Daniel Engber Dissects the Ubiquitous Laboratory Mouse

Daniel Engber Courtesy of Daniel Engber

When Slate senior editor Daniel Engber took a month off from his usual duties to research a multi-part series on laboratory mice, he had a thesis—that although the ubiquity of mice as model organisms has clear advantages, it is in some ways damaging to biomedicine. What he needed was stories and characters to hang his argument on. Tracking down and sifting through numerous compelling narratives proved to be the most challenging—and also the most fun—aspect of reporting his series. Here, Engber discusses how he found his stories, how he overcame initial reservations about the topic, and how he put the pieces together. He also reveals his “invisible ink” method of battling writer’s block. The three-part series “The Mouse Trap” (1 | 2 | 3) appeared in Slate on November 16-18, 2011.

Here, Engber tells TON co-founder Siri Carpenter the story behind the story. (This interview has been edited for length and clarity.)


How did you get the idea for this story?

This one actually comes from the last one of these “Fresca” projects that Slate does [to encourage staffers to pursue long-form projects]. I did my first Fresca project in ’09, on animal welfare in the lab. One of the things I came across was the fact that rats and mice were exempted from the protections provided by the Laboratory Animal Welfare Act of 1966, which led to their becoming extremely popular animal models in biomedical research. I originally had a section of that 2009 Fresca project that was about what it means for the scientific community that we are using rats and mice so much. But the rest of that series was raising questions about animal welfare, and this big question about epistemology would have been kind of out of left field. So we cut that whole piece, which was maybe a 2,500-word section.

Then last year, I was thinking about a new Fresca project to do, and I thought maybe I could come back to this piece that seemed so fascinating to me, so I pitched it. Slate editor David Plotz agreed to do it so long as I was able to find some kind of narrative elements to include, because it was this abstract idea: that everyone’s using rats and mice, and particularly mice over the last 20 years, and that there are both advantages and disadvantages to having this monoculture of knowledge production in biomedicine. I didn’t have the skeleton of the story that I would then graft the idea onto—I just had the argument and no story. So I got a provisional “yes” on doing the project, contingent on my finding something to say.

This is one of those stories where a major set of issues in science seems, in retrospect, to have been hiding in plain sight. Why do you think this subject hasn’t gotten much journalistic attention before?

I think partly it goes back to one of the reasons why scientists are using mice to begin with, which is that they’re not very charismatic. This is a topic that people tend to drift away from because mice and rats tend to make people a little uncomfortable. Even in describing the project to people while I was working on it, people seemed instantly bored as soon as I started talking about mice.

The second thing is that this issue, to the extent that it can be resolved, would be resolved by the granting agencies. There’s nothing that a general Slate reader can do. It worried me throughout, and I tried to emphasize the analogy to monoculture in agriculture—which is directly related to the issue of mouse models—because I think that’s something that resonates more directly with people. Putting the story within that bigger context of the dangers of standardization and globalization, and of how increasing efficiency comes with hidden costs, my idea was that I could tie it in with bigger ideas that might be more exciting for people or affect their world view more broadly. It wasn’t just a story about science funding, but it could be a story about the hidden implications for American society.

What were your first steps in starting to report the story? What were your initial questions, and how did you start out your research?

I had two lines. As I said, I kind of had my thesis in place at the outset, which I think is dangerous for journalists, and unusual—but it came out of reporting from 2009. So having that thesis in mind, I set out to find people who were experts in science funding and biomedicine, like [Nobel Prize-winning former Director of the National Institutes of Health and current Director of the National Cancer Institute] Harold Varmus.

But the more important thing was to figure out the specific stories I was going to tell, because the thesis was so broad and hard to get a handle on. I had heard an interview with [author and journalist] Michael Lewis—I don’t remember what the venue was—and he was talking about his process, and he talked about the “casting calls” he does at the beginning of a project. It’s not like it’s a big secret; everybody knows you have to do something like a casting call when you’re beginning a new project. But I had never heard that phrase before in the journalism context, and it was really useful. It helped me realize that I needed to just get a whole bunch of leads and then do a casting call and find which of these stories and characters were the best.

How did you do that?

I reached out to people I knew who are biomedical researchers and told them I was looking for these kinds of situations: scientists who are trying to start on a new model organism and finding out things they never could have found out using mice or rats; or stories of fields of inquiry where people are coming up against a wall because they’re stuck using the easiest model organisms to use; or people who are making tremendous breakthroughs simply because they’re using the mouse, where you have such precise control of the genome. I started getting messages back with suggestions, and I started following up on those.

