The cocktail party effect describes the ability to focus one’s listening attention on a single talker among a mixture of conversations and background noises, ignoring other conversations. This effect reveals one of the surprising abilities of our auditory system, which enables us to talk in a noisy place.
The effect can occur both when we are paying attention to one of the sounds around us and when it is invoked by a stimulus which grabs our attention suddenly. For example, when we are talking with our friend in a crowded party, we still can listen and understand what our friend says even if the place is very noisy, and can simultaneously ignore what another nearby person is saying. Then if someone over the other side of the party room calls out our name suddenly, we also notice that sound and respond to it immediately.
It was first described and named by Colin Cherry in 1953. Much of the early work in this area can be traced to problems faced by air traffic controllers in the early 1950s. At that time, controllers received messages from pilots over loudspeakers in the control tower. Hearing the intermixed voices of many pilots over a single loudspeaker made the controller’s task very difficult.
Cherry conducted attention experiments in which subjects were asked to listen to two different messages from a single loudspeaker at the same time and try to separate them. His work reveals that our ability to separate sounds from background noise is based on the characteristics of the sounds, such as the gender of the speaker, the direction from which the sound is coming, the pitch, or the speaking speed.
This phenomenon is still very much a subject of research, in humans as well as in computer implementations, where it is typically referred to as source separation or blind source separation. The neural mechanism in human brains is not yet fully clear.