Thursday, November 5, 2009

BRAIN RESPONDS TO HUMAN VOICE IN ONE FIFTH OF A SECOND



BBSRC-funded researchers have found that the sound of human voice can be recognised by the brain in less than one fifth of a second. The research could help scientists better understand conditions such as autism.

The study, conducted at the Centre for Cognitive Neuroimaging at the University of Glasgow, found that the brain recognises voices within a similar time-frame as it recognises faces – after around 170ms following presentation.

Ian Charest, a PhD student who conducted the study under the supervision of Professor Pascal Belin, said: “Because human social interactions rely heavily on facial and vocal expressions, the brain is likely to have developed the ability to process them very rapidly and efficiently. Since faces and voices are usually paired together in social communication, it makes sense that the brain would process them in a similar time-frame.”

Researchers tested 32 volunteers in an experiment in which electrical signals generated by the brain were measured using EEG caps as the volunteers listened to series of sounds comprising bird songs, environmental sounds and human voices.

They observed electric potentials related to voice that had twice the amplitude as those related to bird songs and environmental sounds in less than 200 milliseconds.

Ian, from Trois-Rivières, Québec, Canada added: “This knowledge may also help us understand conditions such as autism and help develop more accessible diagnostic tools. Autistic individuals have difficulties in social interactions and we observe abnormal brain activity after presentation of faces or voices in their brains.”

(Photo: BBSRC)

BBSRC

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