Decoded: How we recognise familiar sound

Ever wondered how you figured out the similarities between the song "Mamma Mia" by the Swedish pop group ABBA and "Mil Gaya Hum Ko Saathi" from the film "Hum Kisi Se Kam Nahin"?

The secret lies in the working of the brain's motor network, a study shows.

"The brain quickly compares incoming auditory information with motor information stored in memory, allowing us to recognise whether a sound is familiar," the study said.

The chances of remembering familiar music is more if you play it yourself.

"The memory benefit that comes from performing a melody rather than just listening to it, or saying a word out loud rather than just hearing or reading it, is known as the 'production effect' on memory," explained professor Caroline Palmer from McGill University in Canada.

For the study, researchers recruited 20 skilled pianists from Lyon, France.

The group was asked to learn simple melodies by either hearing them several times or performing them several times on a piano.

Pianists then heard all of the melodies they had learned - some of which contained wrong notes - while their brain electric signals were measured using the electroencephalography (EEG) test.

"We found that pianists were better at recognising pitch changes in melodies they had performed earlier," said Brian Mathias, a PhD student from McGill University.

The team found that EEG measurements revealed larger changes in brain waves and increased motor activity for previously performed melodies than for heard melodies about 200 milliseconds after the wrong notes.

The research appeared in the journal Cerebral Cortex.