I also realized at a certain point that I was casting for topic areas of research. For example, tuberculosis research was one I landed on. I was also casting for characters: scientists I thought were interesting or especially smart, and able and willing to talk about these issues and about the big picture. And then the last thing I was casting for was the animals themselves—that’s how I ended up with the naked mole rats in Part III of the series. They’re just so charismatic that I realized they could be great characters in themselves.

Slate stories tend to take a strong point of view, and this series is no exception. Did you go into reporting this story with a strong point of view in mind, or did that evolve through your reporting?

I came in with a strong point of view that was based on my reporting from earlier. I had to convince myself in the course of reporting it that the point was worth making and not crazy. I mean, you talk to a former head of the NIH and now head of the National Cancer Institute and he doesn’t think it’s such a big problem, and if you’re a rational human being, you think, “I should just scrap this project because this person who probably knows more about this topic than anyone in the world doesn’t think it’s a particular problem.” I did have those thoughts constantly, but I wanted to balance them against all the other people I talked to who did think it was a problem. So while I sometimes had doubts and was trying to figure out how certain I was that this was worth making a big deal out of, I never felt like I was completely on the wrong track. I always felt like what I was saying was true; it was just a question of, is this going to destroy science as we know it, or is it a mildly interesting problem? Where between those two crazy points of view am I?

How did you resolve that issue? What made you decide that the story was in fact worth pursuing?

Once I got the assignment, I wasn’t going to walk away from it—so these were questions from before I even chose this story. That’s one thing about the way we do this at Slate, where you get a month off—once you’re on your month off, there’s no safety net. You have to do it. I guess if you’re taking a flyer on something, maybe there are times when you need to just commit to it, and then figure it out. I thought this was a long shot when I pitched it. I pitched it thinking maybe this is going to be rejected because it’s simultaneously too big and too small—because it’s kind of a niche question and because I didn’t have a narrative. But once David said he was interested in the idea, then I went ahead with it, and quitting was not an option.

But at the end, just as I was finishing, I did have this fear… I’m sure this will be familiar to other science journalists. Scientists are so understated and want to make sure that nothing that’s reported about their work is too sensationalistic. I tend to really internalize that and then I get really nervous about making big statements about the science that I’m writing about, and my editors are always pushing me to make the points bigger. Especially in this series, where Part I of the three is essentially a manifesto, there was some back and forth about how much heat to have in the manifesto. The first version was much tamer than the final version, and that made me anxious because I thought, “What if I turn up the heat and the people I talked to think I went crazy, or other scientists read it and think I was just frothing at the mouth?”

How did scientists respond to the final version?

The response I got from scientists was the most gratifying response that I’ve gotten for a science piece. Scientists, like all specialists, can sometimes be very nitpicky when they leave comments on your article pages or send you emails, but I didn’t get that kind of response. I got very, very thoughtful responses, including a lot of people saying that they were glad that this issue, which seems so nerdy and specific to biomedicine, was being written about in a general-interest magazine.

What was hardest about reporting and writing this series?

I think the hardest thing about reporting it was starting with the argument and finding the story, instead of doing it the other way around, which I think is probably the smarter, better way to do journalism, all things considered.

The hardest thing about writing it was trying to provide some honest-to-goodness science journalism about the various topics—explaining some of the science of tuberculosis while making this bigger point about how biomedicine is done. How do I write about TB research without losing track of the bigger point?

What was your solution?

I tried to focus on the animals because I think people find animals engaging and because that’s what tied everything together. I tried to keep the mouse and the mole rats front and center.

The other really hard part was the places where I tried to pull back and give some grand progression of the history of science. That section on lumpers and splitters—I found that very, very hard to write. I felt like, “Who am I to try to summarize the history of science in three paragraphs?” I felt like a jerk writing those sections, and hated doing it. The solution, or rather more like a cheat, was to use the concept of lumpers and splitters [to explain part of the history of science]. For example, I could talk about how the Black-6 mouse was kind of a tool for lumping. I shoehorned a lot of the history of the science into that discussion.

One thing that was striking about this story for me was the scope of its historical sweep. How did you gather and sort out all that historical material?

I had historian sources. I had the advantage of having access to a wonderful book called Making Mice, by Karen Rader, who is an historian of science. She went into great detail on the history of Jackson Lab and Clarence Little. I also have a good friend who is an historian of science and specializes in animal studies, who gave me a custom-made syllabus of journal articles on the making of model organisms. And then I talked to a lot of historians of science who have worked on these questions.

