How does ear system and sound work ?
From compression wave to brain wave
When molecule pulsing is on its way through the air, a sound will arive at your ear. The outer, visible part of the ear funnels a wide spread of the compressions into the small hole in the side of your head, amplifying the wave.
Further into your head, the compression hits your ear-drum. This membrane moves back and forth as the shifting air molecules push and pull it. The eardrum passes the movement through three tiny bones - the smallest in the body - onto a second membrane called the oval window which sets fluid in the cochlea in motion.
The cochlea is a spiral-shaped bone chamber, which is filled with a watery fluid. The movement in the fluid is picked up by tiny tufts which look like hairs, but which are actually extensions of cell membranes. These stimulate the 'hair cells' at their base and generate signals in the auditory nerve, Just like in sight, what had been an external physical phenomenon has became an electrical signal travelling through a nerve to the brain, where it will be processed to build up sound picture.
We tend to think of hearing as a more straightforward sense than sight. There are so many well-known optical illusions that it;s not difficult to accept that the brain constructs a visual chimera taht is its attempt at building an image from the various inputs it receives. Sound, though we ten to think as just, well ... sound. We assume that what we hear is what's out there. But again the incoming raw dara is subject to processing and manipulation by your brain.
In this video you can experience audible illusion yourself.
Experience the McGurk effect
McGurk effect is a perceptual phenomenon that demonstrates an interaction between hearing and vision in speech perception. We witness this occurance when sound we hear is visualized by for example - talking mouth. If visualizations do not cross with up-coming sound our brain generates the best interpretation of these two. But if sound we hear contradicts with things we see things get little dizzy. Or in other words, our brain selects sight as more reliable information and changes the sound we hear so that it could fit the visualization.
If you want to experience McGurk effect, do as following:
- Watch video on the right (all 4 seconds look at man's mouth)
- Watch it again but this time try to understand what is this man repeating (still looking at his mouth)
- Close your eyes, watch the video again concentrating on the sound.
- You should hear different syllables with your eyes closed.
Some times some people can't experience McGurk effect. It's usually because of two reasons:
- inborn disorder
- too much time spent watching dubbed movies. Your brain gets used to ignoring the visualization of sound and only accepts sound you really hear without interpreting it.
Sounds we hear impact us greatly
Like sight, sound is much more than a simple source of information; it can powerfully influence our emotions. If there is a moment in a film that brings you close to tears it is liable to be the sudden swell in the music that trigers the emotional response. Even the absence of music can be effective in this way. If a drama makes heavy use of soundtrack, a sudden period of silence can build tenstion and add a feeling of real involvement.
Another example of the effect sound has on our emotions is when we fing a noise irritating. An irritating sound can dominate our senses. The most famous irritating noise is the sound produced by draggins your fingernails over a blackboard or slate. Analysis showed thats it's not the high frequencies that make the sound so distinctive. It has been suggested that the sound of fingernails on a blackboard might be similar to a pre-human warning cry, or the call of some long-forgotten predator.