Have you ever wondered why you can be in class listening to a lecture about Social Control in the Antebellum South or The Atomic Structure of Hydrogen, and accidentally get lost in thought only to realize five minutes later that you heard nothing your professor just said? You were in the class room. The sound hit your ears. Why didn’t you really hear it?
Have you ever pondered your ability to isolate the specific sounds of each individual instrument in a favorite song? If they are all playing at once, can we hear one of them better just because we want to?
Have you ever noticed that when you’re in a crowded room, although there are dozens of other noises and people talking, you can single out the voice of the person you’re having a conversation with, and hear virtually nothing else that’s going on around you?
These are all examples of “The Cocktail Party Effect.” In April, Erik Cooper, Director of Planning, Research, and Student Success, presented a two part lecture on this phenomenon and the science behind it.
He explained how speech, hearing, and vision work together to let your brain know what a sound is, what direction it’s coming from, and what is causing it.
He gave a quick overview of the path that sounds take as they travel from your ear to your brain and deliver the correct message. About halfway through that journey, sounds come to the superior olivary nucleus. This is the point where your brain starts having control over which sounds advance farther and which are inhibited. The ones that advance are the ones you are giving your attention to. The attention you give to a specific sound determines what your brain does with it. This is essentially the Cocktail Party Effect.
The amazing thing about this is, at that point in the journey the brain has not yet distinguished the pitch, volume, rhythm, or complexity of the sound, which are the factors that reveal what exactly the sound is. The brain actually decides whether it wants to hear the sound before it decides what the sound is.
Cooper also touched on a few things closely related to hearing and processing sounds.
He talked about the area of the brain that produces speech, called Broca’s Area, and the area that processes speech, Wernicke’s Area, to name two.