The history of mazes was really daunting. I just poked around until I found a specialist who had looked at this question, who could tell me what to look for. To start, I talked with a woman named Jacqueline Crawley at the National Institute of Mental Health, who is an expert on mouse phenotyping. She’s been running mice and rats through lab tests for 40 years, so she just knew a lot about mazes. And she also knew which scientists in the world are still using the old-fashioned rat mazes; she directed me to a couple of those, and it turned out that one of those people had just written a review of the history of mazes in research. I also went back to the primary sources looking at some of the early papers using mazes, which was a lot of fun.

In Part II of the series, you provide detailed descriptions of Jackson Lab, one of the world’s biggest breeding facilities. Why did you decide to paint such a vivid picture of the place where mouse breeding takes place?

That was kind of my idea from the outset; I wanted to find some stories of scientists working with different kinds of animals—mice and not—and I also wanted to go into the mouse factory. I was just fascinated by this idea that these are called breeders, but they function like factories; they’re producing animals that are each genetically identical to the others, so they’re like widgets off an assembly line. I just wanted to see what these factories looked like. I used to do some animal research and I’ve seen animal rooms at university labs, but I wanted to see what industrial lab animal breeding looked like.

You spent a lot of time traveling for this piece, reporting at breeding and distribution facilities and at university research labs. Did you start writing as you were reporting, or did you do all your reporting and then sit down to write?

I did all of my reporting and then sat down to write. This was something different than I did in 2009. I’m an amateur at doing these long projects because most of what we do at Slate is shorter pieces. So in 2009, I had taken a giant mountain of notes, and I went through and highlighted the key things from this giant stack of printouts, using different highlighters, then recombined them according to what could be part of what section. For this go-round, I printed out all my notes, but I avoided reading them through, for a very specific reason. The first time I went through this, I was kind of in awe of and in love with the amount of work that I’d put into the reporting. I’d go through my notes and go, “Oh yeah, this little detail! That has to go in Part Four!”

By not doing that this time, but instead just having my stack of notes next to me like a security blanket and then coming up with my outline, I think I gravitated toward what was most important. I think it’s really useful to try to set up the structure of the piece before you start digging through your notes, because otherwise you’ll find too many little chunks that you just kind of like—and then that ends up determining the structure, instead of what would be more natural as a structure.

What was your process for putting the story together? Do you use outlines?

In the past I’ve made outlines in Word or with pen and paper. This time I did something I liked that I’d never done before: I made up an Excel spreadsheet, changed the dimensions of the cells so they were big rectangles, able to have something like 10 lines of text apiece. Then I started plugging in paragraphs of ideas into these boxes. I liked doing it that way because it was more spatial, and with control-X and control-V I could just move an idea around on the page like big puzzle pieces. So I had sections of the piece running from left to right in my spreadsheet, with the progression of each piece running vertically. I had one of these for each piece in the series. That helped me a lot, and I changed the structure of this piece more than I have on any other I’ve worked on, I think in part because I was using this spreadsheet.

The other thing I tried very briefly, and am interested in trying more, was kind of a cure for writer’s block, especially for writing those historical sections: switching the font color to white. It’s like you’re typing in invisible ink. I tried it as a way to force myself to move forward because I’m one of those writers who tends to backtrack and self-edit as I go, in a counterproductive way. This was me trying to force myself to be the other kind of writer, who just throws everything on the page and sorts it out later.

Were there any pieces you really liked that ended up on the cutting room floor?

I had this whole thing I was working on about how it was that guinea pigs came to be the animal that in common speech we think of as the standard lab animal; but it’s not the case. Guinea pigs have been out of favor for decades, and I talked to this guy who is one of the last people to do research on tuberculosis using guinea pigs. He’s a great character and a great guy, and he describes himself as sort of an antiquarian. There was a point at the end where I thought I was going to include him—I thought the third section was going to be about naked mole rats and guinea pigs, and there was going to be a whole part of it about scientists who leave their lab spaces and go off into the wild to collect animals. There’s a great tradition of doing that, and I found a bunch of scientists who’ve done that. I had this elaborate outline, but I just realized as I was sitting down to write it that it would be much more effective to just pick one thing—I chose the naked mole rat because they’re so charismatic and because they’re kind of like the anti-mouse in a lot of ways—and just tell that story and let it stand in for all this other stuff. For someone who likes to go on and on and gets excited about all these little details, it was something I had to come to terms with, to pick just one tiny part and try to do it neatly in one piece. Maybe that’s why I’m so excited to talk about it now.

A glimpse behind the scenes:


Siri Carpenter Becky Appleby-Sparrow

Siri Carpenter is co-founder and editor-in-chief of The Open Notebook. Follow her on Twitter @SiriCarpenter.

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