Musings on reading older literature (UPDATED)

It’s common for senior ecologists to complain that ecologists these days don’t read the older literature enough. But of course, like many problems with kids these days, the “problem” may be one of perception rather than reality. I have no idea if ecologists these days read the older literature any more or less than they used to (anyone have data on that?) But I do have some thoughts on why one might want to read the older literature–or avoid it!

Probably the best and most common reason to read the older literature is that otherwise you can’t understand the current literature. Think of foundational papers for instance.

Here’s another clear-cut reason to read the older literature: you need to read all that’s known about some specific topic. Meg has a good post on this.

UPDATE: Can’t believe I forgot a third reason: some classic papers are so rich in insight that you can keep returning to them over and over. Meg has a good post on this.

But in other circumstances, it’s not so easy to decide what to read. Tradeoffs and opportunity costs are everywhere. Time spent reading old stuff is time not spent reading new stuff, or doing something else worthwhile. So you can’t just bemoan how nobody reads the older literature anymore unless you also say what everybody should be doing less of, so as to free up time to read more older literature. Especially if by “older literature” you mean “stuff that was new when I was a student.” 🙂

There’s a difference between reading older papers and evaluating them. It’s possible to have both too little and too much respect for older papers. Obviously, if you’re ignorant of the history of your field, you’re at serious risk of reinventing the wheel, or making a big mistake that someone who knew the older literature would never make. But less obviously, if you have too much respect for the older literature, you’ll be too quick to dismiss novel work that actually advances the field. For instance, zombie ideas persist in part because of reflexive citation of “classic” papers that have since been refuted or superseded. I think the way to square this circle is to read critically. So that familiarity with the older literature doesn’t shade over into excessive respect for the older literature. (You should read new papers critically too, of course)

Following on from the previous thought: novelty is a matter of degree. There’s a continuum from “that’s already been done” to “that’s totally novel”. At the former end are things like rediscovering known proofs of mathematical theorems. If you’re unaware a theorem’s already been proven, and so prove it again in the same way, you’ve wasted your time. At the latter end is stuff like Einstein’s work on relativity. But most new work falls in the mushy middle–building on, refining, extending, or revisiting older work. So that the newness of the new work becomes a contestable judgment call.

Part of what makes those judgment calls difficult is that it’s often very easy to read modern views back into older literature. As modern readers, we tend to notice, and be impressed by, old passages that sound modern. Even if the passage is a brief sketchy version of something that’s now much more fully worked out. And even if the apparent modernness of the passage represents a misreading on our part. Darwin’s Origin is a good example. It’s very easy to misread Darwin as having a correct, modern understanding of how isolation and divergent selection contribute to speciation. He didn’t (at least, I don’t think so–feel free to push back in the comments). And although we see Darwin as hugely original, remember that back in his own time some people accused him of being unoriginal. Claiming that the notion of natural selection was already in Blyth, or Wells, or Matthew, or Hutton. And that the notion of evolution was already in his grandfather Erasmus’ poetry, or Buffon, or the classical Greeks. Critics of Darwin’s originality were wrong. But that they existed at all is an illustration of how slippery a concept “novelty” is.

I now think one of my own papers is an example of excessive attention to, and respect for, older literature that has since been superseded. Fox and Olsen (2000 Oikos) takes as its starting point a somewhat famous but frankly rather strange theoretical paper of Robert MacArthur’s from 1955. It’s on the relationship between a food web’s “complexity” or “diversity” and its “stability”. As a grad student, I found the paper intriguing. I tried to figure out what exactly MacArthur (1955) meant and how it related to other things I’d read. Eventually, I thought I’d figured it out sufficiently well to have a testable hypothesis. But it’s not a method of hypothesis development that I’d choose again. My time would’ve been better spent focusing on more recent papers.

I’ve heard that in some scientific fields, there’s a culture of reading and citing older papers, and a collective sense of the field as a lengthy, ongoing conversation that you can’t join unless you’ve fully caught up on “earlier episodes”. This sort of culture has advantages and disadvantages (at least I’d think so; what I’m about to say is speculation on my part, informed by conversations with Brian and others). A culture of reading and citing older papers ensures that nobody reinvents the wheel. But it also risks closing the field off to worthwhile input from outsiders. Both input on the current topics of conversation, and input that would shift the conversation towards different topics. At its worst, you can imagine this kind of culture might deteriorate into navel-gazing and gatekeeping. (Note that I have no idea if any field actually is like this; I’m just raising possibilities). This sort of culture isn’t unique to scientific fields, and doesn’t arise solely from an appreciation for old scientific papers. There are bits of the blogosphere/twittersphere, including the scientific blogosphere/twittersphere, that have the feel of an ongoing private discussion among insiders. Those insiders sometimes react pretty harshly to any newbie who tries to join the conversation without first having spent an inordinate amount of time getting up to speed. I hope that the conversation at Dynamic Ecology is both an ongoing conversation that people will want to keep following and participating in, but also a conversation that newcomers feel free to join. Would welcome feedback on this.

