Specifically, we perceive color three-dimensionally, how many dimensions does our perception of sound have?
Edit:
I’m apparently having trouble expressing the question. I’m not asking about the physical mechanism, but the number of capacities of sensation. Many people have trichromacy, some have tetrachromacy. Is there something like that for hearing?
In: Biology
Sound is perceived by hair cells in the cochlea. Each hair cell is sensitive to a specific frequency. There are thousands of hair cells. So yes, there are similarities, but sound is perceived by a much more high-dimensional system.
Also our perception of sound has far higher time resolution and much lower spatial resolution than our perception of light.
It’s hard to explain how we hear sound in an ELI5 comment. But I’ll give it a shot. In your ear, you have the cochlea which is like a spiral structure. In the middle of that structure, you have a dividing compartment (to visualize this imagine a three lane street, and take that street then wrap it up in a spiral, the middle lane is this dividing compartment). On one side you have a membrane. From the beginning of the spiral to the end, this membrane’s width, stiffness, mass and damping properties gradually change. On the beginning of the spiral, you have a little window, on the window there is a tiny bone that is hinged on two others that are then connected to the eardrum. As the eardrum vibrates due to sound waves, these bones move and they amplify this vibration and transmit to the window. Inside the cochlea you have a fluid, and so essentially sound vibrations get converted to little waves in that fluid. The wave then travels in the fluid from this first window all the way to the center of the spiral after which it makes a U turn and continues back on the other side of that dividing compartment going back to another window in the beginning of the spiral. As the membrane has different properties along the spiral, it takes different frequencies of waves to make it oscillate. And so a sound of a given frequency will cause oscillation in a specific region of the membrane. Under the membrane you have hair cells which are cells with tiny projections, if the membrane oscillates say up and down, these projections bend as the hair cells are under it. Once they bend, tiny molecule channels in the projections open allowing ions through and inducing a change in the voltage across the hair cell membrane. This leads to the transmission of a signal to a neuron attached to that region of the spiral that goes to the brain. The brain knows which neuron corresponds to which region in the cochlea, so when one is activated, it can know which frequency of sound that is. So it’s not like sight at all, because a continuous spectrum of signal can activate the sense of heating.
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