Cocktail party effect still raises strange questions.

The cocktail party effect is a phenomenon wherein the brain focuses a person's attention on a particular stimulus, usually auditory.

The cocktail party effect is a phenomenon wherein the brain focuses a person's attention on a particular stimulus, usually auditory. This focus excludes a range of other stimuli from conscious awareness, as when a partygoer follows a single conversation in a noisy room. This ability is widely distributed among humans, with most listeners more or less easily able to portion the totality of sound detected by the ears into distinct streams, and subsequently to decide which streams are most pertinent, excluding all or most others.