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W.W. Norton / Chris Hardy Photography

Q&A: Mary Roach, Author of Gulp

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W.W. Norton / Chris Hardy Photography

Mary Roach's book, Gulp: Adventures on the Alimentary Canal, is available in paperback now. We talked to the author about making gross topics palatable to readers, putting yourself out there for science, and the parts of the alimentary canal that just aren't that interesting.

Your books are all about topics people probably didn't realize they wanted to know about until they start reading. How do you come up with your ideas? What drew you to the alimentary canal?

Well, I like writing books, and the thing that trips me up is that I’m not very—it's not like I have a list of ideas to work through as the years unfold. I do one book and then I go, “Oh God, I don’t have any more ideas, what am I going to do?” I kind of come at it inside out. I’ll have two or three chunks of material that didn’t get put into a book or a story, and then I’ll go, “Oh, if I took all two or three of these, what would be the umbrella over all of those that might be…” I’ll have some specifics and then put a book around them, which I don’t recommend to anybody. It’s kind of a stupid way to come up with books.

In this case, I had done this story on flatulence—it was like 1989 or something—and I had all this great material. It was one of those [stories] like, “We just want to tell readers how not to be flatulent.” I’m like, “First of all, people like to fart. [Laughs.] So I don’t want to tell people how not to.” It was a service kind of piece, so I couldn’t really use the Mylar pantaloons and I couldn’t use the fabulous history of flatulence research, or any other wonderful moments at Beano, where I had gone to report that story. And I had a few other miscellaneous, digestive tract-related, fabulous chunks of material. And at a certain point I went, “Oh, duh! The alimentary canal. It’s like a Mary Roach travel book. You just start at one end and go out the other.”

I don’t know why it took me so long to think of the idea. I would go to book talks and people would go, “You should do a book about sh*t,” and I’d go, “Hmm … I see where you’re coming from, but I think that’s a little specific and embarrassing.” At a certain point, I realized that I could incorporate some elements of that, but the mouth is also an interesting place too, and the stomach. There were just so many interesting places you could go.

Because I’m doing it, I don’t really feel any compulsion to be thorough. Like, the liver? Boring. You’re out of here. Some people are like, “Did you know you forgot the liver?” I’m like, “Yeah.” I couldn’t find an interesting liver chapter setting. What would make the liver fun and exciting? Nothing makes the liver fun and exciting. The small intestine got shafted too. It’s in there—I explain it here and there—but it didn’t get its own chapter because you know what? It’s not that fun. It’s the boring relative that nobody really wants to sit next to.

How do you approach your research? You go a lot of places, you talk to a lot of people, you cite a lot of papers; I can’t even wrap my head around organizing it into a book.

I approach it this way: For every stop along the alimentary canal, I wanted to have a scene, a setting, person, dialogue, something going on, whether it was historical or current, somewhere I would travel. So I spent a lot of time contacting strangers, like the fecal transplant guy, and going, “Alright, this is going to sound weird, but can I come out and be there when you put the stuff in the blender and when you do the actual transplant? Is that OK?” And he’s like, “Yeah, sure. Whatever turns you on.”

So a lot of it’s contacting people and saying, “What’s going to be happening in your lab in the next few years?” I’m very straightforward with them. I say, “I need a setting and scene and things going on, and you’re going to be a character in this chapter, so let me know: What have you got cooking?”

I spend a lot of time early on doing that, trying to find that kind of narrative structure for each chapter, which comes down to really whose lab we’re going to visit. Or not always a lab—sometimes it’s Avenal State Prison. I called up the public affairs guy at the California Department of Corrections and Rehabilitation and said, “You know what, I’m doing this book; I’ve got this rectum chapter and I know you guys have some issues with rectal smuggling…” I thought the guy would hang up, but he went, “Oh yeah, we have some real problems with cellphone hooping. Sure, you can come down to Avenal. We’ll set up some interviews.” [Laughs.] I’m like, “Really? Great! I’m there.”

It is definitely surprising that they gave you that kind of access.

I know. I really didn’t expect that. I thought, if anything, they’d say, “Oh, you can talk to one of the guards who does the cavity searches.” But they were like, “Here’s a guy who’s really good at this. Talk to him about his rectum.” I’m like, “OK. That sounds great.” So it’s really a lot of sending out emails to people you’ve never met and hoping that they’ll look kindly upon you and let you eat up their time.

Do you find that most of the time people are very excited to talk about their research that they’re doing, or are there some people who are just not interested?

