Listen up - our hearing is perfect for a cocktail party
Ever managed to isolate what a particular person is saying while simultaneously ignoring what another nearby person is saying? Well now scientists have discovered how we can control our hearing in this way.
Our auditory system is great at focussing on one voice. Hand gestures optional
The human auditory system is very good at focusing listening attention on a single speaker when there are loud background conversations - this effect is called the cocktail-party-phenomenon.
At first it was thought that this ability utilised the directional information from the source of the sound but although the skill improves with two ears, it still works monoaurally. For example a telephone conversation that provides no directional information can still be isolated.
Scientists from the Leibniz-Institute for Neurobiology in Magdeburg and the Universities of Ulm, Newcastle and Erlangen have found the neuronal mechanism responsible for the cocktail-party phenomenon. It turns out that different speakers have different fine structure in their voices that varies with time and the auditory system uses this feature to pick out individual speakers.
Different voices are represented in different areas of the auditory cortex (the region of the brain responsible for processing sound information). The dominance of one voice over the others is controlled by long-range inhibitory interactions, which the group describes using neurophysiological, pharmacological and anatomical methods published in PLoS ONE.
They hope that applying their new found knowledge of how distinct sound sources are processed in the brain may help to improve the experience of hearing aid wearers at cocktail parties and beyond.
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