How Your Brain Analyzes Music

Everyone has a favorite best hits song — with a melody they love and lyrics that really move them. Have you ever stopped to think how the human brain can differentiate between the tune itself and the words associated with it? It’s puzzled philosophers and scientists for centuries. Now there may be an answer of sorts. A research team at McGill University announced this week that when the human brain hears a song, the sounds are automatically sent to two different parts of the brain. One on the right, and one on the left.

Professor Robert Zatorre, who teaches neurology at McGill’s Montreal campus, says that the left side of the human brain is able to decode speech patterns but can’t decipher melodies like those from trending playlists, while the right side of the human brain deciphers the melody but is unable to make sense of any verbal content. This goes a long way in explaining something that doctors have puzzled over for years when dealing with stroke patients. An independent research study in Germany found that patients who suffered a stroke on the left hemisphere of their brain were most likely to lose their ability to follow a tune. Furthermore, strokes on the left side of the human brain often leave patients with impaired speaking abilities and usually ends their enjoyment of songs and their ability to sing coherent lyrics of any sort.  

The idea for the research project, according to Zatorre, came from local songbirds. He said the research team at the University began wondering how songbirds were able to sing the same notes over and over again, without any variation, and then suddenly add new variations on their tunes. Instinct could account for the same tune over and over again, but how to account for variations? The two most important functions in creating and controlling music of any kind whether at concerts in the USA or from songbirds in the woods, says Zatorre, is length and fluctuation. Birds apparently have two separate areas of the brain that handle these tasks separately. So the question the team wanted to answer was: Does the human brain work the same way?

The research team had test subjects listen to different snippets of both popular and classical songs, and then observed the subjects as they tried to recreate the songs themselves. Brain scans revealed that when the lyrics were remembered, it was the right side of the brain that showed the most activity. Conversely, when subjects were asked to recreate the melody, it was the left side of the brain where the most synapses were firing.