Usually, people are delighted to have the opportunity to talk to somebody who’s interested. Every now and then I’ll get somebody who’s a little bit uncomfortable with how they might be portrayed, like whether I’ll take it seriously enough. But that’s very unusual. Oftentimes it’s people who have read my books, and amazingly enough, they agree to be in them—like, “Yeah, I’ve read such-and-such. Sure, you can come down.” And they’re even more helpful if they’re familiar with the books, which I really didn’t see coming. Early on in my career, I thought that with each successive book that it would get harder and harder, because people would say, “I’m not so sure.”

It’s a leap of faith. They have to trust me, and there’s no reason to. They’ve got to trust that [I'm] going to get something right, that the way that they’re portrayed isn't going to affect their ability to get funding in the future. That was an issue with some of the NASA contractors [she talked to for her last book, Packing for Mars]. They were happy to talk, but they were concerned that they might not get work from NASA in the future—that it would affect their ability to work with NASA, because they didn’t really know how the work would be portrayed. It’s always very generous of people to agree.

Most people are really good sports. They appreciate it. I showed the cadaver chapter in Packing for Mars to the researcher; that was one thing he wanted. He initially read it, and he said, “Well, the first time I read it, I thought, ‘I’d better get my C.V. together.’” And then he said, “And then I read it another time with my researcher goggles on, and I was like, ‘You know, this is fine. There’s one line I’d really like you to take out, but that’s it.’” So yeah, people are good sports.

At this point, you’ve been doing this for a while, so do you have a sense of what will make for a good place to visit? Has there ever been a time where you’ve gone to see something and it just has been the most boring thing ever?

Oh, sure. Often, I will hear about something and go, “Oh, this sounds like it’d be really cool! I’m going to go there!” And then a couple of times—it’s happened more with magazine features where I’ve showed up and it’s just really dull. A lot of the time it’s my fault for being over-optimistic. There was a story once about the ergonomics of airplane seats, and there’s a lab where they have people test airplane seats, and I thought, “Wow, that sounds really interesting and bizarre; I’ll go be a subject.” Well, it just means you’re sitting on your ass in a plane seat for eight hours. And I did it anyway, but it was kind of a challenge to make that interesting.

So that will happen every now and then; what I’ll do is just end up having very little material to work with. There’s always five or ten minutes somewhere in the course of those two days that make a scene that’s interesting. It’s a salvage job, sometimes. It’s rare that I will completely drop the chapter, although that has happened—I just think, “You know, this doesn’t make the cut.”

When you’re dealing with the stuff you touch on in Gulp—which is definitely gross—do you ever worry about alienating readers? How do you make it accessible?

I rely on my editor. If I’ve really gone too far—she has a more delicate sensibility than me, so I don’t trouble myself with it. Because I’m not a good judge of it; I’ll throw anything in. But if she trips over it, then I really have to look at it and say, “She’s probably right. This is probably a little too much.” So she’s kind of my eyes and ears of more civilized society. I just put it in there and she surprises me with how rarely that actually happens.

Was there anything in Gulp that she suggested that you cut?

You know, it’s funny—when I turned in the manuscript, I thought all the problems would be with the second part, the below-the-waist half of the book. She didn’t have a single problem with that. She wanted some different things up front, in the first half. Editors are more concerned with the first chapters of a book; that’s what everyone reads first in the bookstore or in the online sample. I anticipated some hesitation with the flatulence chapters, for example, or hooping, but no, nothing. She didn’t take anything out. [And usually,] it’s more often a line where she doesn’t get the humor—she doesn’t think it works, and she’ll flag it. It’s not usually “This is too disgusting.”

When you buy my books, you kind of know what you’re in for. It’s kind of self-selecting. If you have a delicate sensibility and you’re easily grossed out, you probably will never read one of my books.

When the book was released, you took it out on tour. What kinds of things were people asking you about?

Well, you get a fair amount of personal medical questions that you’re not qualified to answer. But the rest were better than I had anticipated. I thought we were going to get—particularly, with call-in radio—a lot of, like, “I have been diagnosed with mucoid plaque and I was wondering what the latest treatment is. What do you recommend?” That kind of thing. I’m not an M.D. So I did get a little of that, but not as much as I’d feared. I thought I’d get a lot of people asking about gluten and lactose intolerance and those kind of conditions that have become so talked-about in our culture, but people kind of got that it wasn’t a health book, that it wasn’t a personal health book. They’d get that, so there weren’t as many as I thought there would be.

A lot of people just generally approached it in the spirit in which it was written, and they had wonderful questions. One guy talked about how hot foods—you know, you burn out the pain receptors [in your mouth] and you develop this tolerance from hot peppers. He said, “Why don’t you develop a tolerance on the other end?” And I’m like, “That is the best question ever.” [Laughs.] People come up with stuff like that, which I always enjoy, though I don’t always have an answer.

Does it ever make you want to go back and add an addendum?

Yes, absolutely. And also people raise their hands and go, “Oh, my uncle was the gastroenterologist for Fidel Castro.” I mean, people come up with these amazing stories, and I'm like, “Where were you two years ago?” What can you do? 

