The 'cocktail party' effect explains a phenomenon that occurs when focusing on a single source of auditory stimuli among the multiple sources of noise. When focus is applied, everything outside the range of focus is effectively tuned out of the individual's perception. This does not mean that the brain stops processing the background stimuli. A word or phrase of importance to the individual will catch their attention and shift their focus. This effect highlights how information is filtered to our conscious or subconscious.