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Why Do We Bite Our Nails?

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It can happen anywhere. Maybe you're waiting in the lobby of your doctor's office or studying at home for a big test—and then, without you even registering it, your fingertips are in your mouth and your teeth are gnawing away.

Even the people who do it tend to see nail biting as a nasty habit, but that doesn't make it any less prevalent. Twenty to 30 percent of people admit to biting their nails on a regular basis. Though reasons for the behavior vary, research has shown that most people do it because they need a psychological crutch, and not because they like having dirty, ragged fingernails.

According to Kieron O'Connor, a researcher at the University Institute of Mental Health at Montreal, there’s no one mood associated with nail biting. “People think you only bite when you’re stressed, but it’s not so simple,” O'Connor tells Mental Floss. “People will also bite when they’re bored and alone.” Nail biting feels good (in moderation at least), so when some people have nothing to do, or want to avoid the task in front of them, they bring their nails to their mouth out of habit. This same thing happens when nail biters feel overwhelmed by a stressful situation, or when they’re ruminating over some past behavior they feel embarrassed about. In all cases, nail biting is used as a mood regulator: a tool that distracts them or provides temporary relief or stimulation whenever an unwanted feeling comes up.

A study co-authored by O’Connor found that nail biting is more common in perfectionists. After speaking with 48 subjects, half with habit disorders like nail biting and half without, they found that the nail biters tended to be organizational perfectionists, or people who tend to over-plan, work too much, and become restless when they don’t have enough to do. “When people are perfectionists, they get bored and frustrated very easily and hold themselves to higher standards,” O’Connor says. “They plan too much, and when they can’t do all of it they have a sense of failure.”

So what is it about nail biting specifically that makes some people turn to the behavior when they’re feeling less than fantastic? Like many of our worst habits, nail biting is an evolutionary adaptation kicked into overdrive. Even before we had access to aisles worth of beauty products, humans practiced self-grooming, which includes getting rid of the occasional hangnails. But even nail biters with short, clean nails will engage in the behavior: They use it as a way to get the mental reward our brains associate with grooming without any of the cosmetic benefits.

Nail biting manifests itself at different levels of intensity. At one extreme there’s onychophagia, a condition where compulsive nail biting requires medical attention. Like skin picking and hair pulling, nail biting can be a symptom of a body-focused habit disorder. When it gets to the point that someone is harming themselves by chewing their nails so often, they usually require a mental health professional to help them curtail the behavior.

But for far more people, nail biting is just an annoying habit that’s hard for them to quit—no matter how much the squeamish people around them wish they would.

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Why Are Mugshots Made Public Before a Suspect is Convicted by the Court?
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Jennifer Ellis:

Several reasons.

1. Mugshots can help find people when they have absconded, or warn people when someone is out and dangerous. So there is a good reason to share some mugshots.

2. Our legal system requires openness as per the federal constitution, and I imagine most if not all state constitutions. As such, this sort of information is not considered private and can be shared. Any effort to keep mugshots private would result in lawsuits by the press and lay people. This would be under the First and Sixth Amendments as well as the various Freedom of Information Acts. However, in 2016 a federal court ruled [PDF] that federal mugshots are no longer routinely available under the federal FOIA.

This is partially in recognition of the damage that mugshots can do online. In its opinion, the court noted that “[a] disclosed booking photo casts a long, damaging shadow over the depicted individual.” The court specifically mentions websites that put mugshots online, in its analysis. “In fact, mugshot websites collect and display booking photos from decades-old arrests: BustedMugshots and JustMugshots, to name a couple.” Some states have passed or are looking to pass laws to prevent release of mugshots prior to conviction. New Jersey is one example.

a) As the federal court recognizes, and as we all know, the reality is that if your picture in a mugshot is out there, regardless of whether you were convicted, it can have an unfortunate impact on your life. In the old days, this wasn’t too much of a problem because it really wasn’t easy to find mugshots. Now, with companies allegedly seeking to extort people into paying to get their images off the web, it has become a serious problem. Those companies may get in trouble if it can be proved that they are working in concert, getting paid to take the picture off one site and then putting it on another. But that is rare. In most cases, the picture is just public data to which there is no right of privacy under the law.

b) The underlying purpose of publicity is to avoid the government charging people and abusing the authority to do so. It was believed that the publicity would help protect people. And it does when you have a country that likes to hide what it is up to. But, it also can cause harm in a modern society like ours, where such things end up on the web and can cause permanent damage. Unfortunately, it is a bit of a catch-22. We have the right to know issues and free speech rights smack up against privacy rights and serious damage of reputation for people who have not been convicted of a crime. The law will no doubt continue to shake out over the next few years as it struggles to catch up with the technology.

This post originally appeared on Quora. Click here to view.

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What Happens When You Flush an Airplane Toilet?
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For millions of people, summer means an opportunity to hop on a plane and experience new and exciting sights, cultures, and food. It also means getting packed into a giant commercial aircraft and then wondering if you can make it to your next layover without submitting to the anxiety of using the onboard bathroom.

Roughly the size of an apartment pantry, these narrow facilities barely accommodate your outstretched knees; turbulence can make expelling waste a harrowing nightmare. Once you’ve successfully managed to complete the task and flush, what happens next?

Unlike our home toilets, planes can’t rely on water tanks to create passive suction to draw waste from the bowl. In addition to the expense of hauling hundreds of gallons of water, it’s impractical to leave standing water in an environment that shakes its contents like a snow globe. Originally, planes used an electronic pump system that moved waste along with a deodorizing liquid called Anotec. That method worked, but carrying the Anotec was undesirable for the same reasons as storing water: It raised fuel costs and added weight to the aircraft that could have been allocated for passengers. (Not surprisingly, airlines prefer to transport paying customers over blobs of poop.)

Beginning in the 1980s, planes used a pneumatic vacuum to suck liquids and solids down and away from the fixture. Once you hit the flush button, a valve at the bottom of the toilet opens, allowing the vacuum to siphon the contents out. (A nonstick coating similar to Teflon reduces the odds of any residue.) It travels to a storage tank near the back of the plane at high speeds, ready for ground crews to drain it once the airplane lands. The tank is then flushed out using a disinfectant.

If you’re also curious about timing your bathroom visit to avoid people waiting in line while you void, flight attendants say the best time to go is right after the captain turns off the seat belt sign and before drink service begins.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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