I was particularly interested in the section about how pet food is made. I have a very finicky cat, and I had no idea that so much went into making food taste good for him. Why did you decide to include how pet food is made, even though we're not eating it?

I thought it would be interesting to do a human taste panel. I did have that for the wine chapter, but that was more the nose, and I thought the nose was the more interesting element there. I wanted to do maybe a texture panel, but somehow this is one of those cases where the reality of it would seem to be less promising than how I thought it would be. At some point, somebody told me about pet food taste panels, and I was like, “Really?” Because who would guess that, in fact, there are animal taste panels? It makes sense that there are, and [the testers are] occasionally human beings. That was such a surprise, and it just seemed much more entertaining and fun. I was on a taste panel at NASA for Packing for Mars, and that’s an example of where I was a taster for some breakfast item, and it was so boring. The person I was interviewing—well, it didn’t sing. I left it out of the book. So I had a sense that this taste panel thing threatened to be dull, even though it seems like it should be kind of fun. So the pet food was just a way to make it a little fresher and more surprising.

So I wanted to talk a little bit about your footnotes. In a lot of books, I’ll skip them because they’re kind of boring. But your footnotes are always very funny. Sometimes they deal with what you're talking about, sometimes they don't, and sometimes they're just a joke you're making. Is that stuff that was going to go in the text but got cut, or are you writing those and then putting them in as you go along?

It’s material that doesn’t really fit the narrative, but I can’t bear to leave out. So it’s just me being indulgent. If I’ll have something that I have in a folder and I can’t find a way to fit it in that isn’t distracting or annoying for the reader, I’ll put it in a footnote. Some chapters have a lot of them; some don’t. Some books have a lot, some more of them. I’m tending on doing fewer of them because they don’t work so well with e-Books. They take people off the page to another part—a dedicated page—and then they have to go back, is how it’s been working, and people don’t like it. So I’m doing fewer of them with the next book.

It also just goes book-by-book. Like, Bonk has three times as many as Stiff, or Spook. Gulp has quite a few. Packing for Mars has quite a few. It kind of depends on the material. Sometimes there’s a bunch of footnote-worthy stuff and other times there’s not.

Did you have a favorite footnote from Gulp?

I did enjoy the International Hairball Awareness Day footnote because, in fact, the book came out right around that time, and people did write to me saying, “Hey, I’m reading the National Hairball Awareness Day footnote on National Hairball Awareness Day!” Eight or nine people wrote to me, which was very fun. So that one was particularly fabulous.

Also, there was one that maybe 30 percent of people got, and this was something my editor wanted to take out, and I left it in. Anyway, there was a flatulence patient whose name was Flatus Backwards. And I wrote, “Get it?” backwards, as the footnote. And nobody got it. People were like, “Excuse me, there’s some weird typographical problem with one of your footnotes that you seemed to have missed.” Like, nope, you missed it. Go back and reread it. My editor was like, “I showed this to my assistant and the publicist and we didn’t get it.” And then my agent’s like, “No, leave it in.” [Laughs.] That one was entertaining.

Did writing Gulp change the way you think about food and eating? Are you into Fletcherizing now?

[Laughs.] No, I’m definitely not into it. Fletcherizing is gross. I tried it once. I tried to go until it’s all liquid, and it just creeps you out to be focusing so much on your chewing.

And at a certain point, don’t you have a reflex where your mouth wants you to swallow?

Yeah, in fact that’s what Fletcher wanted you to go towards. He wanted you to involuntarily swallow [because] you just have to swallow it.

Mine seems to happen way before 700 chews.

Yeah, I think it was a particularly tough shallot he was chewing. I don’t know where he got his shallots, but that was a lot of chews.

Because of the nose chapter, I use my nose more, particularly with any kind of wine or gin or anything with a lot of those volatile vapors coming off of it. It’s very cool that you smell on the exhale as well as the inhale—that whenever you exhale, you’re smelling. It’s not just something you do on the inhale. I love when I come upon those very basic things that you go through your life not knowing. So, I make use of that more. But other than that, I didn’t change my diet or anything.

You talked to so many people for Gulp. Who was your favorite?

I really enjoyed Erika Silletti, the beautiful Italian saliva expert, partly because she was beautiful and Italian, and you don’t really think of a saliva expert as being that person, for some reason. She just had this passion for this topic—and same with [chewing scientist Andries van der Bilt]. They had these elements of the human body that people completely take for granted or dismiss as gross; they have lovely commitment and passion for it and they were just really lovely, fun, funny people. They were terrific.

