"Most of studies in ecology are observational not experimental." Perhaps, perhaps not. Depends on who you ask. The point is really moot - if your system is amenable to manipulation, a proper experiment is invaluable. Most field ecologists are dealing with systems that are not easily manupulated. Does this mean they can't do good science, because they are dealing with many intercorrelated gradients that complicate matters? I think not. As Nick Gotelli once told me when I was an impressionable PhD student, "Galileo never moved a star". Kind of sums it up. "Imagine testing the hypothesis of past competition on Darwin finches under the H-D method. " Not sure what H-D is, may have missed it, but regarding Darwin's finches, I think what you are saying is that an experiment can't be conducted that will answer the question of competition past. True, but an accumulation of evidence from a variety of studies spanning behavioral ecology to phylogenetics gives us a pretty strong theory concerning their evolutionary ecology. Of course, something to the contrary could conceivably come up that might make biologists reconsider things. But it ain't happened yet. Pretty strong science I think. However, you might say, but the competition past question still stands... True, science does not provide time machines. I think you might be getting a little hung up on Popper and the role of statistics. Conceptually, I have no problem with Popper, but it's a very narrow view. Stats are useful, but they are just a means to an end and can be easily misused. Likwise, it's important to not confuse the stats with the underlying question! , which is often much more complex than a p-value.
Chris ************************************** Dr. Christopher Taylor Professor, Aquatic Ecology Department of Natural Resources Management Texas Tech University Lubbock, TX 79409 ________________________________________ From: Ecological Society of America: grants, jobs, news [[email protected]] On Behalf Of Manuel Spínola [[email protected]] Sent: Monday, February 28, 2011 8:49 PM To: [email protected] Subject: Re: [ECOLOG-L] Hypothesis Testing in Ecology Hi Martin, If you state a scientific hypothesis you need to derive predictions from it, and sometimes you can state the predictions as statistical hypotheses, but not always, in fact, Karl Popper was not thinking on statistics or statistical hypotheses. As Malcolm McCallum said if you use statistics to test a scientific hypothesis I think you are in a more shaking ground, statistics has its own problems. By the way, statistics is inductive. Some people are using information theoretic approaches like AIC (Akaike Information Criterion) to work with what they believe are scientific hypothesis but I don't think so. They have a set of models but not necessarily a set of scientific hypotheses. Other problems of working with hypothesis in ecology are the multicausality of ecological phenomena and the limitation of conducting experiments at some spatial and time scales. Most of studies in ecology are observational not experimental. More on Popper. Karl Popper did not believe that the theory of evolution by natural selection was a scientific theory. He argument that you cannot falsify an hypothesis derived from that theory. How do you falsify that hypothesis using a "critical experiment" as the H-D followers call it? Best, Manuel On 28/02/2011 05:16 p.m., Martin Meiss wrote: > I'm not sure I understand Manuel's distinction between statistical > hypootheses and scientific hypothesis. Is not the former supposed in some > way to mathematically embody/parameterize the latter? > But in any case, it seems to me that it is often hard to rigorously > formulate a null hypothesis and a corresponding working hypothesis. Suppose > you hear an account where someone had a feeling of foreboding about his > mother, only to discover later that just when he was having that feeling, > his mother, thousands of miles away, had suddenly died. When people tell > stories like this, it's often followed with a challenge, like "you can't > tell me that's just a coincidence!" > Well, I'd like to say it is a coincidence, but how could you test > it? What is the expected number of times you should have a feeling of > foreboding about your mother and she DOESN'T die? What is the expected > number of times mothers should die without their sons/daughters having > feelings of foreboding? How close to the actual time of death does the > feeling of foreboding have to be before we can count it? How creepy does a > feeling have to be before it reaches the threshold of genuine foreboding? > Now, this doesn't sound very ecological, but I'll bet readers of this > listserv can come up with examples from biology that approach this level of > nebulosity. Here's my stab at it: How K-selected must an organism be before > we say it is K-selected (or r-selected). How many factors in an environment > must conduce to K-selection before we say it is a K-selecting environment? > How many species in that environment must bear the earmarks of K-selection > before we accept the hypothesis that it truly is a K-selecting environment? > What about all the species in that environment that don't appear to be > K-selected? > I realize, of course, that different organism may be responding to > different factors in the environment, and that we can get around some of > these problems by defining a hypotheses sufficiently narrowly. However, the > more narrowly we define the hypothesis, the less it tells us about nature > because it is less generalizable, and I suppose that most researchers would > like to come up with insights that are generalizable. > I don't know if this relates to some of the problems that prompted > Jane's query, but I'd love to see your thoughts on the matter. > > Martin M. Meiss > > 2011/2/28 Shermin ds<[email protected]> > >> I like Manuel's response. >> >> To answer Jane's other questions: >> 1. Does it help you do better science? >> It