Why Do We Get Shivers Up Our Spines?

iStock.com/martin-dm
iStock.com/martin-dm

Picture this: You're sitting on your couch in the dark alone, watching a scary movie. The killer is walking toward an unsuspecting victim, then suddenly jumps out at her. In that moment, the hairs on your body stand up, and you get a shiver down your spine. When you go for a walk on a crisp morning, the same thing happens. When the music swells during your favorite song, you get the shivers again, this time with the little goosebumps on your arms that appear when you get that sensation.

There's a good reason for shivers and goosebumps: they're your body's response to emotion or stress. We got this from our animal ancestors. When they were cold, the hair on their bodies would stand up—the movement of the arrector pili muscle would cause the skin to contract, raising each hair—to provide an extra layer of insulation. This response is also in play when animals feel threatened: their natural reaction is to try to look bigger than their attacker, so their skin and hair expand to play up that effect. The part of the brain called the hypothalamus is what controls this reaction.

So why do goosebumps—also known as cutis anserina or piloerection—appear, aside from the functional purpose of looking larger or creating insulation? It's because our emotions are also connected with the hypothalamus, so sometimes goosebumps are just our body reacting to our brain's signals of intense emotion.

When we feel things like love, fear, or sadness, the hypothalamus sends a signal to our bodies that produces adrenaline in our blood. The signal triggers the arrector pili muscles to contract, and then we have goosebumps caused by emotion. The sudden adrenaline rush may also cause sweaty palms, tears, increased blood pressure, or shivers.

When we listen to music and get shivers, it is a mixture of subjective emotions toward the music and physiological arousal. If we hear a song we get excited about, or a song that makes us sad, the hypothalamus reacts to the sudden change in emotion and we physically feel the shiver along our spine.

This article was republished in 2019.

What Happens During a Jeopardy! Commercial Break?

Jeopardy! host Alex Trebek chats with the show's contestants.
Jeopardy! host Alex Trebek chats with the show's contestants.
Getty Images Entertainment

Jennifer Quail:

Typical Break One: First, if there are "pickups" (re-recordings where Alex misspoke or coughed or stuttered, or Johnny mispronounced someone’s name or hometown) to record, they do those. A stagehand brings water bottles for the contestants. The production team who wrangles contestants comes over and gives their pep talk, makes any corrections, like if someone is consistently buzzing early; and keeps you quiet if there are pickups. Alex gets the cards with the "fun facts" (there are about three, one highlighted, but which one he goes for is ultimately up to Alex alone) and when the crew is ready, they come back from commercial to Alex’s chat with the contestants.

Typical Break Two: If there are any pickups from the second half of the Jeopardy! round they do those, the water gets distributed, the production team reminds the contestants how Double Jeopardy! works and that there’s still lots of money out there to win, and Alex comes over to take a picture with the two challengers (the champion will have had their picture taken during their first match.) Then we come back to Double Jeopardy!.

Typical Third Break: This is the big one. There are pickups, water, etc. and they activate the section of the screen where you write your wager. One of the team members brings you a half-sheet of paper ... and you work out what you want to bet. One of your "wranglers" checks it, as does another production team member, to make sure it’s legible and when you’re sure that’s what you want, you lock it in. At that point you can’t change it. They take away the scratch paper and the part of the board where you write your answer is unlocked. Someone will tell you to write either WHO or WHAT in the upper left corner, so you do know at least whether it’s a person or thing. They make sure the "backup card" (a piece of card stock sitting on your podium) is turned to the correct who or what side, just in case your touchscreen fails. If everything’s ready, then as soon as the crew says, they come back and Final Jeopardy! starts.

There are breaks you don’t [even know about, too]. If there is a question about someone’s final answer, they will actually stop tape while the research team checks. Sometimes if something goes really off, like Alex completely misreads a category during the start of a round, they’ll stop and pick it up immediately. Those [are breaks] you’ll never notice because they’ll be completely edited out.

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

Why Is There a Leap Day?

Bychykhin_Olexandr/iStock via Getty Images
Bychykhin_Olexandr/iStock via Getty Images

At some point in elementary school, your science teacher probably explained to you that there are 365 days in a year because that’s how long it takes for Earth to complete one full rotation around the sun. What they might not have specified, however, is that it’s not exactly 365 days—it’s actually closer to 365.2421 days.

So, if we want our calendar year to begin right when Earth begins a new rotation around the sun, we have to account for (roughly) an extra quarter of a day each year, or one day every four years. History.com reports that the Egyptians had already been doing this for a while before Europe finally caught on in 46 B.C.E., when Roman dictator Julius Caesar and astronomer Sosigenes put their heads together to come up with what we now call the Julian calendar, which includes 12 months, 365 days, and an additional “leap day” every four years on February 29.

But rounding 0.2421 up to 0.25 each year created an issue, because it didn’t quite add up to a full day every four years—and that tiny discrepancy meant that after 128 years, the calendar year ended up starting a day before Earth had completed its rotation around the sun. By the 14th century, the calendar year was starting a whopping 10 days before Earth finished its orbit.

In 1582, Pope Gregory XIII sought to correct the error by suggesting that we simply skip a leap day every so often. His Gregorian calendar, which we still use today, mandates that we omit the leap day during years evenly divisible by 100 but not by 400. For instance, the year 2000 included a leap day because it’s divisible by 100 and 400; the year 2100, on the other hand, will not include a leap day, since it’s evenly divisible by 100, but not by 400.

Gregory XIII’s correction to Caesar’s overcorrection is itself a bit of an under-correction, so we’ll probably need to reevaluate our leap day protocol again in about 10,000 years.

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