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November 15th, 2009 (Permalink)

The Puzzle of the Terrorist Acquaintance

The Agency for Counter-Terrorism (ACT) comes to you with a logical problem. The agency has information on four subjects, one of whom is known to be a terrorist. To protect the innocent, we will refer to them as Subjects 1 through 4.

Subject 1 is the known terrorist. Subject 1 is acquainted with Subject 2. Subject 2 has met Subject 3, therefore they are acquainted. Subject 3 was observed talking to Subject 4, so they're also acquainted. Subject 4 is known not to be a terrorist. It's not known whether Subjects 2 and 3 are terrorists or not.

ACT wants to know: among the four subjects, is a terrorist acquainted with a non-terrorist? Choose an answer:

  1. Yes.
  2. No.
  3. There is not enough information to determine whether a terrorist and a non-terrorist are acquainted.

Solution

Acknowledgment: Thanks to Vasilios Magriplis for pointing out a typographical error in the original wording of the puzzle that has now been corrected.

November 11th, 2009 (Permalink)

Are you intelligent but irrational?

Test yourself with an article in the latest issue of Scientific American Mind on the difference between intelligence and rationality by psychologist Keith Stanovich. It contains a number of puzzles that may make you feel foolish, but don't feel too bad if you get a wrong answer: you're in good company. Regular readers of The Fallacy Files should recognize the Wason selection task and a puzzle based on the base rate fallacy, and I hope would not be fooled by them.

I've known a lot of highly intelligent people, including some much smarter than I am. However, some of them were perplexingly irrational, at least about some things. I used to be very puzzled by this, until I drew a distinction between intelligence/stupidity on one hand, and wisdom/foolishness on the other. It's perfectly possible to be an intelligent fool: I've known a few! It may even be possible to be a wise idiot, though I've never actually met one. However, the point is that raw intelligence and rationality don't always go hand-in-hand. Intelligence is innate, but rationality must be cultivated.

The article is based on Stanovich's book What Intelligence Tests Miss: The Psychology of Rational Thought, which I would love to receive a review copy of.

Source: Keith E. Stanovich, "Rational and Irrational Thought: The Thinking That IQ Tests Miss", Scientific American Mind, 11/2009

November 8th, 2009 (Permalink)

New Books: Denialism and Unscientific America

Continuing the twin themes of "where's the harm?" and weird science, here's a couple of new books: Chris Mooney and Sheril Kirshenbaum's Unscientific America and Michael Specter's Denialism. Both appear to deal with the widespread scientific illiteracy that helps lead to the harm that I've noted in previous entries. For instance, the quantum quackery practiced by James Arthur Ray is made possible by the fact that so many people have no idea what quantum mechanics is all about, and can't tell the difference between the real thing and bafflegab. You don't have to be a physicist to be able to tell that Rhonda Byrne doesn't know what she's talking about; you just need to be scientifically literate. I haven't done a book club in a long time, and it's possible that one or both of these books might make good material. As always, it would be nice if someone would send me review copies.

Books:

  • Chris Mooney & Sheril Kirshenbaum, Unscientific America: How Scientific Illiteracy Threatens our Future (2009)
  • Michael Specter, Denialism: How Irrational Thinking Hinders Scientific Progress, Harms the Planet, and Threatens Our Lives (2009)

Weird Science
November 6th, 2009 (Permalink)

Where's the Harm?


  • (11/7/2009) Also here:
    Despite major bombings that have rattled the nation, … Iraq’s security forces have been relying on a device to detect bombs and weapons that … technical experts say is useless. … The small hand-held wand, with a telescopic antenna on a swivel, is being used at hundreds of checkpoints in Iraq. But…a retired United States Air Force officer, Lt. Col. Hal Bidlack,…described the wand as nothing more than an explosives divining rod. … The suicide bombers who managed to get two tons of explosives into downtown Baghdad on Oct. 25, killing 155 people and destroying three ministries, had to pass at least one checkpoint where [it] is typically deployed,….

    The Iraqis have spent 85 million dollars on these pieces of junk. If you want a dowsing rod, you can make one yourself from the branch of a willow tree, or from a wire coat hanger. However, you won't be able to detect explosives with it any better than by flipping a coin, and people will be blown up as a result, but at least you won't be wasting millions of dollars. Apparently, for less than 5 million dollars they could equip every checkpoint in Baghdad with a bomb-sniffing dog.

