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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What Does 'State of Emergency' Really Mean?

Firefighters battle a state of emergency.
Firefighters battle a state of emergency.
Phonix_a/iStock via Getty Images

Local and state officials across the U.S. are declaring states of emergency in their efforts to manage the coronavirus pandemic. Some entire countries, including Italy and Japan, have also declared a state of emergency. But what does this phrase really entail?

Local and State Response

The answer varies a bit from state to state. Essentially, declaring a state of emergency gives the governor and his or her emergency management team a bit of extra latitude to deal with a situation quickly and with maximum coordination. Most of these powers are straightforward: The governor can close state offices, deploy the National Guard and other emergency responders, and make evacuation recommendations.

Other powers are specific to a certain situation. For example, in a blizzard, a governor can impose travel restrictions to clear roads for snowplows and other emergency vehicles.

Calling in the Feds

If a disaster is so severe that state and local governments don’t have the cash or the logistical ability to adequately respond, the governor can ask for a declaration of a federal emergency. In this case, the Federal Emergency Management Agency (FEMA) does a preliminary damage assessment to help determine whether the governor should petition the president for a federal emergency declaration.

When the declaration from the president comes through, state and local governments can get funding and logistical help from the feds. What makes a crisis a federal emergency? The list is pretty broad, but FEMA shares some criteria here.

Why Does Hand Sanitizer Have an Expiration Date?

Hand sanitizer does expire. Here's why.
Hand sanitizer does expire. Here's why.
galitskaya/iStock via Getty Images

The coronavirus pandemic has turned hand sanitizer from something that was once idly tossed into cars and drawers into a bit of a national obsession. Shortages persist, and people are trying to make their own, often to little avail. (DIY sanitizer may not be sterile or contain the proper concentration of ingredients.)

If you do manage to get your hands on a bottle of Purell or other name-brand sanitizer, you may notice it typically has an expiration date. Can it really go “bad” and be rendered less effective?

The short answer: yes. Hand sanitizer is typically made up of at least 60 percent alcohol, which is enough to provide germicidal benefit when applied to your hands. According to Insider, that crucial percentage of alcohol can be affected over time once it begins to evaporate after the bottle has been opened. As the volume is reduced, so is the effectiveness of the solution.

Though there’s no hard rule on how long it takes a bottle of sanitizer to lose alcohol content, manufacturers usually set the expiration date three years from the time of production. (Because the product is regulated by the Food and Drug Administration, it has to have an expiration date.)

Let's assume you’ve found a bottle of old and forgotten sanitizer in your house somewhere. It expired in 2018. Should you still use it? It’s not ideal, but if you have no other options, even a reduced amount of alcohol will still have some germ-fighting effectiveness. If it’s never been opened, you’re in better shape, as more of the alcohol will have remained.

Remember that sanitizer of any potency is best left to times when soap and water isn’t available. Consider it a bridge until you’re able to get your hands under a faucet. There’s no substitution for a good scrub.

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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