The first two examples are from "Click and Clack the Tappet Brothers" who host the program "Car Talk" on NPR. Specifically from the show of 17 May 2003, segments 5 and 6. They are summarized here. Much of the data was obtained when the caller would answer questions posed by the hosts. The other examples are from papers, journals and magazines as referenced in each example.
Electrical Failure | Power Steering Failure | Flu in Winter | Zebra Stripes | Antibiotic Drugs | Pangaea | Didymo | Bird Plumage | Hummingbirds
A caller said that after a big rain storm, the car would start okay, but none of the electrical devices (radio, fan, etc.) would work. When the car dried out everything worked again. Two theories were mentioned by the hosts: fuses and the ignition switch. A distinction was made between the lock, where the key is placed, and the ignition switch which is separate from the lock and controls all of the electrical devices (except the lights). The driver has a number of keys on their key ring. The driver only experienced it three times but always after a rain storm. It rains a lot where this happens. The hosts predicted that jiggling the keys would cause the electrical devices to function properly.
The observation is that something is causing the electrical devices to fail.
There were three theories posed:A1: The rain caused the electrical devices to fail.
A2: A faulty fuse caused the electrical devices to fail.
A3: A faulty ignition switch caused the electrical devices to fail.For our purposes in this example we will assume that all three theories have merit (normally they would be evaluated in terms of the criteria for a scientific theory previously enumerated).
The first theory, however, doesn't have a clear connection to the electrical devices not working. The fact that it rains a lot there suggests that the probability of this happening after a rain storm is high independently of anything else and may not have any bearing on the failure of the electrical devices. It was categorized on the show as a "red herring". That eliminates any data connecting rain to the electrical failure and leaves two theories to consider.
D1: The failure only happened three times (it is sporadic).D2: The driver has a number of keys (the weight of the keys could cause the key to move inside of the ignition switch).
Ignition Switch Fuse Sporadic yes no Heavy Keys yes no
Given this data (ignition - 2, fuse - 0), the ignition switch is most likely to be the culprit.
The caller stated that, if the air conditioner was on when going around a curve, sometimes the power steering would fail. It has never done it when the air conditioner is off. It happens three out of five times when the air conditioner is on. The air conditioner works perfectly without any noise, etc. The first time it happened the car was loaded down. The caller thought it might have been the extra weight, but the next time it happened only two passengers were in the car. There was a discussion suggesting that the compressor might be faulty. This model of car only has one belt. A slipping belt could cause this problem. The belt could slip if it didn't have the correct tension, so it was proposed that the tensioner, a device to keep the belt tension constant, was faulty. A faulty tensioner would not be noticed under normal conditions. The belt had been changed but it didn't fix the problem.
The initial observation is that something is causing the power steering to fail.
Two theories were proposed by the hosts:
- A faulty compressor causing an additional load (which would cause stress on the belt). (A1)
- A faulty belt tensioner (a device to keep the belt at a particular tension). (A2)
Again assume that the criteria for a scientific theory, as previously presented, have been met. The preliminary conditions are then satisfied since either of these conditions could cause the belt to slip and the power steering to fail. Note that one theory, more weight would put stress on the compressor, was discarded, in a sense, by a single "no". The observation that the power steering failed with less weight was so important that the theory was summarily discarded.
- Fails 3 out of 5 times (sporadic). (D1)
- Doesn't do it when the AC is off. (D2)
- Happens when going around curves. (D3)
- Air conditioner works perfectly. (D4)
- Faulty tensioner would not be noticed under normal conditions. (D5)
- Changing the belt did not help. (D6)
Tensioner Compressor Sporadic yes no Only when AC is on no yes Curves yes no AC works well no no Normal Conditions yes no Changing Belt yes yes
Given this data (tensioner - 4, Compressor - 2), the tensioner theory would be the most likely to be true.
An article on 1 April 2014 was published in the journal Nature about the function of zebra stripes (a new window will open). The magazine Science News provides a nice summary of the article. Use the password getting2Zarticle to read the summary of the article jotting down the theories proposed and the data that is given for the function of zebra stripes. In addition to the theories proposed in the articles there was a comment posted suggesting that there is evidence that the stripes have been present from the beginning.
After reading the article and the accompanying comment, develop an abduction outline, including an evaluation chart, and then see my analysis.
Another research article was published in January of 2015 in Royal Society Open Science with some more data that may be of interest. They seem to think that the cooling (thermoregulation) theory very likely explains the purpose of the stripes. It would be interesting to do an abduction outline just from the data in this article. It would also be interesting to combine the two research articles and see if it changes the abduction outline results.
Yet another summary article was published in February of 2016 in Science News with some more information that may be of interest.
On 20 February 2019 The New York Times published and an article about zebra stripes and flies that supports our findings.
How Antibiotic Drugs Work
In the 3 May 2014 issue of the magazine Science News an article, explaining two theories about how antibiotic drugs work, was published. Use the password getting2Aarticle to read the article jotting down the theories proposed and the data that is given for the functioning of antibiotics. After reading the article and the accompanying comment, develop an abduction outline, including an evaluation chart, and then see my analysis.
The Breaking Up of Pangaea
In a Science News article (The password is getting2Pangaea) on March 8, 2015 Thomas Sumner wrote about research that sheds new light on the splitting up of Pangaea. "The current prevailing explanation contends that material from the Earth’s interior sprung up along the boundary between North America and Africa, forcing the two continents apart." He also explains that: "A reexamination of tectonic movements 200 million years ago suggests that the supercontinent was pulled apart by shrinking of the forerunner to the modern Indian Ocean." My abduciton outline.
An interesting article about getting the flu in the 5 December 2007 New York Times article by Gina Kolata (a new window will open). You will be asked to write an abduction outline as Homework #8 (see the homework page for more information). I will send my analysis to you with the graded homework. Another related New York Times article titled "Can Being Cold Make You Sick?" by Karen Weintraub dated Feb. 23, 2018 may be interesting as well. In 2022 CNN published an article called "Scientists finally know why people get more colds and flu in winter" online at https://www.cnn.com/2022/12/06/health/why-winter-colds-flu-wellness/index.html. The study that was referenced stated that dropping the temperature in your nose by nine degrees "cuts your immune system’s ability to fight off respiratory infections by half." The article explains why. This new theory should be added to our analysis.
Didymo Blooms
In the 21 May 2014 online issue of the magazine Science News an article was published proposing two theories about how didymo blooms are formed. Use the password getting2Darticle to read the article. You will be asked to write a full abduction outline from this article in Homework #9 (see the homework page for more information). My analysis will be included in the graded homework.
Bird Plumage
On 27 March 2015 an article appeared in Science Advances (SA) about the bright plumage of birds. A summary of the article is found in Science News (SN). An example of a possible abduction outline from the Science Advances article is given in my analysis.
Hummingbirds
In the 18 August 2015 an article appeared in the online issue of the magazine Science News proposing two theories about how hummingbirds drink nector. The prevailing theory is that they use capillary action to draw the nector up into their mouth. The "crazy idea" theory says that the tongue acts like a little pump to move the nector up into their mouth. Use the password getting2Hummingbird to read the whole article. Here is my abduction outline taken from this article