And I loved the hooper. OK, he was a murderer. [Laughs.] But that was a long time ago, and he was a kid then. It’s very strange to say you really enjoyed the company of a murderer, but he was so good-natured about sitting down with a stranger and talking about what it’s like to hold large objects in your rectum for long periods of time. He was delightful, in his way.

You obviously feature a lot of historical figures, too. If you could sit down and have dinner with one of them, who would it be? And what would you be eating?

Just for the entertainment value, it would have to be Horace Fletcher. Somebody described [it]. I think it was William Forbes, in his journals. He went for "a meal with Horace Fletcher, well-chewed." I think it would be very entertaining. It would have to be something that requires a lot of chewing, because I would like to witness this strange phenomenon. There’s not film footage, that I’m aware of, of people Fletcherizing. We wouldn’t be having soup.

In the process of writing your books, you sometimes put yourself out there and become a subject of research yourself: In Gulp, you got a colonoscopy. What’s the most bizarre thing you’ve done in the process of researching a story? Is there anything you wouldn’t repeat?

Well, I wouldn’t repeat the ultrasound sex experience [from Bonk], just because I felt so bad for my husband. The burden of performance was on him. And this was not, as people say, an MRI, but it was an ultrasound, which was even more awkward because the guy is right there holding the wand to my belly. Yeah, that was extremely awkward. At the same time, as it was going on, I was taking notes. I knew that this was going to be so fun to write up. Having written it up, I see no reason to repeat that kind of experience.

That seems like, hands down, the most bizarre thing you’ve done for a story.

Yeah, it’s one of those things where I signed up immediately without really thinking it through. I knew that I needed to do it for the book, because I couldn’t talk to Virginia Johnson’s subjects—they’re all anonymous. And if you put an ad in the paper, you get people saying, “Oh yeah, I was one of her subjects, I’ll tell you what it was like.” And she was alive then [Ed. note: Johnson died in 2013], and she didn’t want to participate, so I just thought that in order to describe this experience—the experience of being a study subject in a sexual physiology study—it’s a very unusual thing to do. So doing it myself was kind of the only way to get at it.

What’s the most surprising thing you learned from writing Gulp?

There were lots of little surprises along the way, like the thing about smelling when you exhale. And that’s, incidentally, why people can smell their own breath—because every time you exhale, you’re smelling it. I was thinking it’s sort of because you exhale, and then that breath is in front of your nose, and you inhale it. But it’s because every time you exhale, you’re smelling it.

I guess, also, the reluctance or the slowness with which fecal transplants have caught on, because they’re so effective, so cheap, so safe. That’s a rare thing in medicine. And the fact that it’s, all along, been kind of hobbled by people's discomfort with it. It’s also because there’s no corporate entity pushing it through, paying for the trials. That’s also why. But I guess that was surprising.

What do you hope people take away from reading the book?

A little bit of respect for their innards, I guess, or just a little more awareness of what’s going on in there, and that it’s pretty cool, fascinating. Don’t take your guts for granted.

I mean, just reading about Elvis’s megacolon made me think, “Thank god I have a regular colon!”

Yeah, people don’t appreciate their intestines until something goes wrong. But I always hope that people gain a little appreciation for their guts.

When you’re not writing and researching, what kind of things are you reading? Have you read anything really good in the past eight months that you would really recommend to people?

I am right now reading a book by this author I just discovered named Dave Madden, who wrote this book called The Authentic Animal, which is about taxidermy. He’s such a gifted creative nonfiction author. He’s very young. He’s not very well-known, and he just blows me away. He’s so good. So I’m reading that, and I’m also reading a novel by Rabih Alameddine called An Unnecessary Woman, which is also really, really good. Over the past year or so, the other book I really loved was Jon Mooallem, another creative nonfiction writer who’s just staggeringly good. He wrote a book called Wild Ones.

Want to learn more about Mary and Gulp? Click here.

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iStock // Ekaterina Minaeva
Man Buys Two Metric Tons of LEGO Bricks; Sorts Them Via Machine Learning
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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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Why Your iPhone Doesn't Always Show You the 'Decline Call' Button
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When you get an incoming call to your iPhone, the options that light up your screen aren't always the same. Sometimes you have the option to decline a call, and sometimes you only see a slider that allows you to answer, without an option to send the caller straight to voicemail. Why the difference?

A while back, Business Insider tracked down the answer to this conundrum of modern communication, and the answer turns out to be fairly simple.

If you get a call while your phone is locked, you’ll see the "slide to answer" button. In order to decline the call, you have to double-tap the power button on the top of the phone.

If your phone is unlocked, however, the screen that appears during an incoming call is different. You’ll see the two buttons, "accept" or "decline."

Either way, you get the options to set a reminder to call that person back or to immediately send them a text message. ("Dad, stop calling me at work, it’s 9 a.m.!")

[h/t Business Insider]