    Dale Murray, head of the the National Explosive Engineering Sciences Security Center at Sandia Labs, which does testing for the Department of Defense, said the center had "tested several devices in this category, and none have ever performed better than random chance." … The Justice Department has warned against buying a variety of products that claim to detect explosives at a distance with a portable device. … "I don’t care about Sandia or the Department of Justice or any of them," General Jabiri said. "I know more about this issue than the Americans do. In fact, I know more about bombs than anyone in the world." He attributed the decrease in bombings in Baghdad since 2007 to the use of the wands at checkpoints.

    It's time to play name that fallacy! For the answer, see below.

    If, as often happens, no explosives or weapons are found, the police may blame a false positive on other things found in the car, like perfume, air fresheners or gold fillings in the driver’s teeth. … During an interview on Tuesday, General Jabiri challenged a Times reporter to test [it], placing a grenade and a machine pistol in plain view in his office. Despite two attempts, the wand did not detect the weapons when used by the reporter but did so each time it was used by a policeman. "You need more training," the general said.

    This kind of excuse-making by ad hoc hypothesis is a standard feature of pseudoscience: a hit is counted as a hit, but a miss is not counted as a miss―instead, it's excused and explained away. Every "psychic" detective does the same thing by throwing out lots of information about where a missing person will be found, then counting only the hits and ignoring the misses. With this kind of scoring system, you can't lose!

    That's why it's necessary to test dowsing and "psychics" in such a way that all the hits and misses are counted. When that is done, dowsers do no better than chance. Of course, the dowsers always have explanations for their failures: conditions weren't right, something was interfering with their powers, the tests were rigged against them, etc. Similarly, the General―whose idea it was for an untrained reporter to test the device!―excuses its failure as due to the reporter's lack of training.

    The Iraqis could do just as well by using some kind of randomizer at checkpoints to pick out cars for searches as they can with these high-priced dowsing rods.

    Source: Rod Nordland, "Iraq Swears by Bomb Detector U.S. Sees as Useless", The New York Times, 11/3/2009

    Fallacy: Post Hoc

    Acknowledgment: Thanks to Vance Ricks for calling this to my attention.

  • Here it is:
    The shortage of swine-flu vaccine results not from drug- company greed or outsize demand but almost entirely from the government's decision to pander to unfounded and unscientific fear. As The Wall Street Journal reported last week, the US government set out to have the H1N1 vaccine produced largely in single-dose syringes―a demand that has set back production considerably, because multidose vials are far easier to make. And the only reason to seek single-dose production was to please people needlessly worried about the preservative thimerasol, which is used to provide multiple doses of the vaccine. The fear―utterly groundless and repeatedly debunked is that thimerasol can cause autism and other neurological disorders in infants and other young children. If not for that decision, we'd have more than enough vaccine. Instead, because the government yielded to pressure from antivaccine fringe groups, we're behind the curve on protecting millions of children from swine flu.

    So, some children will get the flu and some may even die from it because of fallacious fears that vaccines caused other children's autism. It's hard to say how much blame for this should fall on celebrities such as Jenny McCarthy and Bill Maher, but it's definitely nonzero. Of course, as much or more blame must fall on those who listened to these celebrities and took their silly advice seriously.

    Sources:

    Resources:

November 1st, 2009 (Permalink)

What's New?

The Multiple Comparisons Fallacy. I haven't added it to the Taxonomy yet; that is to come. As usual, if you notice any errors or omissions, please let me know.

General Hooker Entrance
October 28th, 2009 (Permalink)

Check it Out, Too

Britain's Guardian newspaper has a fascinating history of the birth and growth over the last ten years of the estimate of the number of prostitutes trafficked into the U.K.

The number started small but grew with every step of its spread. This is similar to the old game of "telephone", in which a message is whispered into the ear of a person at the front of a line, who then whispers it to the next person in line, and so on to the end of the line. The point of the game is that the message at the end is very different than the original message, being distorted in the process of transmission. However, one difference in this case is that there seems to have been a definite bias to the distortion. If the distortions were simply due to random errors of transmission, one would expect there to be as many errors tending to diminish the number as to increase it, but that's not what happened.

