Cartoon prototypes
In The Conlanger's Lexipedia, Mark Rosenfelder (Zompist) writes: "(I might add that if you ask a cartoonist to draw it, they’ll probably draw the prototype. From this we can learn that the prototypical hunk of cheese is Swiss, with really big holes.)"
Taking on this, here are the cartoon prototypes -- the way a typical member of various types of things or people is stereotypically drawn -- for many nouns.
Foods
Cheese
A hunk of Swiss cheese, with big holes
Apple
A bright red apple, probably a Red Delicious, with long stem and sometimes a worm
Ice cream
A perfectly conical, hatched cone with big scoops of vanilla ice cream on top
Pizza
A circle of cheese and red pepperoni pizza, with one slice being taken out
Hamburger
Tall, has a sesame seed bun with lettuce and tomatoes decked around the patty
Taco
Hard-shelled, with cheese, lettuce, tomatoes, and beef
Sushi
A squircular piece of shiny, white rice with pink ambiguous seafood inside
Grocery bag
Always has a loaf of French bread sticking out
Vehicles
Airplane
Plump and white, with a big puffy contrail coming out the back
Car
Bright red, fast
Noah's Ark
A brown wooden boat (not a box as in the Bible), with animals sticking their heads out of the windows and some on the deck; giraffes and elephants will ALWAYS be present
Clothes
Pajamas
Vertical red and white stripes
Animals
Bird
Songbird perching and singing a song
Monkey
Brown, hangs from tree by versatile tail, funny/jocular expression on face
Cow
A Holstein cow, with cowbell
Horse
Brown with a black mane
Dinosaur
A big, green sauropod
Pig
Peach-like pink color, little hair, has some mud on it in which it rolled around
People
Baby
In diaper, big head, pink skin, one tooth, little hair, hairbow if a girl, crying loudly
Boy (child)
Blue eyes, red-and-white-striped T-shirt, blue jeans, sneakers, baseball cap, a little on the fat side
Girl (child)
Blonde hair in pigtails, blue eyes, pink dress, carries doll or teddy
Boy (teenage)
Brown hair is loose and messy, blue eyes, freckles, either a red-and-white-striped T-shirt or a polo with green and blue stripes or blue with one thick white stripe across the middle, skinny
Girl (teenage)
Blonde hair in ponytail, blue eyes, freckles, pink sweatshirt, blue jeans, prominent breasts
Young man (twentysomething)
Black hair, beard, black clothes, looks like a millennial hipster
Young woman (twentysomething)
Blonde hair in ponytail, physically fit, black tank top, prominent breasts
Doctor
Wears band with circle over head and lab coat, carries either stethoscope or tube of miracle medicine
Pirate
Jolly Roger cap, eye patch, red-and-white-striped T-shirt, hook for hand, peg leg, parrot on shoulder, beard
Burglar
Long-sleeved shirt with horizontal stripes, raccoon-like mask over eyes, carries a bag with a dollar sign on it
Basketball player
Very tall, African-American, good-looking, wears shorts and numbered tank top in matching colors
Quarterback
White male, large hunk build, wears shoulder pads, numbered football uniform, golden smile, princely good looks
Soccer player (male)
Hispanic, physically fit and energetic-looking, shiny black hair, dressed in team's colors
Soccer player (female)
Shiny black hair in ponytail, physically fit and energetic-looking, dressed in team's colors
Tennis player
Black hair, head band, polo shirt and preppy clothes, thin, ponytail if female
Baseball player
Vertically striped button-up shirt, forward-facing baseball cap, eager look on face that evinces an "in it to win it" spirit, in shape but neither short nor tall
Scientist
Older Caucasian (usually White but often Jewish) male with messy white hair, unkempt appearance, white lab coat, glasses