Discussions of the value of reading older literature sometimes mix up the value of reading the older literature with the value of reading broadly. They’re orthogonal. Personally, I worry less about people not reading the older literature (though I do worry about that), and more about people not reading sufficiently broadly. I worry that in future, increasing use of filters like Google Scholar recommendations and social media won’t just cause people to read more narrowly, but will cause them to unconsciously redefine what I would consider narrow reading as broad reading.* I’d say you’re not really reading broadly unless you’re reading a fair bit of stuff that has nothing to do with anything you work on. Brad Anholt for instance once told me that he reads the introductions of every paper published in various leading ecology and evolution journals. It’s how he keeps up with current thinking in the field as a whole. That’s reading broadly. Even if you fall short of that ideal, I suggest reading outside your field in cognate fields dealing with conceptually-analogous problems. For instance, any community ecologist studying species coexistence should be at least passingly familiar with the population genetics literature on maintenance of genetic diversity. Not because of the possibility of eco-evolutionary dynamics, but just because “coexistence” is ultimately the same problem, whether it’s coexistence of species or coexistence of alleles.

So I dunno. Do we read enough older literature these days? Do we read broadly enough? You tell me. Looking forward to your comments.

*Note that my worry hasn’t come to pass yet. Judging by this poll, people currently use social media and other newfangled ways of finding papers to read as a supplement to, rather than replacement for, old school methods.

21 thoughts on “Musings on reading older literature (UPDATED)

  1. This is a really interesting question. I agree wholeheartedly about too much respect for old literature sometimes stifling creativity! (This is one of my excuses for being way, way, way behind on my reading ( I don’t know who else got this, but the other day I got a request to identify “5 papers every ecology grad student should read”, in support of an effort to list 100 of them. I haven’t replied yet, because I’m not sure I can come up with even a single paper that every student should read. Although I can probably think of a few of my own that no grad student should read….

  2. “I’d say you’re not really reading broadly unless you’re reading a fair bit of stuff that has nothing to do with anything you work on.”
    Ow. Not until I retired did I have any time for many years to read anything outside my field. This was common nostalgia that surfaced during coffee breaks with colleagues. Although we encourage students and post-docs to broaden their reading, most research leaders are surrounded by stacks of books and journal papers related only to current investigations. Non-topic reading assumes a dim light through the paper towel tube.

  3. I enjoy thinking about the question of how much/which old literature to read, and certainly there is too much to read to possibly keep up on it all and learn all the new stuff, especially if one works in interdisciplinary fields and/or has broad interests. And we can’t cite everything or even know about everything even if we have time to read it. So there is a wide spectrum of practices from those that say “Don’t bother reading anything but maybe our lab’s work.” to “Read everything and if you don’t and I catch you missing an obscure Russian reference, you’re doomed!”. I wander around somewhere in the middle of that spectrum but do try hard to keep up, and I love the literature; an obsessive collector.

    • It is certainly possible to be a good scientist and also be a mediocre scholar. And vice versa. I think students get a better appreciation of novel and exciting ideas if they understand the paradigms and sources of conventional wisdom. There may be examples of creative scientists (Feynman ?) that work better by routinely ignoring/questioning revealed wisdom.

      For a while I thought that people ignored earlier literature because pdf versions didn’t go back that far. That no longer seems to be the case. 🙂

      • @Wendell:
        Good point. There is a different strokes for different folks element to this. I fancy myself a bit of a Feynman–I think I’m reasonably good at questioning widespread assumptions and conventional wisdom. And I think that’s in part because I’ve read pretty broadly, and have never focused too much on any single line of research (it’s also in part for other reasons, like having a BA from a liberal arts college). But it’s an open question whether anyone who wants to can acquire those habits of mind by reading sufficiently broadly. Quite possibly, my way of working wouldn’t work for others, no matter what they chose to read. Certainly, other people’s ways of working wouldn’t work for me.

    • Good comments John–but you saved the best one for Twitter! 🙂

      Great point: today’s current literature is tomorrow’s older literature. So if you don’t think people today should bother reading older stuff, presumably you don’t think people tomorrow should bother reading your stuff.

      Note that I can imagine some people agreeing with that–freely admitting that their own work is not of lasting value (say, because the field changes too fast).

