Goosebumps, blushing, wrinkling, marks, spots, and hair.
15 oddities. 7 have this as their primary region.
A pleasant tingling that starts on the scalp and moves down the neck and spine, set off by whispering, tapping, soft sounds, or gentle personal attention. Not everyone gets it. A large online community is built around it.
Some earlobes hang free and others join the head directly. Textbooks taught this as one gene, but a 2017 study found at least 49 genetic regions involved, and the two shapes blend into each other.
When you are embarrassed, blood vessels in the face open wide and the skin turns red. You cannot stop it. Darwin called it the most human of all expressions, and no other animal seems to do it.
In a few people, a firm stroke on the skin raises a red welt within minutes, clear enough to write words with a fingernail. It is the skin's hive response set on a hair trigger.
A second row of eyelashes growing from the oil-gland openings along the inner edge of the eyelid. It is rare, mostly inherited, and Elizabeth Taylor was born with it.
Turning the upper eyelid inside out so the pink inner surface shows. Most people with reasonably loose lids can learn it. Eye doctors do it to patients to look for grit.
Tiny pale yellow or white bumps, 1 to 3 mm across, on the edge of the lips or inside the cheeks. They are ordinary oil glands in a place without hair. Most adults have them.
Goosebumps and a wave of chills down the back at a powerful moment in music, a film, or a speech. About half of people get it regularly. It comes from the brain's reward system reacting to an expectation being met or broken.
Tiny muscles at the base of every hair pull the hair upright when you are cold, scared, or moved. In a furry animal this traps warm air or makes it look bigger. In a human it does almost nothing.
A tiny hole in the skin just in front of the ear, present from birth, that leads to a short blind tunnel. It is harmless unless it gets infected.
Fingertips and toes wrinkle after 5 to 15 minutes in water. This is not the skin soaking up water. It is the nervous system shrinking the fingertip on purpose, and the wrinkles may improve grip when wet.
Lifting a single eyebrow while the other stays down. Between 30% and 35% of people can do it without training. Most of the rest can learn it in front of a mirror.
An extra nipple, usually small and flat, on a line running from the armpit to the groin. Between 1 in 500 and 1 in 18 people have one, and most think it is a mole.
Giving yourself goosebumps on command, without music, cold, or fear. About 1 in 1,500 people can do it. The muscles involved are not supposed to take orders.
Two toes joined by skin, most often the second and third, in about 1 in 2,000 to 3,000 babies. The toes usually work normally and many people leave them as they are.