That's not the only reason why children hear more and louder. When you're in your '30s you already have a minor hearing loss, you don't hear all sounds and noises then you did when you were 5. Children see more colours as well.
The cone cell of the human eye is the main type of photoreceptor that senses differences in light bandwidth, aka color. The dics of the cone cell are tuned to be receptive to certain bandwidths of light. These bandwidths are well understood and do not change as humans age (outside of damage to them)[0]. Humans only have 3 sets of these cones and do not gain or loose new types of cones as we age. The receptive bandwidths of the pigments are set by the biophysics of the molecules.
The perception of color does change as humans age, however. Typically, a newborn cannot yet use their eyes well. They can percieve light and dark, then red, then they can process depth, etc. This learning process takes a few weeks to months[1].
The cognition of color is a very in depth and facinating field. Thus far, it appears that color is a cultural and learned thing, in that if your language does not have a word for a color, it seems to be very difficult to determine the color as a different one from among other colors. Translating the mix of photons that your photreceptors are affected by into usable language is a very complicated process and is not well understood yet.
Fun Fact: The Illiad does not include the word blue and the Bible uses it very rarely as well.
[0] https://en.wikipedia.org/wiki/Cone_cell
[1] http://www.bausch.com/vision-and-age/infant-eyes/eye-develop...
In short they specifically go into how we perceive color etc. great show!
I'm guessing that hair dryers have a scream in the upper register that adults don't normally hear.
> The Mosquito or Mosquito alarm is a hand wound machine used to deter loitering by young people by emitting sound at high frequency, in some versions so it can be heard mostly by younger people.
> The sound was made into a mobile phone ringtone, which could not be heard by teachers if the phone rang during a class.
Nowadays, I have no idea if I can hear that whine anymore or not, as CRTs are quite uncommon. Probably not. Much for the better, as it used to give me headaches.
https://open.spotify.com/track/3B4q6KbHbGV51HO3GznBFF?si=Fgy...
https://open.spotify.com/track/6PsISpFaCEKwysPfwO9SfC?si=NQa...
(Or if these whines aren't CRT related, I'd be curious to learn the source).
Though it might be that since i really loved computers, i associated it with computers and liked it via association.
The dimensions of the cochlea are basically fixed at the time of birth. As the dimensions of the cochlea are the main contributing factor in what tones are able to be heard, the tonal bandwidths are then set at birth as well (minus hearing loss due to damage as we age). If you are interested in how sound is interperted by the brain, be aware that it is not a straightforward process and takes a bit of research. Still, the cochlea is essentially fixed at the time of birth.
More on how the dimensions of the cochlea determine tonal bandwidths: https://en.wikipedia.org/wiki/Hair_cell
[0] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3970226/
[1] http://www.ajnr.org/content/ajnr/early/2011/09/29/ajnr.A2713...
I'd be interested in hearing more about this. I understand the mechanism whereby audio sensitivity is progressively lost but I don't see why getting older would result in seeing fewer colors. Is this perhaps instead that we are less sensitive to color, requiring more photons to have the same color experience, but not actually seeing "fewer colors" in the sense that there are colors that fall off our gamut entirely? That would make sense to me.
As we age, we lose some hearing power and visual acuity, for physical reasons on the organs.
As our brains mature, they learn to not discrimate among certain "unimportant" sounds and colors. Adults can't lose the ability to disambiguate among novel language phonemes from foreign languages (as perfectly as kids can), and similarly they lose ability to distinguish similar colors that they learned are irrelevant. This isa tradeoff adaptation, so you can see a shadow gradient as single color instead of a complex spectrum, understand that traffic lights are showing the same signal despite variation in frequency, etc.
On another level, very small children (babies) have poor color vision, because their eyes and brains are still missing basic development.
So it's a curve: newborns have poor hearing and vision tha rapidly improves for a few years and then decays slowly, for both physical breakdown and for mental "optimization"