February 22nd, 2015
When at a noisy party or simply in a crowded bar, it’s sometimes hard to focus on a single voice and pay attention to what the person is saying, but still we manage somehow to hear it among all the noise. This phenomenon is known as the “cocktail party effect”. Now two researchers at the University of California, San Francisco, have identified for the first time how it works in the brain.
The researchers, Nima Mesgarani and Edward F. Chang, measured the reaction of the auditory cortex to two voices coming from the same speaker. Through electrodes implanted in the brains of the subjects, they were able to see that the brain processed the sound as if only there was one voice.
‘These findings demonstrate that the cortical representation of speech does not merely reflect the external acoustic environment, but instead gives rise to the perceptual aspects relevant for the listener’s intended goal,’ they write in the paper.
This finding, published in Nature, may help develop reliable voice recognition systems, which at the moment present problems when there are too many voices at once.
Smith, K. (2012). Brain discards voices to cope with cocktail party Nature DOI: 10.1038/nature.2012.10466