Earlids ... maybe possible
Dennis Miller, semi-joking about the modern Grievance Police and Rainbowshirts, says that evolution needs to provide a solution: Earlids. If we can close our ears as easily as we close our eyes, we could avoid things that will bother us.
Of course it wouldn't really solve the Rainbowshirt problem, because these tyrants don't want to close their ears. They create grievances and lawsuits from statements that are completely innocent and inoffensive. They go out of their way to find ordinary speech that can be pivoted into censorship and blackmail.
help normal people who have normal sensitivities. We could then block out whatever bothers us: commercials, buzzkills, rock-n-roll, classical, Breaking News, Fox, CNN, etc.
We probably don't need 'evolution'. We already have the mechanism in our middle ear, and it might
be possible to make its action more voluntary. With sufficient practice and exercise, it could
become a useful damper if not a complete earlid.
This is a crude animation of the middle ear action. Sound hits the (red) eardrum, moves the three little bones, and pushes on the fluid in the cochlea. The (beigish) muscle coming out into the foreground is the Tensor Tympani. It attaches onto the other side of the middle ear chamber. When it tenses, it sort of 'jams' the bearings of the ossicles, making movement harder.
Normally the Tensor Tympani acts involuntarily when a loud sound is perceived. But all involuntary muscles can be controlled voluntarily
with sufficient practice.
Voluntary muscles are equipped with a beautifully complete set of built-in feedback sensors for bend, stretch, and acceleration. We know without any special mental effort when a finger is bent halfway. Involuntary muscles lack those sensors, so you have to find an indirect feedback indication and then screw around with various 'efforts' until you pick up the feedback.
For a nearby example, I learned a long time ago how to open my Eustachian tubes to pop each ear, without any visible action like yawning or chewing. The pop was the feedback, and I just kept 'throwing' effort into various 'places' until the pop happened. Now I can do it on command, almost as precisely as bending a finger.
Many people are able to control vasodilator muscles by monitoring the sense of warmth in the extremity when the arteries are open.
For the TT, the obvious signal would be a damping of steady sound input. Another possible learning path: The TT always
tenses when you talk, because your own voice in such close quarters can be strong enough to damage your cochleas. Sometimes when I'm tired or sleepless, with inhibitory mechanisms presumably weakened, I can actually hear the TT acting with a 'thump' when I vocalize.
If you can master tightening and holding the TT, you'll have earlids.