non-stop input, our brain focuses on the particular types of information that are most crucial to its functioning. It pays less attention to other information. While this characteristic of the brain helps us live our lives efficiently, it sometimes creates illusions.

Everything's relative
The characteristics of objects we perceive are not constant; they change in relation to the environment in which they are located. If you ask your brain if something is hot or cold, dark or light, large or small, etc., it will give you a relative answer – compared to what? Therefore, our perceptions of a single object can be very different, depending on the context.

Sudden changes
Our brain is specially designed to identify sudden changes in time or space. It alerts us immediately that danger is near. That is why dramatic changes in light or color grab our attention and we are less aware of gradual changes.

A Horse of a Different Color
We often see the same object under different light conditions (in sun or shade, for instance). The brain tries to retain the true color of the object, despite the changes in its environment. It "fixes" our perception by taking the light conditions into account, and at the same time it might be creating an illusion.

Our senses of sight, hearing, and touch are constantly demonstrating all of these phenomena. Some illusions have no definitive explanation. Can you supply your own explanation for them?