Ecologists study lots of different things, and those things vary a lot in all sorts of ways. No two sites/times/organisms/populations/communities/ecosystems/species/landscapes/food webs/whatevers are exactly alike. Should ecologists seek generalities about the diverse, heterogeneous stuff they study? If so, what kinds of generalities should they seek and how should they seek them? Those are questions on which prominent ecologists have long disagreed. But the views of a few prominent ecologists might well be unrepresentative of the views of ecologists collectively, for the same reasons that the loudest voices in any discussion might not be representative of the views of everyone in the room. So to get a bit of data, I polled y’all on these questions. Here are the results!
As with all our polls, this isn’t a random or representative sample of all ecologists, or even of all readers of this blog. But it’s a big and diverse enough sample of ecologists to be worth talking about. I found the results very interesting, and a couple of them surprised me. They were so interesting I even went to the trouble of doing a PCA and making a pretty graph, as if I was Meghan or something. 🙂 So you should totally read on.
Reminder of the poll questions
The poll listed nine approaches to generality:
- Universal or nearly universal patterns or “laws”
- Simple theoretical models
- Statistical attractors
- “High level” theoretical frameworks
- Fruitful analogies
- Model systems
- Distributed experiments
- Long-term studies
Respondents were asked which of these they used in their own work (if any), with an option for “other”. Respondents were also asked how important is is for ecologists collectively to use each of those approaches to generality (unimportant, somewhat important, or very important, with an option for don’t know/not sure/no opinion).
We got 116 respondents. They’re a mix of faculty (49%), postdocs (19%), grad students (18%), non-academic professional ecologists (10%), and others (4%). They mostly do either basic research (38%), or a mix of basic and applied research (50%); only 12% just do applied research.
Results and commentary
Almost all ecologists seek or use multiple forms of generality in their own work. The modal respondent uses 4 of the 9 approaches to generality polled; the average respondent uses almost 5, and the max is 8. Only 4% of respondents indicated that they do not seek generality in their own work. So here’s the first interesting result. Contrary to the claims of some opinion pieces you might have read, ecologists who focus in laser-like fashion on the unique particularities of their own study system are a very small minority (or else were really undersampled by this poll, I guess…).
There weren’t any big differences among different sorts of ecologists in terms of the number of approaches to generality they use. Faculty and postdocs use slightly more approaches than grad students on average, which makes sense. More experienced researchers have had more time to use a greater range of research approaches during their careers. Applied researchers use slightly fewer approaches to generality than other researchers do, but I wouldn’t make much of this because it’s a small sample size.
Nobody chose “other” for the approaches to generality they use, which indicates that my list of 9 approaches to generality was pretty complete, at least in the minds of the poll respondents. Though I wonder a little if that would’ve remained true even if I’d listed fewer options…
Some approaches to generality are much more popular than others.
Fig. 1, below, shows the proportion of poll respondents saying each approach to generality was “very important” for ecologists to use, vs. the proportion saying it was “unimportant”. So the most important approaches to generality for ecologists to use are in the upper-left, the least important are in the lower right. These calculations ignored the rare respondents who expressed no opinion on the importance of a given approach.
According to the respondents, long-term studies are the most important approach to generality, regarded as very important for ecologists to use by 84% of respondents, and as unimportant by only a trivially small fraction. Next come several approaches with similar results: meta-analysis, distributed experiments, simple theoretical models, high-level theoretical frameworks, and universal laws/patterns. All were regarded as very important by 57-70% of respondents, and as unimportant by only a few. Bringing up the rear are three much less popular approaches to generality, though none were unpopular in an absolute sense: statistical attractors, model systems, and fruitful analogies. These were the only three approaches to generality regarded as very important for ecologists to use by only a minority of respondents (about 1/3 in each case). And they were the only three approaches to generality regarded as unimportant by an appreciable fraction of respondents with an opinion (up to 19% in the case of fruitful analogies).
Those results confirm my anecdotal impressions. Disappointingly to me (and to Tony Ives, I presume), ecologists mostly don’t seem to care all that much about analogies between ecological and non-ecological systems, or between very different-seeming ecological systems. I think recognizing and formalizing such analogies is both a lot of fun, and a powerful way to learn about ecology, but apparently I’m in a minority on that. And ecologists mostly don’t think that it’s particularly important to seek generality by working in model systems, so there’s another respect in which I’m in the minority. And as Brian predicted, the notion that some common patterns in ecological data might have statistical rather than ecological explanations is not a notion that many ecologists think it’s important to pursue (it’s also a controversial notion, as Brian can attest).
