But not ‘evolving’: bugs and the politics of medical language
February 28, 2007
Why are biomedical researchers reluctant to use the word “evolution”? That is the question asked by a fascinating article at PLoS Biology. ((Antonovics J, Abbate JL, Baker CH, Daley D, Hood ME, et al. (2007) Evolution by Any Other Name: Antibiotic Resistance and Avoidance of the E-Word. PLoS Biol 5(2): e30 doi:10.1371/journal.pbio.0050030)) Their findings are summarized in the abstract:
The increase in resistance of human pathogens to antimicrobial agents is one of the best-documented examples of evolution in action at the present time, and because it has direct life-and-death consequences, it provides the strongest rationale for teaching evolutionary biology as a rigorous science in high school biology curricula, universities, and medical schools. In spite of the importance of antimicrobial resistance, we show that the actual word “evolution” is rarely used in the papers describing this research. Instead, antimicrobial resistance is said to “emerge,” “arise,” or “spread” rather than “evolve.” Moreover, we show that the failure to use the word “evolution” by the scientific community may have a direct impact on the public perception of the importance of evolutionary biology in our everyday lives.
The authors proceeded by counting word-frequencies in a set of biomedical papers about antimicrobial resistance, compared with a set of papers from evolutionary biology. In the biomedical literature, they found, the word “evolution” (“or its lexemes such as ‘evolutionary’ or ‘evolving'”) was used 2.7% of the time to denote the appearance of antibiotic resistance, as against 65.8% of the time in the evolutionary literature. Instead, in the medical journals,
60.0% of the time antimicrobial resistance was described as “emerging,” “spreading,” or “increasing” (range 0%–86%, mode 30%–40%); in contrast, these words were used only 7.5% of the time in the evolutionary literature (range 0%–25%, mode 0%–10%). Other nontechnical words describing the evolutionary process included “develop,” “acquire,” “appear,” “trend,” “become common,” “improve,” and “arise.”
What might be the rationale behind such alternative terminology? The authors speculate:
The frequent use of the term “emergence” rather than “evolution” seemed more to be the result of a simplified phraseology that has “emerged and spread” out of habit and repeated usage. It may also be that many nonprofessional evolutionary biologists consider “evolution” to be a rather nonspecific word meaning “gradual change,” and that “emergence” more explicitly incorporates the component aspects of the evolutionary process, namely, mutation, recombination, and/or horizontal transfer of resistance. The word “spread” may, similarly, appear to incorporate the component processes of transmission, horizontal transfer, and increase in allele frequency. While these processes are recognized by professional evolutionary biologists as important aspects of evolutionary change, biomedical researchers may have the sense that the word “evolution” is itself too imprecise.
Well, we might point out that the word “evolution” did have a long history of other meanings – unrolling, unfurling, giving off (as of gas or heat), opening out, and development – before it was given its modern biological sense in the 19th century. ((OED gives its origin as Latin evolutionem, the unrolling of a book (in scroll format). So perhaps biological evolution is the unrolling of the Book of Life.)) And the word is still often used in other contexts to mean nonspecific “gradual change”, without any precise intention of a biological metaphor, for example when we say that a piece of music or a story is “evolving”. ((Though an implication of the scientific sense might be apt in some cases, particularly for music that works through obvious thematic “development”, or for the work of Philip Glass, who organises musical cells that undergo descent with modification.))
In defence of the biomedical authors, we might also add to the above list the hypothesis that, since they are not specialists in evolutionary biology, they prefer to leave the use of an overarching label for the phenomena they are studying to their colleagues in evolution proper. But this might not be a sufficient defence of their terminological behaviour. After all, it is not as though there is any other possible proposed mechanism than evolution for what they are seeing. And their alternative terms – emerge, spread, appear – may seem studiedly vague.
On the other hand, as the PLoS authors seem to imply, the biomedical researchers might be appealing to “emergence” in the scientific sense. “Emergent properties” in physics are properties such as colour or friction that are observed in a macro-sized object but are not properties of the component atoms; in biology “emergence” may describe the behaviours of flocking birds or ant colonies, or the self-organization of living systems in general, as well as changes in populations over time. In this way the use of “emergence” may indeed be meant to signal “evolution”. (It is not inherently any more vague a word.) But then, why not just say “evolution”?
It seems that in general, the preferred alternatives do Unspeak the underlying fact of evolution, even though they do not actually deny it. The PLoS authors emphasize that “We found no evidence that deliberate efforts were being made by medical researchers to deny that evolutionary processes were involved in the increase of antibiotic resistance.” But there might be other, political reasons for the verbal coyness:
It has been repeatedly rumored (and reiterated by one of the reviewers of this article) that both the National Institutes of Health and the National Science Foundation have in the past actively discouraged the use of the word “evolution” in titles or abstracts of proposals so as to avoid controversy. Indeed, we were told by one researcher that in the title of one proposal, the authors were urged to change the phrase “the evolution of sex” to the more arcanely eloquent wording “the advantage of bi-parental genomic recombination.”
“So as to avoid controversy.” That must be the pseudo-“controversy” over “Intelligent Design”. In the face of ID’s epistemological nihilism and methodological dishonesty, is it the right response for august national scientific bodies to recommend a retreat from the very word “evolution” itself? This is not just an obscure phenomenon of professional journals: the PLoS authors find that when the mass media report on scientific findings, they are guided in their use of the word “evolution” by how often it is used in the original paper. So a consequence of the biomedical avoidance of the word “evolution” is that the public is not reminded so often that bacterial resistance to antibiotics (and the consequent appearance of “Superbugs”) is a regular and spectacular confirmation of evolutionary theory. To fight the Unspeak of “Intelligent Design”, it might be necessary to insist forcefully on the Speak of “evolve”.