How Do Eyes Get Their Color?

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Paul Newman wasn't too fond of his blue eyes. The actor, who earned admiration from audiences and critics in everything from Cool Hand Luke to The Verdict, had a piercing set of blue irises that were as recognizable as Sylvester Stallone’s deltoids. He found the attention they received slightly grating. “If blue eyes are what it’s all about … I may as well turn in my union card right now and go into gardening,” the actor/philanthropist told The Saturday Evening Post in 1968.

If Newman knew the science behind his distinctive peepers, maybe he wouldn’t have been so hard on them. Although your genes are responsible for the color of your eyes, it’s a very complicated hereditary trait. Where you fall on the spectrum from light Newman blue to dark brown is the result of how much melanin pigmentation you have.

The iris—the colored part of the eye surrounding the pupil—is made of layers. The iris pigment epithelium is in the back and has some black or brown pigmentation to it. The layer over it is the stroma, which sometimes has brown melanin pigment, as well as colorless collagen. The black dots or “strings” you see in the eye are typically coming from the epithelium and are visible through the stroma.

Color is determined by the amount of melanin in the stroma. If you have brown eyes, you have brown melanin in the stroma that will absorb available light and make the iris appear darker in color. If you have green eyes, there’s not much melanin or collagen, and the light will be scattered. If your eyes are blue, you have no melanin at all—all of the light hitting the eye is scattered and reflected back. That’s why people with blue or green eyes can seem to shift eye color, depending on the amount of light in a room.

So how are genes involved? While they don’t directly program your body for a certain eye color, they do affect the quality and quantity of melanin in the stroma, which dictates your hue. While Newman’s brand of blue is a little more unusual than brown—the most common color—he probably would’ve been equally perturbed by grey. That shade, possibly caused by excess collagen, is considered the rarest eye color of all.

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Why Do We Eat Cranberry Sauce on Thanksgiving?

MSPhotographic/iStock via Getty Images
MSPhotographic/iStock via Getty Images

While plenty of people eat turkey, mashed potatoes, and pie year-round, it seems like cranberry sauce almost exclusively exists in the Thanksgiving universe. Although we don’t know for sure whether it was eaten at the very first Thanksgiving, the jiggly, gelatinous side dish does have deep roots in the history of America’s fruited plains.

According to Insider, cranberries are one of only three commercially grown fruits native to the United States, and the Wampanoag tribe had been using them for food, dye, and medicine long before feasting with the Pilgrims in 1621. If there were cranberries at the party, they probably didn’t taste much like the sweetened sauce we’re (circumstantially) fond of today; at that point, the settlers hadn’t yet succeeded in growing sugar cane in the New World.

But a little more than 50 years later, according to a 1672 account cited by The Washington Post, the new Americans and Native Americans had both started to enjoy cranberries much like we do at Thanksgiving dinner: “Indians and English use it much, boyling them with Sugar for a Sauce to eat with their Meat.”

In 1796, Amelia Simmons—author of American Cookery, the first-ever American cookbook—took it one step further by recommending that roast turkey be served with cranberry sauce. Considering that the Library of Congress included the book on its list of “Books That Shaped America,” it’s possible that Simmons’s suggestion reverberated through kitchens across the nation, and the tradition gained momentum from there. She does mention pickled mangoes as an alternate side dish for turkey, but the then-Indian import was likely less common than the locally-grown cranberry.

Then, in the early 1800s, Ocean Spray revolutionized the labor-intensive process of hand-picking cranberries from vines with what’s called a wet harvest. Basically, farmers flood the bogs where cranberries grow, and then they wade into the water to collect the floating berries en masse.

farmer wet-harvesting cranberries
A farmer gathering cranberries during a wet harvest.
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This was a more efficient technique, but a mass harvest meant that more cranberries got damaged. So in 1912, Ocean Spray began crushing them into canned, jellied cranberry sauce—maximizing the yield and making it easier than ever for every home in America to slice up a cylinder of solid, sugary, berry goodness.

Explore the stories behind your other favorite (or least favorite) Thanksgiving foods here.

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Why Do We Eat Pumpkin Pie at Thanksgiving?

gjohnstonphoto/iStock via Getty Images
gjohnstonphoto/iStock via Getty Images

While it’s possible—even probable—that pumpkins were served at the 1621 harvest festival that’s now considered the predecessor to Thanksgiving, attendees definitely didn’t dine on pumpkin pie (there was no butter or wheat flour to make crust).

The earliest known recipes for pumpkin pie actually come from 17th-century Europe. Pumpkins, like potatoes and tomatoes, were first introduced to Europe in the Columbian Exchange, but Europeans were more comfortable cooking with pumpkins because they were similar to their native gourds.

By the 18th century, however, Europeans on the whole lost interest in pumpkin pie. According to HowStuffWorks, Europeans began to prefer apple, pear, and quince pies, which they perceived as more sophisticated. But at the same time pumpkin pie was losing favor in Europe, it was gaining true staple status in America.

In 1796, Amelia Simmons published American Cookery, the first cookbook written and published in the New World colonies. Simmons included two recipes for “pompkin pudding” cooked in pastry crust. Simmons’s recipes call for “stewed and strained” pumpkin, combined with a mixture of nutmeg, allspice, and ginger (yes, it seems our pumpkin spice obsession dates back to at least the 1500s).

But how did pumpkin pie become so irrevocably tied with the Thanksgiving holiday? That has everything to do with Sarah Josepha Hale, a New Hampshire-born writer and editor who is often called the “Godmother of Thanksgiving.” In her 1827 abolitionist novel Northwood, Hale described a Thanksgiving meal complete with “fried chicken floating in gravy,” broiled ham, wheat bread, cranberry sauce, and—of course—pumpkin pie. For more than 30 years, Hale advocated for Thanksgiving to become a national holiday, writing regular editorials and sending letters to five American presidents. Thanksgiving was a symbol for unity in an increasingly divided country, she argued [PDF].

Abraham Lincoln eventually declared Thanksgiving a national holiday in 1863 (to near-immediate outcry from Southerners, who viewed the holiday as an attempt to enforce Yankee values). Southern governors reluctantly complied with the presidential proclamation, but cooks in the South developed their own unique regional traditions. In the South, sweet potato pie quickly became more popular than New England’s pumpkin pie (mostly because sweet potatoes were easier to come by than pumpkins). Now, pumpkin pie reigns supreme as the most popular holiday pie across most of the United States, although the Northeast prefers apple and the South is split between apple and pecan, another Southern staple.

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