Timeline: The Cocktail Party Effect And The Superior Temporal Gyrus

Apr 22, 2019

Our ability to hear patterns, recognize words and focus our auditory perception is thanks, in large part, to a very specific region of the brain, the superior temporal gyrus. It’s located just behind and above each ear. It’s the site of our auditory association cortex, in other words it’s the place that helps us understand language, speech and music.

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You’re at a party. It’s loud. There’s music playing and people laughing and talking. There are decorations to catch your eye and smells that tempt your nose. All of your senses are bombarded at the same time. In the middle of the crowd you see a friend that you haven’t seen in a while and you’ve been dying to talk to. They call you over and the two of you meet up to begin a conversation. In the middle of all that noise and chaos suddenly you are tuned into the familiar voice of your friend as you catch up together. Everything else fades away into the background. We rarely even consider this amazing ability that we have to focus our attention on one thing while filtering out everything else. Scientists call this the cocktail party effect. We do this best when we have the use of both ears. For some reason our ability to hear in stereo is a benefit. Individuals with hearing loss, or who have lost their hearing in one ear have difficulty filtering out background noise.

Have you ever played “name that tune?” You know, you guess how many notes it would take for you to recognize a familiar melody? A group of researchers in Japan tried a very sophisticated version of this game in a 2013 study. They scanned the brains of participants from two categories, musicians and non-musicians. What they discovered is that, not only did the musicians have a better success rate, but their brains actually behaved differently. In non-musicians only one-side of their superior temporal gyrus would light up on the scan as they thought about the tune they were trying to identify, while musicians had both sides of the brain light up equally. Much like the cocktail party effect, there seems to be a benefit to stereo audio processing.

When you listen to music, your superior temporal gyrus starts to connect with the nucleus accumbens, another region responsible for expectations and prediction making. The more these two regions of the brain connect while you listen, the more your pleasure centers are involved; meaning you enjoy the music. Not only do you enjoy it, but you focus on its pattern and structure, like the cocktail party effect. You memorize the beat, the timbre of the instrument, the turn of the melody, so that when you experience the music again, you get a similar response. The music is training your brain. Research scientist Valerie Salmpoor of the Montreal Neurological Institute observed, “Each brain has been shaped by the music you have heard in the past.”

Why do we like certain styles of music and not others? How does music effect our perception of the world? These are questions that we are just beginning to understand, let alone answer. What do you think? How has music shaped your life and your experience? Let us know and comment below.

For further reading and exploration, check out these links and articles...

Timeline is an exploration into the development of Western music.