Why we fear of the dark?

     Our brains have been programmed in a way that whenever there is a lack of complete image a brain tries to fulfil or to complete it to understand.

Considered an example of an image which is getting generated on computer ,the image needs to be 100% complete rate to be able to display it so if the image is only 20% generated, then the remaining 80% area will be left blank. The computer won't be able to process it so what it will prompt that there is an error in this image.

Similar things happen with brain. Brain is programmed to understand hundred percent of the environment and when the environment generated in the brain is not hundred percent, it tries to fill that void with relatable objects and experiences we had.

Let's say you are in the dark and brain is able to only see 20% of the environment. Now on the basis of the 20% data, brain will try to understand the environment but only 20% data is not sufficient to process and understand it. Brain will take the files or the data from the folder which are similar to the environment like danger, ghosts or fear and put those elements in that 80% data so that it completes an image to understand it.

The absence of light is what makes the brain to complete the image with relevant objects in order to protect ourselves from the unknown environment. Brain tries to complete the image with the relative objects of the feelings like when we watch horror movies we are often shown the dark and violent characters or supernatural forces. We always relate the dark with the Supernatural activities so brain cautiously makes us understand that there is a danger out there so you should not take a risk and is a mechanism of preventing you from the disasters.