How Do You Hear Your Favorite Song

Speech and music are two of the most cognitively complex skills we humans have. We're still trying to understand how our brain perceives them. We've known that the brain's two hemispheres process speech and music differently but exactly how has been a mystery. Now a new study has revealed that a song's melodies and lyrics are processed on opposite sides of the brain.

Researchers in this study began by asking whether human brains worked the same as birds. Birds process sounds by measuring its pitch and how it fluctuates. In a study, researchers combined ten sentences with ten melodies to create one hundred songs. They manipulated the recordings by changing the frequency and sometimes the time or beat. While people listened, their brains were measured with a functional MRI.

When the timing of the song was distorted, listeners' left brains were impacted and they could not understand the words. When the frequency of the song was distorted, the right brain showed activity and the subjects could not discern the melody. So, just like birds, humans use two different brain circuits, one on each side of the brain to process songs. And yet, we do not perceive songs as separate lyrics and melody but as one thing. The processing of a sound in those two brain regions is different than speech or music by themselves.

A next step is for scientists to figure out how the brain assembles the information. For now, you can marvel at the wonders of your brain whenever you sing your favorite tune.