
Proprioception: The Silent “Sixth” Sense - blairh313
https://www.vox.com/the-highlight/2019/11/22/20920762/proprioception-sixth-sense
======
pacaro
The way we learn about the five senses in elementary school bugs me. It is
presented as this absolute fact and has become completely culturally embedded.

Some may argue proprioception is provided by touch, but by the same light
smell and taste are inextricably linked.

We can also sense heat and humidity to some extent, we have some of the
mechanisms needed to sense magnetic fields, but no compelling evidence (to my
understanding) exists that demonstrates that we can.

It's just one of those things thats much fuzzier than we think

Many things that we are taught in elementary school have this property

~~~
wongarsu
Even "touch" as a sense makes no sense. Feeling pressure and feeling heat
exchange are completely different senses. In addition to that there's
obviously a kind of pain felt by the skin that is neither extreme pressure nor
a temperature extreme but an indicator of skin damage.

Then there's proprioception as mentioned in the article, the sense of
balance/acceleration as measured in our ears, and together with smell, sound,
taste and sight we are already at 9 senses.

And as you mention many of the things we actually perceive are derived from
many senses. The "taste" of a steak is a mix of smell and taste, your balance
is a mix of sight and your acceleration, temperature is something we can't
actually fell but can derive from how much heat enters or leaves our body,
"pain" is a giant category spanning nearly all senses, etc.

~~~
soulofmischief
We also have speed cells, boundary cells, place cells, grid cells... some of
our senses might not be auxiliary or primary but rely on another sense which
mediates them.

But your body keeps track of its speed and location in any environment
regardless of if your senses are impaired (grid cells and place cells rely not
only on sight but information gathered from speed and head direction cells),
which is as much of a sense as proprioception. We don't even have a word for
this, I think. Locoception, perhaps? Posiception? Only two Latin roots I know
which fit.

[https://en.wikipedia.org/wiki/Grid_cell](https://en.wikipedia.org/wiki/Grid_cell)

[https://en.wikipedia.org/wiki/Place_cell](https://en.wikipedia.org/wiki/Place_cell)

[https://en.wikipedia.org/wiki/Speed_cells](https://en.wikipedia.org/wiki/Speed_cells)

[https://en.wikipedia.org/wiki/Boundary_cell](https://en.wikipedia.org/wiki/Boundary_cell)

~~~
byteface
"We don't even have a word for this". Isn't it just spatial frequency?

~~~
soulofmischief
The innate sense of where you are in relation to yourself is proprioception.

The innate sense of where you are in relation to your environment is...
spatial frequency?

That doesn't sound right.

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shpx
> Humans have more than the commonly cited five senses. The number of senses
> in various categorizations ranges from five to more than 20. In addition to
> sight, smell, taste, touch, and hearing, which were the senses identified by
> Aristotle, humans can sense balance and acceleration (equilibrioception),
> pain (nociception), body and limb position (proprioception or kinesthetic
> sense), and relative temperature (thermoception). Other senses sometimes
> identified are the sense of time, echolocation, itching, pressure, hunger,
> thirst, fullness of the stomach, need to urinate, need to defecate, and
> blood carbon dioxide (CO₂) levels.

[https://en.wikipedia.org/wiki/List_of_common_misconceptions#...](https://en.wikipedia.org/wiki/List_of_common_misconceptions#Senses)

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hash872
I think proprioception is also part of the secret to 'athleticism', which is
kind of a vague hand-wavey concept but also a very real one (speaking as
someone with no natural athleticism myself). Being able to intuitively
understand where your body is in space & how to react/move it in the moment is
a hidden part of being an athlete, whereas conventional analysis usually just
focuses on strength/speed/explosiveness.

I also think there's a very strong cognitive/information processing in the
moment aspect to athleticism as well- a general CPU motor that coordinates the
speed, strength, proprioception etc. together in the moment. (Another aspect
that I noticed I lacked growing up compared to others in sports)

~~~
hoorayimhelping
I don't think it's a hidden skill in the context of sports, because it's a
baseline that almost every athlete has.

I think it's a huge myth to think of athleticism as a talent and not a skill
that can be trained. It's absolutely a skill - my wife was pretty
uncoordinated when we met - she never really played much sport or did many
outdoorsy activities. She just assumed she was uncoordinated, but after about
a year of lifting weights, she's found that her balance and coordination have
improved tremendously. She doesn't stumble when walking as much, she's better
at doing things like catching stuff out of the air, and she's more aware of
where her body is in space - she doesn't bump into things as much.

~~~
hash872
Athleticism is absolutely an inborn talent. It certainly can be developed, but
just look at any sport where all of the participants started at the same age
in life and all received roughly the same number of repetitions/practices-
there are logarithmic differences in ability. If we all started playing
basketball at age 7 and all went to the same number of practices, by 18 there
are just massive, massive differences between different players.

