Washington, Mar 5 : During a crowded and noisy cocktail party, cutting through the chatter for understanding a conversation is a gift given to humans, say researchers.
Scientists call this ability to listen to someone speaking while many others are talking loudly at the same time the cocktail-party-phenomenon and it stems from how the brain distinguishes the pitch of different voices.
It was thought for a long time that the direction where the sounds came from was the key to doing this.
Now, the latest study, led by Holger Schulze at the Leibniz-Institute for Neurobiology in Magdeburg, and the Universities of Ulm, Newcastle and Erlangen have found a neuronal mechanism in the auditory system that is able to solve the task based on the analysis of the temporal fine structure of the acoustic scene.
The findings show that different speakers have different temporal fine structure in their voiced speech and that such signals are represented in different areas of the auditory cortex according to this different time structure.
By means of a so-called winner-take-all algorithm, one of these representations gains control over all other representations.
This implies that only the voice of the speaker to whom you wish to listen is still represented in the auditory cortex and can thus be followed over time.
This predominance of the representation of one speaker's voice over the representations of all other speakers is achieved by long-range inhibitory interactions that are first described by Schulze and colleagues using functional neurophysiological, pharmacological and anatomical methods.
The results of the study provide a deeper understanding of how the parcellation of sensory input into perceptually distinct objects is realized in the brain, and may help to improve the auditory experience of hearing aid wearers at cocktail parties.
The study is published in PLoS ONE.