The subconscious mind is sometimes refered to as "the hidden observer". Karl Pibram once stated that you can only attend to 7 plus minus 2 things consciously at the time. Your subconscious mind attends to everything else. When you are in a crowd talking to someone, and you suddenly hear someone say your name, you will immediately turn your attention to what they are saying. This is the work of the unconscious mind. It makes sure that you attend to what is important wether it happens inside or outside your body.

Dave Elman in his book "Hypnotherapy" explains how your unconscious mind is even aware of what is being said when you are sedated under an operation. He treated a woman who didn't feel well since she was operated. By regressing her to the time of the operation, she explained that the doctors said something like "She's never going to be the same". She didn't consciously know that she had heard this, and her subconscious mind interpreted it as if she was going to be ill the rest of her life. Elman suggested that it meant she would be more well than ever, and that this was the reason for the doctors notice during the operation. After that reeducation of the unconscious mind she began feeling well again.

Scientific studies show that if you show someone an amount of chinese symbols, that they don't understand the meaning of, they will be unable to reproduce them consciously, but able to recognize which ones they have seen before. You have probably tried this yourself, when you forget someones name, but you know you can pick it out from a list. The hidden observer records everything, and by the use of hypnosis, it can be recalled.