The Reason Why Stop Signs Are Red

Roman_Gorielov, iStock/Getty Images Plus
Roman_Gorielov, iStock/Getty Images Plus

Why is red the standard color for stop signs? The short answer is this: because the representatives of the First National Conference on Street and Highway Safety in 1924 decided so.

Though stop signs were still a relatively new idea in the United States back in the 1920s—Detroit erected the first one around 1915, Jalopnik reports—the “red means ‘stop’” custom dates back to 1841, when Henry Booth of the Liverpool and Manchester Railway suggested using red to indicate danger on railroads. London then adopted the color for its regular traffic lights in 1868, and the United States eventually followed suit.

The First National Conference on Street and Highway Safety, called by then-Secretary of Commerce Herbert Hoover in 1924, aimed to standardize the color coding of road signage. It established that for all “signs and signals, both luminous and nonluminous,” red should indicate “stop,” green should indicate “proceed,” and yellow should indicate “caution,” according to the report released after the conference [PDF]. It was also decided that distance and direction signs should be black and white.

That all probably sounds familiar if you’ve ever seen a street before, but implementing the mandate for red stop signs posed immediate issues. A red material that wouldn’t fade over time just didn’t exist in 1924, Gene Hawkins, a professor of civil engineering at Texas A&M University, told The New York Times in 2011. So the writers of the 1935 Manual on Uniform Traffic Control Devices chose the next best thing: yellow. The manual also specified that every sign should be octagonal, another idea from the 1920s.

California was first to figure out that porcelain enamel would resist fading and erect red stop signs across the state, a practice noticed and addressed in the 1954 revision [PDF] to the Manual on Uniform Traffic Control Devices. Now that red was more logistically feasible, the committee in charge of updating the manual decided there should be no more yellow stop signs.

We don’t know exactly why Henry Booth and other early industrialists felt that red aptly signaled “stop.” Maybe they thought it was harder to overlook than blue or green, which natural surroundings like water and foliage might easily camouflage. Maybe they felt red, like fire or blood, just went along well with danger.

There may also be a deeper reason. When, as part of a 2011 study, red-, blue-, and green-clad human experimenters offered apple slices to individual monkeys in a free-range facility, the monkeys seemed to have an aversion to taking slices left by the experimenter wearing red. Perhaps our association of danger with the color red has a psychological basis we don’t fully understand yet.

[h/t Jalopnik]

The Reason Dogs Twitch in Their Sleep

Tetiana Garkusha/iStock via Getty Images
Tetiana Garkusha/iStock via Getty Images

The sight of a dog batting its tiny paws around while sleeping is irrefutably adorable, and it’s not hard to imagine that your beloved pet is dreaming of swimming, fetching a Frisbee, or bounding around the yard in pursuit of a scampering squirrel.

In truth, that’s pretty much exactly what’s going on. Dogs, like humans, dream during the REM cycle of sleep, and their twitches are responses to whatever’s happening in those dreams. Though all dogs can exhibit muscle movements while dreaming, PetMD reports that it most often affects younger and older dogs. This is because of the pons, a part of the brainstem with two “off” switches that regulate movement during the sleep cycle.

“If either or both of these ‘off’ switches is not fully developed or has grown weak due to the aging process, then the muscles are not completely turned off and during dreaming, the animal will start to move,” Stanley Coren, a neuropsychological researcher and former psychology professor at the University of British Columbia, told PetMD. “How much movement occurs depends upon how effective or ineffective these ‘off’ switches are.”

As long as your dog looks like it’s having a grand old time in its dreams, you can sit back and enjoy the show. If you think your dog might be having a nightmare, be careful about waking it up. As the American Kennel Club (AKC) explains, a dog woken abruptly from a bad dream might bite you before it realizes its distress wasn’t real.

You should, however, learn to recognize the difference between a normal dream and a seizure.

“Some [dogs] manifest dreaming with twitching, paddling, or kicks of the legs. These movements are often brief (less than 30 seconds) and intermittent,” Jerry Klein, the AKC’s chief veterinary officer, described on the AKC website. “Seizing dogs’ limbs, on the other hand, tend to be rigid and stiffer, with more violent movement.”

The seizure can also be accompanied by loss of bowel control. If that description sounds familiar, you should talk to your veterinarian.

[h/t PetMD]

The Reason Doctors Have Such Sloppy Handwriting

Rostislav_Sedlacek/iStock via Getty Images
Rostislav_Sedlacek/iStock via Getty Images

It seems counterintuitive that doctors—widely regarded as some of the smartest, most detail-oriented people out there—so often have horrible handwriting. From a patient’s standpoint, it could seem downright terrifying. If your pharmacist misinterprets your trusted physician’s chicken scratch, you could wind up with a dangerously high dosage of medicine, or even the wrong medicine altogether.

In 2006, the National Academies of Science's Institute of Medicine estimated that doctors’ sloppy handwriting was killing more than 7000 people per year, and preventable medication errors were harming around 1.5 million Americans annually. Many medical offices have since switched to electronic medical records and prescriptions, and some states have even required them to do so.

But that doesn’t tell us why doctors’ penmanship is so poor in the first place. One reason is because doctors have to write much more than we realize.

“In the medical field, if it’s not documented, it didn’t happen,” Celine Thum, medical director at ParaDocs Worldwide, told The Healthy.

If you’re the very first patient of the day, the record of your visit and any prescription slips you get might be perfectly legible. Ten hours and dozens of appointments later, however, your doctor’s hand muscles are probably pretty cramped.

The content they’re writing isn’t particularly easy to spell, either. If a doctor is jotting down glomerulonephritis, for example, they may not stop to make sure all those vowels are in the right places.

“We have so many technical terms that are impossible to write,” Thum said. “You sometimes scribble to cover the error.”

However, if a prescription looks indecipherable to you, it’s possible that your doctor is using shorthand that your pharmacist will immediately understand—like the abbreviation QD, from the Latin phrase for “one a day.”

If you’re confused about what the doctor has written on your prescription slip, you can always ask them to clarify aloud, and double-check that it matches what’s printed on your prescription bottle.

[h/t MSN]

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