The human brain is a sneaky little organ. It is constantly carrying out processes relevant for both perception and function without letting you know a thing.
In the 1930s Sigmund Freud popularized the notion of the conscious versus the unconscious mind. According to Freud the conscious mind consists of all the mental processes within our awareness. The unconscious mind on the other hand, houses all sorts of things that we have no conscious awareness of.
Freud’s work on the unconscious mind was primarily based on patient analysis and personal insights and, as such, had no true empirical foundation. Flashing forward to the technological and methodological advances of contemporary neuroscience however and much evidence has been produced revealing silent workings of unconscious processing.
Just one example of the unconscious mind at work is seen in cases of blindsight. Blindsight refers to the capacity of certain blind individuals to accurately guess the identity, movement and location of visual stimuli even though they cannot consciously see anything at all.