A team of hearing scientists from the NTT Communication Science Laboraties in Kanagawa, Japan have found clues to how humans isolate one sound in a noisy environment and filter out the others, known as the “cocktail party problem.” Science Now describes the study:
They recruited volunteers and asked them to sit alone in a small room and face a speaker. Then the team played a combination of two different tones. At first, just like people at a loud party, the volunteers heard the sound as one cacophonous noise. But within a few seconds, they were able to isolate one tone from the other.
A humanoid robot called “Telehead,” with built-in microphones to mimic how we hear, was used to help the team find out if anything could reset this cocktail party effect. As the volunteers listened, they were asked to turn their heads towards the tones that they heard, and Telehead moved in sync to try to discover the consequences of head motion. The scientists found that rapid head motion resets the cocktail party effect, forcing the brain to re-filter the different sounds. Their research was published in the Proceedings of the National Academy of Sciences.