Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Posting-Version: version B 2.10.1 6/24/83; site mit-athena.UUCP Path: utzoo!watmath!clyde!burl!ulysses!allegra!bellcore!decvax!mit-athena!jc From: jc@mit-athena.UUCP (John Chambers) Newsgroups: net.nlang Subject: Re: "Controlled experiment": redundancy or retronym? Message-ID: <213@mit-athena.UUCP> Date: Wed, 8-May-85 17:33:50 EDT Article-I.D.: mit-athe.213 Posted: Wed May 8 17:33:50 1985 Date-Received: Sat, 11-May-85 01:08:27 EDT References: <477@utai.UUCP> Organization: MIT Project Athena Lines: 74 The term "controlled experiment" is at least a century old in the scientific literature, and was adopted for good reason. "Experiment" wasn't originally a scientific term; it predates the development of the modern scientific method. And the modifier "controlled" is not just a buzz word to make it sound more scientific; it has a well-defined, very precise meaning. People have always been doing experiments, usually without any controls. Sometimes these experiments turn out to be useful anyway, but usually they just lead to "more research is needed" conclusions. The uncontrolled experiments I like are the ones that test evolutionary theory. Many people are taking part in such tests right now. Did you read the recent news about the Salmonella outbreaks in the Midwest? They have been traced back to resistant strains of bacteria that were forcibly evolved in area feedlots, by the simple technique of giving low doses of antibiotics to cattle. The result was to kill off the more susceptible bacteria, with only the resistant ones surviving each generation. These experiments do have controls, in a sense, since there are cattle around that are not being fed the antibiotics, and their bacteria are not evolving resistance. But the feedlot owners haven't been running a controlled experiment; the controls are owned by different people, and they differ in other ways (such as place of habitation, food sources, etc.) from the feedlot cattle. There's a less vital but funnier evolutionary experiment going on in most American cities. Owners of lawns have been selecting for short-stemmed dandelions for a long time by the simple method of mowing the flowers off of plants that have long stems. Short-stemmed races live in most American cities now, but their country cousins still have their flowers on long stems that are more likely to be visible to pollinators. It's especially interesting that most of the short-stemmed varieties grow longer stems about when the seeds ripen. We are evolving what is likely the planet's first lawnmower-distributed species. Again, this hasn't been a controlled experiment, because of the fact that the two populations differ in many other ways than just how they are mowed. There was an important uncontrolled experiment done back in the 40's and early 50's in a lot of hospitals, which has gotten some publicity in the scientific press. Many hospitals adopted the practice of putting premature babies into oxygen tents, for reasons that were never very clear. People though that it would help them somehow. Actually, it blinded a lot of them, and left many others with badly damaged sight. This amounted to a large scale experiment on the effects of high oxygen levels on infants. Unfortunately, there were no controls used, so it took years to collect the incriminating evidence, and the damage went on for years longer than it should have. This incident is very useful in arguments about the ethicality of "using people as experimental subjects". The fact is that using any unproven treatment amounts to experimenting on patients, but without controls, you are adding the extra insult of performing a bad experiment and sacrificing subjects unnecessarily. (Now if God had done a good job of designing this world, we'd never get sick or injured, and this would all be unnecessary. :-) -- John Chambers [...!decvax!mit-athena] He who has made no mistakes has probably made nothing at all.