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How Does a Plastic Bag Fix a Buggy Credit Card?

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Reader Amanda writes, “I was a cashier for a few years and when the register wouldn’t read a credit card, we would wrap the card in a plastic bag and run it through again and it would work. What makes the register read the card when it’s wrapped with a plastic bag?"

The black stripe on the back side of the credit card is made up of a bunch of tiny magnetic particles bound in plastic. The particles are arranged in magnetic and non-magnetic “zones” to encode the data—like your account number, expiration date, etc.—that the card reader on the register needs to process the transaction. When you swipe the card, the card reader reads the information by detecting the changes between the zones. For the transaction to work, the info needs to get from the card to the reader to the computer without any errors.

The strip is pretty delicate, and the data on it can be corrupted by exposing it to a strong magnet or scratching it. Damage can also occur gradually with use and carrying the card around in your wallet. Over time, some of the magnetic particles can get dragged out of position in a process called smearing. If enough magnetic bits move into a non-magnetic space to create a weak signal, the data gets corrupted and the card reader gets an error.

With just a little bit of magnetic material in them, the contaminated non-magnetic zones still have a much lower magnetic strength than the parts that are supposed to magnetized. Increasing the distance between the card reader and the corrupted zones is enough to get  the reader to read those weak parts as non-magnetized again. A plastic bag, usually at-hand at the cash register, makes a great spacer. Wrapped around the card, the bag basically mutes the corrupted parts of the magnetic stripe so the reader is presented with the data as its supposed to be.

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Big Questions
Is There Really Such Thing As 'Muscle Memory'?
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Is there really such a thing as 'muscle memory'? For example, in the sense of your fingers remembering where the keys of the keyboard are?

C Stuart Hardwick:

Yes and no. There is no literal memory in the muscles, but the thing people call “muscle memory” exists, though the name is a misnomer.

A better name might be “subconscious memory,” as the information is stored in the brain, but is most readily accessible—or only accessible—by non-conscious means.

What “non-conscious” refers to here is the brain’s enormous capacity to train up what might almost be called “subroutines,” that exist outside our conscious experience. I like the term for this that at least one researcher in the field uses: “zombie agency.”

Zombie agents are non-conscious, or sub-conscious (in the literal, not the Freudian sense) that can do essentially everything you can do except make value judgments. So, for example, you don’t consciously know how to control your muscles in order to walk —in all likelihood, you wouldn’t know where to begin—but your zombie agents do, and they’ll take you wherever you want to go, dodging curbs and puppies, and “waking you” when appropriate to decide which babies to stop and kiss.

Zombie agents can be rather startling things. When you suddenly become aware that you’ve driven halfway across town in the direction of the office instead of going to the shoe store Saturday morning, you have zombie agents to thank. You “wake” as if from slumber, and with the frightening realization that you’ve been flying down the highway at prodigious speed while your mind was on other things. You feel as if you’ve been asleep, and in a way you have—but a very funny kind of sleep in which it is only the uppermost layer of abstract reason that is disassociated from the rest of conscious experience. Your zombie agents have been driving to work, responding to traffic, adjusting the radio, noting the check engine light, all the things you think of as “you, driving the car,” except the big one: deciding where to go. That part was on automatic pilot (which is another good way to think of this).

This is at the advanced end of the spectrum. Typing your friend’s phone number using “muscle memory” is at the other, but it’s the same phenomenon.

We didn’t evolve to remember phone numbers, so we aren’t very good at it. In fact, we are so bad at it, we invent all sorts of mnemonic devices (memory aids) to help us [in] relating numbers to words or spacial memory, either of which are closer to the hunting and gathering we are evolved for. The illusion of “muscle memory” arises because we are supremely well adapted to manual manipulation and tool-making. We don’t need to invent a memory aid to help us remember what we do with our hands, we only have to practice.

So the conscious mind says “dial Tabby’s number,” and our fingers—or more correctly, the zombie agent which learned that task—do it. Similarly, after sufficient training, we can do the same thing with tasks like “play a major fifth,” "drive to work,” or “pull an Airbus A380 up for a go-around.”

It feels like muscle memory because the conscious mind—the part you experience as being you—is acting like a coach driver, steering the efforts of a team of zombie agents, all harnesses to collective action. But it isn’t muscle memory, it's just memory—though it may be stored (or at least some of it) in the deeper, motor cortex parts of the brain.

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

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Why Do We Toss Beads During Mardi Gras?

Every year, over 1 million people descend on New Orleans for Mardi Gras, an organized parade of debauchery and alcohol-induced torpor that may be the closest thing modern civilization has to the excesses of ancient Rome. Saturating the scene on Bourbon Street are plastic beads, handed or tossed to partygoers as a kind of currency. Some bare their breasts or offer booze in exchange for the tokens; others catch them in the air and wear the layers around their necks. Roughly 25 million pounds of beads are in circulation annually, making them as much a part of the Fat Tuesday celebration as sugary cocktails and King Cake.

Traditions and rituals can be hard to pin down, but Mardi Gras historians believe the idea of distributing trinkets started in the 1870s or 1880s, several hundred years after French settlers introduced the celebration to Louisiana in the 1600s. Party organizers—known locally as "krewes"—handed out baubles and other shiny objects to revelers to help commemorate the occasion. Some of them threw chocolate-covered almonds. They were joined by more mischievous attendees, who threw dirt or flour on people in an effort to stir up a little bit of trouble.

Why beads? Tiny tokens that represent wealth, health, and other prosperity have been a part of human history for centuries. In Egypt, tokens were handed out in the hopes they would guarantee a happy afterlife; the abacus, or bead-based system of accounting, used trinkets to perform calculations; pagan pre-winter rituals had people throwing grains into fields hoping to appease gods that would nourish their crops.

Humans, argues archaeologist Laurie Wilkie, display "bead lust," or a penchant for shiny objects. It's one possible reason why Mardi Gras attracts so many people with their arms in the air, elated to receive a gift of cheap, sweatshop-made plastic.

Photo of a well-dressed bulldog celebrating Mardi Gras in New Orleans.
Mario Tama, Getty Images

The early beads were made of glass before more efficient production methods overseas led to an influx of plastic beads in the 1960s. Unlike some of the more organic predecessors, these beads have come under criticism for being a source of health problems and pollution. Made from petroleum, they often harbor lead that seeps into the soil and rubs off on hands. (One estimate puts the lead deposit after a Mardi Gras celebration at 4000 pounds.) In 2017, New Orleans paid $7 million in clean-up costs to remove discarded beads from drain basins. This year, they've installed gutter guards to prevent the necklaces from getting into the system in the first place.

Environmental hazards aside, the beads of Mardi Gras have become as much a holiday staple as seasonal stockings or Thanksgiving turkeys. But the passion and desperate need for them is only temporary; last year, 46 tons of the beads were left in the gutters and drains. And no bacchanal should leave that much bad juju behind.

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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