The human hand is incredibly good at seeing what's inside your pocket

Here's another: the human ear is phenomenal at determining where in 3d space a sound is coming from. Most animals can only determine direction and can't really place a sound vertically. Watch what your cat or dog does when they're looking for the source of a noise, it takes them a lot longer.
- I've heard that this is the reason dogs will tilt their head when looking curiously at something, as this lets them better differentiate sound positions vertically.
  
  I thought it was because their snout blocks their vision when they try to look downwards at something?
- the human *ears. we need both ears working together to determine the source of a sound.
  teamwork makes the dream work, people.
  
  https://en.m.wikipedia.org/wiki/Sound_localization
  If someone wants to read an interesting (but complex) explanation of how it works
- iirc it's because human ears are slightly offset to each other vertically. The brain then calculates the time difference it takes each ear to hear it. Basically triangulation.
  
  Triangulation is 2 dimensional, the 3 dimensional equivalent would be "tetrahedralization".
  
  I've never liked this explanation because if that was all there was to it, it would still only localize to a slanted line in front of us.
  Say for example the right ear is higher (I tried finding which one normally is, but couldn't find a good answer) in this case it would not be feasible without other clues to tell the difference between a sound being higher up and slightly to the left, or lower and slightly to the right. It's not a significantly different situation from the ears being the same height.
  In reality there are other clues, largely based on the shape of our ears slightly changing the sound in learned ways based on the angle it comes from.
  
  Wait what?
- One blindspot is that the ear is not good at determining whether the sound comes directly in front or back of the head.

Your tongue is also super tactile. We spend most of our toddler years discovering this.
You can look at anything around you, anything, and your brain knows exactly what it would be like to lick it, even if you've never done it before. Taste, texture, residue etc.. it's quite freaky
Oh and my thighs are really good at imagining my phone just buzzed.
- You can look at anything around you, anyrhing, and your brain knows exactly what it would be like to lick it
  Siri, how do I unthink a thought?
- Yeah, if you tilt your head back and pretend you're shaking a salt shaker into your mouth, you will actually taste salt.
  
  I don't taste anything. Does it matter how hard I shake it?
- When I was an adolescent, I dreamt that I performed oral sex on a woman by putting my entire head inside of her vagina. Turns out that cunnilingus is nothing like my premonition, but I certainly had the texture figured out.
  
  There are 100% women who would be into that. I'm not saying they're common, but I may have met at least one of them.
- You can look at anything around you, anyrhing, and your brain knows exactly what it would be like to lick it. Taste, texture, residue etc.. it's quite freaky
  my thighs
  Thanks... My body doesn’t really need sleep anyway.
  
  Creamy

As a single dude, I can tell You, that's not the only thing a human hand is good at.
- Dick, take a look out of starboard, it looks like a huge...

Also locating needed nightstand items in the dark of night
- I must have gotten a defective one, then. My hand sucks at that.

The area immediately before your hand is also really good at letting you know the time.

What's in my pocket?

Want to truly understand how good it is? Try getting a specific thing out of a pocket with a thick glove!

We're also the absolute best at throwing.

There are over 1 trillion nerve ending in your hand
Just kidding I made that up
- "And the average human only utilizes 10% of those nerve endings"

Wait y'all can pick the correct thing out of your pocket regularly? I'd say I have a 10-20% error rate. At least once a week I'm standing in front of the staff room door wondering why my car key is in my hand.

The brain is good at taking the information given it and creating a virtual image, including filling in missing parts. Both for touch and for the mention of hearing to calculate location. It can also be fooled because of this wiring, as it tries to find patterns where they may not exist.
- Your brain also has a model of the reality it’s interacting with. If the tactile sensation matches something in the library, that’s the image that gets pulled up.
  This system is far from perfect but usually it works pretty well. When it fails, you get false positives, illusions etc.

You can also scratch pretty much any part of your butt crack just by feel.
- With your hand.
  
  With your hand, right?

Idk... Sometimes I end up with nothing but keys in my hand and think I forgot my lighter just because the FOB for my car is the same shape and size as a BIC.

Too bad that my brain apparently still can't figure out the difference between they keys for my front door, shed and bike lock. Still requires 3 tries just like with USB sticks.
- Maybe you could apply different tapes or something to the keys to tell them apart.

I disagree, if my pocket is busy I need to take things out to tell the difference between them. Also, my hands can't tell the difference between my cards.
- I wonder if this is an acquired skill. I'm reminded of working on cars and having to build "touch sight" where you "see" things hidden behind an engine block or other obstruction by feel alone.

Exactly correct!

And human eyes are incredible at seeing things
- Human balls are incredibly great at feeling immense pain at even the slightest slap with a riding crop.

Then picking the exact correct thing
It can easily tell what item is a coin, but how much that coin is worth is hard for it to do. (Trying to grab a nickel vs a quarter, etc.)
_This _comment _is _licensed _under _CC _BY-NC-SA _4.0
- Euro coins have different knurling around the edge of the coin for accessibility reasons. It has the side effect of helping a lot when trying to find the right ones blindly in your pocket.
  
  US coins too. Big, small, thick, thin, smooth, knurled.
  
  Yeah I could definitely identify each euro coin by feel.
  
  Euro coins have different knurling around the edge of the coin for accessibility reasons. It has the side effect of helping a lot when trying to find the right ones blindly in your pocket.
  South America too, right?
  As an American, when I travel and see different shaped coins in different countries, some with holes in the middle even, just trips me out, seems so weird. We're so used to standard round feels similar coins here.
  _This _comment _is _licensed _under _CC _BY-NC-SA _4.0
- A nickel is smaller and thicker, and has a smooth edge compared to the quarter. Can you not tell the difference?
  
  This guy fishes in his pockets with his hands.
  
  A nickel is smaller and thicker, and has a smooth edge compared to the quarter. Can you not tell the difference?
  When you're jiggling around in your pocket for it and there's other coins in there too, it becomes harder to do.
  I'm not saying there's a 0% chance of figuring it out by touch alone, just that by touch identifying a coin (vs a not-coin) is a lot easier to do than by touch identifying what amount an individual coin is worth. (In the U.S. at least.)
  _This _comment _is _licensed _under _CC _BY-NC-SA _4.0