Frankly, this is true of literally every field. Like, imagine we all started
in programming at age 10 and all received the same level of instruction- by
age 20 there are again just huge, huge differences between where people are at
ability-wise. It's unfair and doesn't fit into a lot of meritocratic 'just
work hard and you'll end up at the top!' narratives (which are especially
popular in the US), but it's sadly true

~~~
InitialLastName
> If we all started playing basketball at age 7 and all went > to the same
> number of practices, by 18 there are just > massive, massive differences
> between different players.

Those differences come from a lot of places, not least that the people who
ended up on the better end of the stick almost certainly found every
opportunity they could to play basketball outside of practice.

My sister and I both played sports and learned about computers in school. She
spent lots of her spare time after school and on weekends shooting baskets in
the driveway. I spent that time messing around on computers and taking things
apart. Any guesses which of us ended up the better athlete and which the
better engineer?

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sixstringtheory
reminds me of a story in “the man who mistook his wife for a hat” by Oliver
Sacks, an amazing collection of harrowing psychological tales, where one of
his patients–a computer programmer!–has a dream where she can no longer
control her limbs, and when she wakes it has somehow come true.

[https://www.litcharts.com/lit/the-man-who-mistook-his-
wife-f...](https://www.litcharts.com/lit/the-man-who-mistook-his-wife-for-a-
hat/part-1-chapter-3-the-disembodied-lady)

~~~
newman8r
Did anyone figure out why this happened? I wonder if this would feel similar
to when you sit awkwardly and your leg goes numb - it kind of feels like
you're just walking on your bone. Trying to walk with a leg that's 'asleep' is
quite a challenge.

~~~
AnimalMuppet
I used to have that. It seems that it was the cat, laying on top of the
covers. I would try to move in my sleep and be unable to, because I was moving
with very little force, and it wasn't enough to overcome the cat. But I'd feel
this as my limbs not responding to me. What a horrible feeling!

It quit happening to me once the cat died.

~~~
calibas
Sounds like sleep paralysis:
[https://en.wikipedia.org/wiki/Sleep_paralysis](https://en.wikipedia.org/wiki/Sleep_paralysis)

Happened to me a couple times, but it's been like 15 years since.

~~~
newman8r
Happened to me a ton as a kid. Now maybe I only get it once every few years. A
long time ago I learned I could 'exit' sleep paralysis, and after that I
actually began to enjoy it and not try to immediately exit it - it's like
lucid dreaming but you're totally aware of the world around you.

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antisocial
I recently stumbled on painscience.com blog. It is a great resource to
understand pain and be able to live with it.

[https://www.painscience.com/articles/central-
sensitization.p...](https://www.painscience.com/articles/central-
sensitization.php)

Physical therapy involves a lot of proprioception retraining that is lost due
to injury, surgery or inactivity.

[https://www.painscience.com/articles/sixth-
sense.php](https://www.painscience.com/articles/sixth-sense.php)

------
theothermkn
I made a minor personal discovery recently along these lines and would love to
hear from others here if they can reproduce it: I can "see" my hands with my
eyes closed. That is, if I hold my hands out in front of my face with my eyes
closed, I can see a faint image of them in the eigengrau. Further, if I then
move my hands outside of my normal field of vision, (say, to my side) the
image persists; I can "see" them outside my normal field of vision. While this
effect is strongest for my hands, it does extend somewhat to my legs and feet
if I pay extra attention.

I'm curious if others can reproduce this for themselves?

My hypothesis is that the visual areas of the brain can get involved when the
eyes are closed, and can pick up and interpret the proprioceptive information
spatially. It may be that it's always happening, but that the "image" of one's
hands is swamped by visual data when the eyes are open. Another hypothesis, I
suppose, is that the visual expectation of the hands may be registering or,
rather, its absence. You're "seeing" the expectation of the hands that should
be there, but are blocked by your eyelids.

I should say that the sensation of seeing the hands is pretty fine, extending
to the motions of the fingers. That said, it's easy enough to lose the image
or forget it is there.

~~~
t0mas88
Funny, a few comments above, before reading yours I experienced exactly that.

I closed my eyes in the dark and tried to touch my two index fingers together
in random places instead of just pointing at my nose. Can confirm that I also
"see" the position of hands and fingers.

I think what we "see" is mostly out brains doing spatial reasoning and using
part of the same systems as used for visual perception.

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chadlavi
is proprioception really a sense or just the persistence of spatial info in
our short term memory gathered from our senses of touch and sight? If I touch
something several times with my eyes open then try it with my eyes closed, I
can touch it again because I still remember where it was.

Is there some way a human can be said to propriocept things that they neither
saw nor touched?

~~~
ThrustVectoring
_All_ your senses are constructed out of more basic sensory inputs and
presented to the rest of your brain as higher-level abstractions. Hearing, for
example, doesn't just present the raw noises being heard, but also yields a
best-guess about the direction and distance of noise sources, and you can
argue that the audio-location function should technically be a separate
"sense".

Proprioception being an abstraction over touch and sight data that generates
awareness of how your body is arranged in space is a sense in the same manner.
And you can definitely get proprioception over more than your own body -
partner dancers will _quickly_ develop a felt sense of how their dance
partner's body is moving, as well.