The most important approaches to generality are the most commonly used–with one big exception.
Why are some approaches to generality regarded as much more important to use than others? We can get some insight by looking at which approaches to generality ecologists use themselves. Fig. 2, below, plots the proportion of respondents saying that an approach to generality was “very important” for ecologists to use, against the proportion using that approach in their own work.
Notice that there’s a very tight positive correlation between the proportion of respondents who use a given approach to generality themselves, and the proportion who say it’s very important for ecologists as a group to use. No surprise there: people mostly like their own approaches and think that others should adopt them. (Though that’s not all that’s going on here; I’ll come back to that…). But there’s one big outlier: distributed experiments, the most rarely-used approach in the poll but one that a solid majority of respondents think it’s very important for ecologists to pursue. Apparently, not that many people are part of NutNet, but lots of people wish they were! 😉 I was surprised by this result. In other polls we’ve done on research approaches in ecology, it is unheard of for ecologists as a group to think so highly of any research approach that so few of them use themselves. I think that’s a big compliment to the NutNet founders and other pioneers of distributed experiments in ecology. And probably a sign that we can look forward to much more distributed experimental work in future.
Ecologists tend to want other ecologists to use widely-used approaches, even if they don’t use those approaches themselves. And they tend not to want other ecologists to use rarely-used approaches, even if they use those approaches themselves.
Look again at Fig. 2. Notice that all the points fall above the 1:1 line. That is, it’s not the case that respondents think it’s very important for ecologists to use all and only the approaches to generality that they themselves use. It’s not that everybody’s saying “all ecologists should do exactly as I do”. Rather, most respondents said that at least one approach to generality that they don’t use themselves is very important for ecologists as a group to use.
Further, the more widely-used an approach to generality is, the more likely it was to be cited as “very important” for ecologists to use by people who don’t use it themselves (with the already-noted exception of distributed experiments). That’s a big part of why the points towards the right-hand end of the x-axis in Fig. 2 are further above the 1:1 line than are points towards the left-hand end.
But even that’s not the end of the story. Because it’s also the case that people who use rarely-used approaches to generality are less likely than others to say that their own approaches are very important for ecologists to use. Only a bit over 50% of respondents who use fruitful analogies said that that approach is very important for ecologists to use. The same was true for respondents who use model systems and statistical attractors. In contrast, 3/4 or more of respondents who use every other approach to generality also said that approach was very important for ecologists to use.
All this echoes results from other polls of ours: ecologists tend to want others to use the most widely-used approaches in the field, because they use those approaches themselves and also if they don’t. Conversely, ecologists are tend not to want others to use little-used approaches, because they don’t use those approaches themselves and also if they do. I think these results illustrate just how profoundly our own individual judgments as to how ecologists ought to do ecology are shaped by how ecologists actually do ecology. It can be hard to zig when everyone else is zagging. It’s even harder to think that everyone else should zig when they’re actually zagging–even if you yourself are zigging.
Some approaches to generality are less widely-used because applied ecologists don’t use them.
Figure 3, above, shows a PCA on the approaches to generality that respondents use themselves. Data were centered and standardized to subtract out variation among respondents in how many approaches to generality they use, so as to focus attention on variation among respondents in which approaches they use.
Figure 3 shows that applied ecologists all fall towards the left end of PC 1. That’s because hardly any of the applied ecologists who took this poll use statistical attractors, universal patterns/laws, high-level theoretical frameworks, or fruitful analogies in their own work. Those approaches, along with simple theoretical models, all load positively on PC 1. So, part of the reason why statistical attractors and fruitful analogies are not as widely-used as other approaches to generality is because applied ecologists mostly don’t use them.
Fig. 3 also illustrates that no one PC axis explained more than a modest fraction of the variation in the standardized usage data. Usage of any given approach to generality isn’t all that strongly correlated with usage of any other approach in this dataset. Which is actually kind of interesting; that surprises me a little. For instance, I’d have thought that ecologists who work on universal laws/patterns would also tend to use simple theoretical models, and vice-versa. Apparently not.
There was no appreciable variation in which approaches to generality ecologists use that was associated with their employment (faculty vs. postdocs vs. grad students vs. etc.)
I took my own poll. I was a bit of an outlier in saying that every single approach on the list was very important for ecologists to use. I agree with Richard Levins in thinking that it’s best for ecology as a whole to use a (very) mixed strategy, whether we’re pursuing “generality” or any other research aim.
What do you think of all this? Looking forward to your comments.