Time to put significance out of its misery

28 07 2014

If you’ve been following this blog for a while, you’ll be no stranger to my views on what I believe is one of the most abused, and therefore now meaningless, words in scientific writing: ‘significance’ and her adjective sister, ‘significant’. I hold that it should be stricken entirely from the language of science writing.

Most science writing has become burdened with archaic language that perhaps at one time meant something, but now given the ubiquity of certain terms in most walks of life and their subsequent misapplication, many terms no longer have a precise meaning. Given that good scientific writing must ideally strive to employ the language of precision, transparency and simplicity, now-useless terminology should be completely expunged from our vocabulary.

‘Significance’ is just such a term.

Most interviews on radio or television, most lectures by politicians or business leaders, and nearly all presentations by academics at meetings of learned societies invoke ‘significant’ merely to add emphasis to the discourse. Usually it involves some sort of comparison – a ‘significant’ decline, a ‘significant’ change or a ‘significant’ number relative to some other number in the past or in some other place, and so on. Rarely is the word quantified: how much has the trend declined, how much did it change and how many is that ‘number’? What is ‘significant’ to a mouse is rather unimportant to an elephant, so most uses are as entirely subjective qualifiers employed to add some sort of ‘expert’ emphasis to the phenomenon under discussion. To most, ‘significant’ just sounds more authoritative, educated and erudite than ‘a lot’ or ‘big’. This is, of course, complete rubbish because it is the practice of using big words to hide the fact that the speaker isn’t quite as clever as he thinks he is.

While I could occasionally forgive non-scientists for not quantifying their use of ‘significance’ because they haven’t necessarily been trained to do so, I utterly condemn scientists who use the word that way. We are specifically trained to quantify, so throwing ‘significant’ around without a very clear quantification (it changed by x amount, it declined by 50 % in two years, etc.) runs counter to the very essence of our discipline. To make matters worse, you can often hear a vocal emphasis placed on the word when uttered, along with a patronising hand gesture, to make that subjectivity even more obvious.

If you are a scientist reading this, then you are surely waiting for my rationale as to why we should also ignore the word’s statistical meaning. While I’ve explained this before, it bears repeating. Read the rest of this entry »

Ecology is a Tower of Babel

17 09 2012

The term ‘ecology’ in 16 different languages overlaid on the oil on board ‘The Tower of Babel’ by Flemish Renaissance painter Pieter Bruegel the Elder (1563).

In his song ‘Balada de Babel’, the Spanish artist Luis Eduardo Aute sings several lyrics in unison with the same melody. The effect is a wonderful mess. This is what the scientific literature sounds like when authors generate synonymies (equivalent meaning) and polysemies (multiple meanings), or coin terms to show a point of view. In our recent paper published in Oecologia, we illustrate this problem with regard to ‘density dependence’: a key ecological concept. While the biblical reference is somewhat galling to our atheist dispositions, the analogy is certainly appropriate.

A giant shoal of herring zigzagging in response to a predator; a swarm of social bees tending the multitudinous offspring of their queen; a dense pine forest depriving its own seedlings from light; an over-harvested population of lobsters where individuals can hardly find reproductive mates; pioneering strands of a seaweed colonising a foreign sea after a transoceanic trip attached to the hulk of boat; respiratory parasites spreading in a herd of caribou; or malaria protozoans making their way between mosquitoes and humans – these are all examples of population processes that operate under a density check. The number of individuals within those groups of organisms determines their chances for reproduction, survival or dispersal, which we (ecologists) measure as ‘demographic rates’ (e.g., number of births per mother, number of deaths between consecutive years, or number of immigrants per hectare).

In ecology, the causal relationship between the size of a population and a demographic rate is known as ‘density dependence’ (DD hereafter). This relationship captures the pace at which a demographic rate changes as population size varies in time and/or space. We use DD measurements to infer the operation of social and trophic interactions (cannibalism, competition, cooperation, disease, herbivory, mutualism, parasitism, parasitoidism, predation, reproductive behaviour and the like) between individuals within a population1,2, because the intensity of these interactions varies with population size. Thus, as a population of caribou expands, respiratory parasites will have an easier job to disperse from one animal to another. As the booming parasites breed, increased infestations will kill the weakest caribou or reduce the fertility of females investing too much energy to counteract the infection (yes, immunity is energetically costly, which is why you get sick when you are run down). In turn, as the caribou population decreases, so does the population of parasites3. In cybernetics, such a toing-and-froing is known as ‘feedback’ (a system that controls itself, like a thermostat controls the temperature of a room) – a ‘density feedback’ (Figure 1) is the kind we are highlighting here. Read the rest of this entry »

Biowealth – a lexical leap forward for biodiversity appreciation

17 12 2010

Here’s a little idea I’ve been kicking around in my head that I’d like to invite you to debate. Call it an ‘Open Thread’ in the spirit of BraveNewClimate.com’s successful series.

© The Economist

Let’s face it, ‘biodiversity’ is a slippery and abstract concept for most people. Hell, even most ecologists have a hard time describing what biodiversity means. To the uninitiated, it seems simple enough. It’s just the number of species, isn’t it?

Well, no. It isn’t.

Unfortunately, it’s far, far more complicated. First, the somewhat arbitrary pigeon-holing of organisms into Linnaean taxonomic boxes doesn’t really do justice to the genetic gradients within species, among populations and even between individuals. We use the pigeon-hole taxonomy because it’s convenient, that’s all. Sure, molecular genetics has revolutionised the concept, but to most people, a kangaroo is a kangaroo, a robin is a robin and an earthworm is an earthworm. Hierarchical Linnaean taxonomy prevails.

Then there’s the more prickly issue of α, β and γ diversity. α diversity essentially quantifies species richness within a particular area, whereas β diversity is the difference in α diversity between ecosystems. γ diversity is used to measure overall diversity for the different constituent ecosystems of a region. Scale is very, very important (see our recent book chapter for more on this). Read the rest of this entry »