~~~
aurelianito
As a tango dancer I can relate to feeling the position of my partner while
dancing. Even weirder is that I can feel my car while driving and if I rent
another car it takes me a while until I can also feel this other car as a part
of myself.

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pmoriarty
_" The feeling is as hard to imagine as it is to describe. "It's as if you had
a blindfold and somebody turned you several times, and then you're asked to go
in a direction. The first few seconds, you don't know what direction you're
going in." Pure disorientation."_

I think might other ways to approximate this. Try lying completely still in
bed at night in the dark for 10 minutes or so... after a while you might have
trouble knowing exactly how your limbs are positioned (unless, of course, you
make a mental note of just how they were positioned when you first laid down,
or kept your attention focused on that all along, but if you think of
something else, then ten minutes later think about the position of your limbs,
you might have trouble). The key in the above exercise is not feeling anything
in your limbs that could give you a cluse as to where they're positioned. This
makes me wonder if we need some kind of periodic kinesthetic or viseo-
kinesthetic calibration to keep our sense of proprioception functioning well.

Psychedelic drugs could also impact our sense of proprioception, as they can
just about everything else about our experience. Being in a floation/isolation
tank could likewise affect it.

Something else I wonder about lack of proprioception is at all related to the
problem some people have of telling right from left.

------
leemck
The article title and headline sentence confuse the reader.

Proprioception is an interesting and exciting mental process that is important
to artistic expression, human growth, mental development, and cultural
communication.

Whew. The opera "Nixon in China" has an embedded ballet. The embedded ballet
has the uncanny property that in a few minutes it retells the entire story of
the opera.

Why is ballet so expressive? Why does the nation of Russia need ballet? Notice
on youtube, the Russian dancers are extraordinary. A prima ballerina who came
to New York, drew comments that "She dances in Russian." And the untutored
viewer could see it too. The nation devotes considerable resources to the art.

What is happening when 1st through 5th graders in an American Elementary
school run around and scream at the beginning of the school year? Were they
running around to generate huge amounts of propriaceptive signals to the
brain? Is the screaming part of the brain sending motor control signals every
which way?

Finally, why do opera singers stand up to sing? Except when they are dying or
portraying a special propriaceptive statement like kneeling (to pray or be
beheaded).

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khazhoux
Try this fun experiment yourself:

On some long sidewalk (with no hazards on either side) or on a field, find any
visible point 20-30 feet straight ahead of you, like a crack in the sidewalk
or a leaf, whatever. Now look at it for just a moment (only takes a second or
two to imprint its location) and close your eyes. Start walking towards that
spot (no peeking), and stop when you think your foot is over the target. You
will be shocked at how accurately you estimated the walking distance, and how
your body very strongly senses when you've reached the spot. Almost 10 out of
10 times, my foot is perfectly centered over the target (modulo some lateral
movement from not walking perfectly straight).

For me, I can somehow "physically" feel when it's close, I can feel when I'm
over it, and I can feel when I've gone too far.

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ghaff
Alcohol throws off proprioception, which is why it's tested for as part of
field sobriety tests, e.g. touch your finger to your nose. Similar decreased
capabilities are also one of the reasons why someone getting hypothermic will
often start to have an unsteady gait.

~~~
hinkley
I had to re-learn my alcohol limit a few years into martial arts. Turns out I
was using the decline of proprioception as a marker for 'last beverage' and
the training pushed that to the right. Got a few hangovers before I sorted it
out.

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elil17
Much like optical illusions, there are proprioceptive illusions. The simplest
yet most amazing to me is the rubber hand illusion, where you can trick your
brain into feeling proprioception of an inanimate object. I highly encourage
you to find a friend and try it out:

[https://en.wikipedia.org/wiki/Body_transfer_illusion#Rubber_...](https://en.wikipedia.org/wiki/Body_transfer_illusion#Rubber_hand_illusion)

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christopoulos
I find this interesting as I had a somewhat opposite experience when I tried a
dark restaurant when visiting Berlin (eating in complete darkness). It was
surprisingly rest to relocate utensils and my glass of beer, as I went back
and forth between them, stopping and raining to eat.

Of course, the room wasn’t empty and void other sounds, which may have helped
me build a general sense of direction and thereby helped me.

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woodandsteel
This is a fascinating article. I never realized all the complications involved
in propriception and touch.

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lostmsu
TL;DR; people with reduced sense of touch have major troubles controlling
their bodies unless they see them (own interpretation: due to the lack of
feedback on movement). There is a rare genetic condition.

There is no other sense involved, it is the same touch sense, but internal.

