Brain Trick
Ambidexterity
Using both hands equally well for every task. About 1% of people are truly ambidextrous. Many people who say they are ambidextrous are mixed-handed: right hand for some jobs, left for others.
About 1%
Trick
Things some people can do on command. Some are learnable; others appear to be innate.
Showing 26 oddities.
A trick is something a person does on purpose, on command, that most other people cannot do at will. Tongue rolling, ear wiggling, and crossing your eyes all belong here because someone can start and stop them whenever they like.
You can tell a trick from other kinds by asking one question: does the person choose when it happens. A reflex fires on its own when triggered. A trick fires when the person decides to show it off.
The boundary gets blurry with things like voluntary piloerection, giving yourself goosebumps without cold or fear. The muscle involved normally answers only to a reflex, not to instructions. What makes it a trick, and not a reflex, is that a small number of people have found a way to give it orders anyway.
Results narrow the list below as you type.
Mouth Trick
Cloverleaf tongue
Folding the tongue into three lobes, like a clover leaf. In one Dutch study, about 15% of adults could do it. It is usually called the hardest tongue shape.
About 15% (one Dutch sample)
Eyes Trick
Crossing your eyes
Turning both eyes inward toward the nose on purpose. Most people with normal two-eyed vision can do it. Your eyes will not get stuck that way.
Most people (no formal count)
Ears Trick
Ear rumbling
Up to about half of all people can make a low roar inside their own head by tensing a tiny muscle in the middle ear.
43–55% of people
Ears Trick
Ear wiggling
Moving the outer ears using three small muscles that most mammals use to point their ears at sounds. About 1 in 5 people can wiggle their ears. Some people can learn.
About 1 in 5
Eyes Trick
Eyelid flipping
Turning the upper eyelid inside out so the pink inner surface shows. Nobody has counted how many people can do it. Eye doctors do it to patients to look for grit.
No formal count Icky
Muscle Trick
Flaring your nostrils
Widening the nostrils on purpose. No study has counted how many people can do it on command. It also happens on its own during hard breathing and in strong emotion such as anger.
No formal count
Mouth Trick
Gleeking
Shooting a thin jet of saliva from under the tongue. It can happen by accident, often during a yawn, or on purpose. No survey has counted how many people can do it.
No formal count Icky
Mouth Trick
Gorlin's sign
Touching the tip of your nose with your tongue. About 10% of people can do it. About half of people with Ehlers-Danlos syndrome can, so doctors use it as a quick check for stretchy connective tissue.
~10% of people Icky
Heart Trick
Heart rate control
Slowing or speeding up your own heartbeat on purpose, using breath, attention, or training. Breathing can shift it a little within minutes. A few trained people shift it a lot.
No formal count
Eyes Trick
Independent eye movement
Moving one eye while the other stays still, or moving the two eyes in different directions. Few people seem to manage it, and nobody has counted them. Chameleons do it all day.
No formal count
Bones Trick
Knuckle cracking
Pulling or bending a finger joint until it pops. Between 25% and 54% of people do it out of habit. The pop comes from a gas bubble in the joint fluid, and it does not cause arthritis.
25–54% crack habitually
Bones Trick
Midtarsal break
A foot that bends in the middle, between the heel and the ball, as well as at the toes. About 1 in 12 people have it. It looks like the midfoot bend of apes.
About 1 in 12 (8%)
Muscle Trick
Platysma display
Tensing the thin sheet of muscle under the skin of the neck so that cords stand out from jaw to collarbone. Everyone has the muscle. Nobody has counted how many can flex it on its own.
No formal count
Mouth Trick
Pointed tongue
Making the tip of the tongue narrow and sharp, like a pencil point. About 55% of people in one Chinese survey can do it. It and tongue rolling are the two most common tongue tricks.
~55%
Muscle Trick
Raising one eyebrow
Lifting a single eyebrow while the other stays down. Informal estimates say 30% to 35% of people can do it without training. No study has measured how many of the rest can learn it.
30–35%
Mouth Trick
Tongue folding
Folding the tip of the tongue backward over itself inside the mouth. Studies find that between 1.5% and 27.5% of people can do it.
1.5–27.5%
Mouth Trick
Tongue rolling
Between 65% and 84% of people can curl the sides of the tongue up into a tube. For decades it was taught as a simple one-gene trait. It is not.
65–84% of people
Mouth Trick
Tongue twisting
Turning the tongue on its side so the edges face up and down, or all the way over. Between 12% and 36% of people can twist it at least halfway.
12–36%
Organs Trick
Voluntary burping
Swallowing air on purpose and letting it back up as a belch. Nobody has counted how many people can do it. The loudest recorded burp reached 112.4 decibels.
No formal count
Ears Trick
Voluntary Eustachian tube opening
Opening the tubes that link the middle ear to the throat on command, without swallowing or pinching your nose. You hear a click, and your own voice gets loud. Some divers and freedivers learn it, but most never do.
No formal count
Bones Trick
Voluntary joint dislocation
Pushing a joint partly or fully out of its socket on purpose, then back in. Between 10% and 25% of people have some joint hypermobility. One survey of students and their siblings found 0.5% to 2.6% could dislocate a shoulder at will.
0.5–2.6% (shoulder, one survey) Icky
Eyes Trick
Voluntary nystagmus
About 8% of people can make both eyes shake rapidly from side to side on command. It looks alarming and is harmless. It is tiring and lasts only seconds.
About 8% of people
Skin Trick
Voluntary piloerection
Giving yourself goosebumps on command, without music, cold, or fear. Nobody knows how many people can do it, but it seems rare. The muscles involved are not supposed to take orders.
Unknown, but rare
Eyes Trick
Voluntary pupil control
Changing the size of your pupils by will alone, without imagining a light or doing sums. One case has been studied with modern methods. Older reports exist, but most describe indirect tricks. Indirect control by thinking hard is possible for almost everyone.
One modern case study. No rate known
Eyes Trick
Wall-eyed divergence
Turning both eyes outward, away from the nose, on purpose. Nobody has counted how many people can do it. Most people can learn the mild version, parallel viewing, from Magic Eye pictures.
Not known