  4. Two neat examples that I’ve personally experienced…
    1) Reading the older literature can help to reveal whether your field has been based on or revolving around an untrue paradigm. The primary literature always stated that the enzyme that I work on wasn’t in animals. I discovered that it was in fact present in animals, but didn’t believe my result at first because I had internalized this dogma and accepted it as true. No one had explicitly examined whether the enzyme was in animals or not, but it somehow got into the literature that this was a fact even though no experiments had been conducted to test this assumption.
    2) I wrote an assignment once on antibiotic resistance and went back and read Alexander Fleming’s original paper on penicillin. What’s very cool about that paper is that he describes the discovery and the applications and then warns that bacteria will eventually become resistant to the antibiotic! He predicted the anti-biotic resistance crisis before the widespread clinical introduction of penicillin!

  5. Hey Jeremy, I found this a refreshing take on reading the literature because you actually provided reasons fro why reading broadly or deeply can be valuable. Too often it’s presented as a given that reading the literature is a must. Even asking why it’s necessary is often seen as antithetical to being a good scientist. In my mind there are two good reasons to read the literature – one, as you identified, to avoid trampling on well-trod ground. But this actually requires narrow reading – you come up with a new question or a possible new approach to an old question and then you check to see if anybody’s already done it. You focus only on papers that are directly related to the idea you have. Two, to get ideas. I’m amazed at how often I get ideas for questions or approaches to questions when I read papers. If I hit a dry spell for ideas, reading always gets me out of it. Other than those benefits I see reading the literature as being relatively unimportant. I’m probably at the extreme end on this but the parts of a paper I care about are the Results and the Methods. If you’ve addressed an interesting question in a rigorous and reliable way I don’t really care if you can put it in the context of other related research or motivate it based on the current literature. I’ll admit that you probably have a better chance of addressing an interesting question in a rigorous and reliable way if you’re reading the literature but I’m not sure what that reading looks like and it’s not clear to me how much of it you need.


    • “Two, to get ideas”

      Yes, absolutely. Peter Adler’s old guest post on how “it doesn’t get any easier” talks about this. About how he finds that, to come up with good research ideas, he needs to spend a lot of time reading.

  6. “I have no idea if ecologists these days read the older literature any more or less than they used to (anyone have data on that?)”

    I’ve no specific data to address that point but I do have an old post that suggests a reason why it night be the case, at least in my own field:

    One result of the massive increase in research in some fields is that postgrads are becoming more specialised in their topics, which is what I discuss. But another outcome could be that they read less of the older literature because they are too busy trying to keep up with more recent papers. That should be a testable hypothesis: is the average relative age of papers cited in the e.g. 70s, 80s, 90s, 00s, 10s getting progressively younger?

  7. Your discussion about scholarship and old citations vs. potential gatekeeping made me think about Fretwell’s paper on MacArthurs legacy (Annual review Ecol Syst, 1975, That paper touches on exactly this tension, and includes rather short and well-targetted reference lists as one of MacArthurs “influences” on ecological research. Maybe you’re already aware of the text though.

    “There is a great expanse between the minimal and the maximal number of references that are
    possible in a paper. Ecology as a whole has tended toward the maximal, but MacArthur leaned the other way, and reasonably so. The process of prediction making requires such strict logic that peripheral references merely distract. There is also the danger of high scholarship, which tries to settle issues by argument instead of by empirical testing. Few scientists realize how antithetic are scholarship and science. A Ph.D. who has been taught in a rich tradition of scholarship is tempted to use its techniques inappropriately, as an end in themselves, instead of using the literature just to clarify the process of making real-world tests. Consistent with his use of H-D science, MacArthur rarely used a broad literature base in his work.”

    I cannot really say if that’s a fair description of ecology pre-MacArthur, but thought that it serves as an interesting parallel. And yes, I’m aware of the irony of highlighting this point by using a paper from 1975.

    Overall I agree with the sentiment, in the sense that references (old and new) should serve a specific purpose (work as a building block), and not just be used to impress readers with how well-read you are. And too many tangential references can definitely make papers harder to read and more muddled. However, I do think it’s really important to provide references to foundational papers, as well as relevant hooks into the previous literature.

    • Cheers for this, I’m embarrassed to say I didn’t know that Fretwell paper. Very useful to me as I’m currently reading up on the history of ecology for a long-term project.

      • You’re welcome. I’m also working with a project that has recently sent me wading through older foundational papers, which is why I found it. Might have seen it through “Background of Ecology” by McIntosh.

  8. Pingback: While I was away… some recommended reads | The Lab and Field

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