COCKTAIL PARTY EFFECT
The ability in perception to select one desired sound from a background of AMBIENT NOISE heard at the same time. For instance, at a party, where many voices are speaking simultaneously, we may 'focus' our ears on one voice and ignore others which are equally strong. Spatial differences in the location of the sources greatly assists this ability.
The inability to select a signal from the ambient context is a symptom of HEARING LOSS, as well as aphasia, which is not uncommon, especially with children.
See: BINAURAL HEARING, MASKING, MINIMUM AUDIBLE ANGLE, MONOPHONIC. Compare: BLEND, PRECEDENCE EFFECT, SIGNAL-TO-NOISE RATIO.
Sound Example: Two voices heard from the same location (mono) and then from two locations (stereo).