system
Given the following post, respond as if you're commenting on Reddit:
human
Does the human brain (or the brain of any mammal, for that matter) perform Fourier Transform to decompose various sounds we/mammals hear everyday?

In many of my signal analysis and other engineering classes, we have to perform Fourier Transforms to analyze specific time domain problems in its frequency domain and decompose respective signals. These problems got me wondering whether our or a mammal’s brain decomposes various sounds that heard everyday. For instance, if we’re talking with a friend in a public space, how does our brain know which sounds to filter out (other people talking in the vicinity) and which sounds not to filter out (sound of a friend’s voice). Is this mechanism simply the brain performing Fourier Transforms instantaneously or is it simply a biological mechanism?
gpt
The translation from soundwaves in the air to signals in the brain happens in the cochlea. This is a little organ in your ear with the biophysical property that higher frequencies make the nearby end resonate while lower frequency waves vibrate the far end. Different locations along the cochlea have different little hairs that send electrical signals to the brain once they are mechanically activated. The brain therefore receives a (slightly noisy) Fourier transform of the sound.

Filtering out sounds is a very non-trivial task, of which it has not been totally figured out yet how the brain manages. This is known in the literature as the cocktail party problem. Partially the answer is based on the familiarity of certain sounds, partially it uses our stereo hearing and outer ear shape to filter out locations. Even with this information, building a machine that filters out everything but the person next to you at a cocktail party is extremely difficult.