can, but not necessarily. See below. >> >> Is it crowding out other approaches? >> I'd like to hear more about this - what other systematic approaches are >> there? For example, anecdotal observations are generally discouraged, but >> sometimes anecdotal observations are valuable and should be a) reported and >> b) inspire further observation and/or experiment. E.g. observations of >> tool-use in animals in the wild are great example of spontaneous events >> that >> one can never set out to observe systematically (except in controlled lab >> settings) but are nonetheless highly informative. >> >> I also wonder about replication - the larger or longer the scale (e.g. >> ecosystem, biome/longitudinal studies) the harder it is to replicate. This >> gets at Manuel's distinction about statistical vs. scientific hypotheses. >> You might have a hypothesis about a process but observe outcomes that are >> inherently difficult to attach a p-value to or find multiple examples of. >> Thoughts on that? >> >> Finally there's the issue of taxonomic poverty. Hypotheses about clades >> with few species are more difficult to test than those with a greater >> number >> of species. A problem if you're interested in the species-poor clade for >> other reasons. I.e. there is a trend towards choosing your species/system >> of >> study based on your questions of interest, and lately I've heard many talks >> that begin "We chose to study species X because it is an excellent model >> for >> testing Y..." What if you simply want to know about species X for no other >> reason than that you want to know about it? >> >> 2. Have you ever had a grant proposal or publication declined because >> of an absent or unclear hypothesis? >> >> Yes, and I'm wondering about this trend in the stated aims of some journals >> as well. >> >> -- >> Shermin de Silva, Ph.D >> http://elephantresearch.net/fieldnotes >> http://www.sas.upenn.edu/~sdesilva >> >> >> >> On Mon, Feb 28, 2011 at 10:49 AM, Manuel Spínola<[email protected] >>> wrote: >>> Dear Jane, >>> >>> That is a topic that have interested me for a long time. I teach >> something >>> of this in my classes to master students in wildlife management and >>> conservation here in Costa Rica. I know this is a controversial issue. >>> >>> First I recommend these 3 books: >>> >>> Scientific Method for Ecological Research. E. David Ford. >>> >>> Method in Ecology: Strategies for Conservation. Kristin S. >>> Shrader-Frechette and Earl D. McCoy >>> >>> A Primer on Natural Resource Science. Fred S. Guthery >>> >>> >>> Is necessary to distinguish between statistical and scientific >> hypothesis. >>> Statistical hypotheses is about patterns, scientific hypotheses are about >>> process (they are based on "why" or "how"). >>> >>> My experience on this topic tells me that most ecologists do not know the >>> difference between the 2 kind of hypothesis. >>> >>> Like you probably experienced, reviewers like to see hypothesis driven >>> research on the proposal that you submit but most of the time they do not >>> know what a true scientific hypothesis is. >>> >>> Most research in ecology is not hypothesis driven, even when would like >> to >>> see that. Read any paper in ecological journals and see how many of them >>> are truly hypothesis driven. >>> >>> Hypothesis driven research are not always possible and in many instances >> is >>> not necessary to have scientific hypothesis, all depend on the context. >>> Most of the time we are interested in parameter estimation on how much a >>> factor or covariable influence a parameter of interest. Besides, If you >> are >>> going to do hypothesis driven research you need to work with multiple >>> hypothesis (Chamberlin). >>> >>> Falsification is the contribution of Karl Popper to the >>> Hypothetic-Deductive method. It has nothing to do with statistics or >>> statistical hypothesis. >>> >>> The hypothetic-deductive method has been considered as "the scientific >>> method", however not many people know how it works. The >>> hypothetic-deductive method is inductive and not deductive like the >>> namesuggest. >>> >>> There is no a superior approach to obtain scientific knowledge. >>> >>> There are much more on this topic but I would like to see other opinions. >>> >>> Best, >>> >>> Manuel Spínola >>> >>> >>> >>> On 27/02/2011 11:44 p.m., Jane Shevtsov wrote: >>> >>>> Fellow Ecologgers, >>>> >>>> Lately, I've been thinking a lot about the role of hypothesis testing >>>> (both the statistical and falsificationist varieties) in biology in >>>> general and ecology in particular. Before saying anything, I want to >>>> ask the forum a few questions. >>>> 1. What do you think of the current emphasis on hypothesis-driven >>>> research? Does it help you do better science? Is it crowding out other >>>> approaches? >>>> 2. Have you ever had a grant proposal or publication declined because >>>> of an absent or unclear hypothesis? >>>> 3. Have you ever recommended that someone else's grant proposal or >>>> publication be declined for that reason? Was it the main reason? >>>> >>>> I look forward to hearing what people have to say. >>>> >>>> Jane Shevtsov >>>> >>>> >>> -- >>> *Manuel Spínola, Ph.D.* >>> Instituto Internacional en Conservación y Manejo de Vida Silvestre >>> Universidad Nacional >>> Apartado 1350-3000 >>> Heredia >>> COSTA RICA >>> [email protected] >>> [email protected] >>> Teléfono: (506) 2277-3598 >>> Fax: (506) 2237-7036 >>> Personal website: Lobito de río< >>> https://sites.google.com/site/lobitoderio/> >>> Institutional website: ICOMVIS<http://www.icomvis.una.ac.cr/> >>> -- *Manuel Spínola, Ph.D.* Instituto Internacional en Conservación y Manejo de Vida Silvestre Universidad Nacional Apartado 1350-3000 Heredia COSTA RICA [email protected] [email protected] Teléfono: (506) 2277-3598 Fax: (506) 2237-7036 Personal website: Lobito de río <https://sites.google.com/site/lobitoderio/> Institutional website: ICOMVIS <http://www.icomvis.una.ac.cr/>
