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SHANNON MAY

6 Behind-the-Scenes Secrets of Supermarkets

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SHANNON MAY

Your local grocery store is a psychological minefield, where even the bananas are ripe with mystery.

1. SOUTHPAWS HAVE AN INVISIBLE ADVANTAGE

You’ve probably seen that stores keep go-to items—produce, meats, dairy—on the perimeter. But did you notice that most of them are set up to make your lap run counterclockwise? “Ninety percent of us are right-handed, so we buy more when it’s counterclockwise. It puts us closer to the shelf,” says Martin Lindstrom, author of Brandwashed: Tricks Companies Use to Manipulate Our Minds and Persuade Us to Buy. Places that do this see sales climb 7 percent. You’ll also often find the dairy section in the back left corner: Because dairy is likely on your list, stores make sure you take the longest route to get there. In fairness, it’s also a more convenient place to put a fridge.

2. EVERYTHING IN ITS PLACE

Psychologists weigh in on some store layouts. “They study buyers’ behavior and they come and reset the store based on perceived habits,” says Jake Sitler of Barry’s Country Food Market in Craley, Pennsylvania. It’s safe to say that nothing you see on a shelf is there by chance. The cookies on sale at the end of an aisle may look like a coincidental great deal, but they’re likely the result of product placement—a company paid for that real estate. It’s a smart spot: Besides the checkout counter, most impulse buys occur at the endcaps. More expensive items are usually placed at an adult’s eye level, while colorful cereals and treats are positioned lower—to catch the gaze of children.

3. WHAT YOU SEE IS WHAT YOU GET

When an employee says they’ll “check in the back” for an item, they’re just being polite. Most stores order goods to go directly from the truck to the shelf, skipping the back room entirely. “There’s an assumption we have so much stuff in our back room, and it is absolutely false,” says Dara Gocheski, a former Trader Joe’s employee.

4. THE EXPIRATION DATE ON THAT MEAT MAY BE MEANINGLESS

Matt Adams, who spent 28 years as a supermarket meat cutter, says his employer frequently used nail polish remover to wipe the sell-by date off outdated items. “You guys can’t do this,” he said. “What if some little old lady buys this?” It turns out you can. If meat was packaged under the watch of federal inspectors, supermarkets can’t change the date. But if the retailers butchered and packaged the meat themselves, they can change the label on a whim. In fact, 30 states don’t regulate the expiration dates for most items.

5. TIME GOES BY SO SLOWLY

Supermarkets rarely have windows or clocks. With no reference to the outside world, customers can easily lose track of how long they’ve been there. Grocery store overlords may use another trick to manipulate your sense of time: small floor tiles. The incessant click-clack of a shopping cart’s wheels can make customers think they’re racing around and encourages them to take a relaxed pace. And stores know that at a relaxed pace, customers buy more.

6. BANANAS ARE AN ART FORM

Bananas are so important to a supermarket’s bottom line that grocers know exactly what shade of banana you’re most likely to buy: Pantone color 12-0752, also known as “Buttercup.” To ensure the bananas on display are the closest to this shade, stores use a ripeness scale that ranges from one (all green) to seven (yellow with brown flecks). Some stores even use special lighting to make bananas look more appealing. “They’ll filter an ambient light in front of the box used to highlight the bananas so they become more yellow,” Lindstrom says. As for the water sprayed on the other produce? It makes veggies look fresh, but keeping them wet actually makes them rot faster. It also makes produce heavier—and therefore pricier.

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iStock // Ekaterina Minaeva
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Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
May 21, 2017
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iStock // Ekaterina Minaeva

Jacques Mattheij made a small, but awesome, mistake. He went on eBay one evening and bid on a bunch of bulk LEGO brick auctions, then went to sleep. Upon waking, he discovered that he was the high bidder on many, and was now the proud owner of two tons of LEGO bricks. (This is about 4400 pounds.) He wrote, "[L]esson 1: if you win almost all bids you are bidding too high."

Mattheij had noticed that bulk, unsorted bricks sell for something like €10/kilogram, whereas sets are roughly €40/kg and rare parts go for up to €100/kg. Much of the value of the bricks is in their sorting. If he could reduce the entropy of these bins of unsorted bricks, he could make a tidy profit. While many people do this work by hand, the problem is enormous—just the kind of challenge for a computer. Mattheij writes:

There are 38000+ shapes and there are 100+ possible shades of color (you can roughly tell how old someone is by asking them what lego colors they remember from their youth).

In the following months, Mattheij built a proof-of-concept sorting system using, of course, LEGO. He broke the problem down into a series of sub-problems (including "feeding LEGO reliably from a hopper is surprisingly hard," one of those facts of nature that will stymie even the best system design). After tinkering with the prototype at length, he expanded the system to a surprisingly complex system of conveyer belts (powered by a home treadmill), various pieces of cabinetry, and "copious quantities of crazy glue."

Here's a video showing the current system running at low speed:

The key part of the system was running the bricks past a camera paired with a computer running a neural net-based image classifier. That allows the computer (when sufficiently trained on brick images) to recognize bricks and thus categorize them by color, shape, or other parameters. Remember that as bricks pass by, they can be in any orientation, can be dirty, can even be stuck to other pieces. So having a flexible software system is key to recognizing—in a fraction of a second—what a given brick is, in order to sort it out. When a match is found, a jet of compressed air pops the piece off the conveyer belt and into a waiting bin.

After much experimentation, Mattheij rewrote the software (several times in fact) to accomplish a variety of basic tasks. At its core, the system takes images from a webcam and feeds them to a neural network to do the classification. Of course, the neural net needs to be "trained" by showing it lots of images, and telling it what those images represent. Mattheij's breakthrough was allowing the machine to effectively train itself, with guidance: Running pieces through allows the system to take its own photos, make a guess, and build on that guess. As long as Mattheij corrects the incorrect guesses, he ends up with a decent (and self-reinforcing) corpus of training data. As the machine continues running, it can rack up more training, allowing it to recognize a broad variety of pieces on the fly.

Here's another video, focusing on how the pieces move on conveyer belts (running at slow speed so puny humans can follow). You can also see the air jets in action:

In an email interview, Mattheij told Mental Floss that the system currently sorts LEGO bricks into more than 50 categories. It can also be run in a color-sorting mode to bin the parts across 12 color groups. (Thus at present you'd likely do a two-pass sort on the bricks: once for shape, then a separate pass for color.) He continues to refine the system, with a focus on making its recognition abilities faster. At some point down the line, he plans to make the software portion open source. You're on your own as far as building conveyer belts, bins, and so forth.

Check out Mattheij's writeup in two parts for more information. It starts with an overview of the story, followed up with a deep dive on the software. He's also tweeting about the project (among other things). And if you look around a bit, you'll find bulk LEGO brick auctions online—it's definitely a thing!

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Name the Author Based on the Character
May 23, 2017
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