What could explain this kind of statistical inflation? Suppose that each person in the game of telephone has a motive to exaggerate the number they hear. Interest groups have an interest in using big numbers to raise awareness of a problem, and raise money to deal with it; news media have an interest in using big numbers to get bigger ratings or sell more newspapers and magazines; politicians have an interest in using big numbers to get votes and pass legislation. Unfortunately, few players of the game are strongly motivated to get the numbers right. To quote the Numbers Guy:

…[W]ith sensitive issues such as this one, it can be hard to find voices on the other side; after all, no one who wants accurate numbers wants to be seen as supporting sex trafficking.

Read the whole thing.

Sources:

UP TO $1,000 TRADE-IN FOR YOUR OLD SOFA
October 25th, 2009 (Permalink)

Always Read the Fine Print

Ben Goldacre's latest Bad Science column deals with a slanted debate about a slanted movie:

You may remember the Aids denialist documentary House Of Numbers…a film which suggests that HIV doesn’t cause Aids, but antiretroviral drugs do, or poverty, or drug use, but HIV probably doesn’t exist, diagnostic tools don’t work, and Aids is simply a spurious basket diagnosis invented to sell antiretroviral medication for a wide range of unrelated problems, and the treatments don’t work either. …

Christine Maggiore appears many times in the film, talking emotively, explaining her choice not to take Aids medication, and that this is why she is alive.

Christine Maggiore is dead…. The film tells you that but in tiny letters at the very end and it says no more. She died of pneumonia aged 52. And her daughter died of untreated Aids aged 3. Because of her beliefs about Aids, Christine Maggiore did not take medication which has been proven to reduce the risk of HIV transmission to her unborn child during pregnancy. Her daughter, Eliza Jane, was not tested for HIV during her short life. Before she died. Of Aids.

Check it out.

Sources:

October 24th, 2009 (Permalink)

Q&A

Q: I've been hearing this sort of argument made recently by right-wing pundits:

Obama is a good speaker.
Hitler is a good speaker.
[More or less implied conclusion:] Obama is Hitler (or like Hitler).

The same type of argument might be made in regard to other characteristics:

Obama wants to nationalize big business.
Hitler nationalized big business.
Therefore, Obama is like Hitler.

I realize that these are not quite genuine formal syllogisms, and I realize that the first example depends on opinion (perhaps some think Obama or Hitler are not good speakers) and that the second example contains untrue premises (Hitler did not nationalize big business; Obama does not want to nationalize big business), but, regardless, some people are making these sorts of arguments anyway.

My question, however, is not whether or not these arguments are valid (I know they are not), but, rather, my question is, what is the name of this sort of fallacy?

The closest type I have been able to identify is the Fallacy of the Undistributed Middle. It doesn't quite fit the above examples, however, because the Fallacy of the Undistributed Middle seems to rely on the word "All," in which case the following would be a better example of the Fallacy of the Undistributed Middle:

Obama is a good speaker.
All Nazis are good speakers.
Therefore, Obama is a Nazi.

Clearly, this is an example of the Fallacy of the Undistributed Middle.

But what about the first two examples I gave you? Are they, too, Fallacies of the Undistributed Middle; or are they some other type of fallacy (and if so, which)? Or are they merely badly written?―Shane K. Bernard

A: It's better to view these arguments not as categorical syllogisms, but as arguments by analogy, that is, arguments whose premisses state that two things are alike in certain respects, and which conclude that they will be alike in some other respects. Analogical arguments are inductive, rather than deductive like categorical syllogisms. Analogical arguments are fallacious when the analogy drawn is either weak, superficial, or question-begging.

More specifically, this is a version of the Hitler Card argument which draws a comparison between someone and Hitler. It appears that we live in a political and rhetorical environment where every president of the United States will sooner or later―probably sooner―be compared to Hitler. During the previous presidency there were many claims that Bush was a would-be Hitler, and I documented a few of the more outrageous and ridiculous ones on this weblog (see the Resources below).

Of course, Obama is a good speaker. Bush had his moments too, though he was poor at speaking extemporaneously, as is Obama. However, anyone who rises to our highest political office is very likely to be an effective speaker, so to that extent every president will have something in common with Hitler. Moreover, if you go searching for similarities between any two people, you're bound to find some.

So, it's just about inevitable that Obama will come in for his share of abuse, and the only real change will be in where the abuse is coming from. It would be nice if the political right would not copy the left's bad behavior toward the previous president, but it's more likely that they will think that turnabout is fair play, even though two wrongs don't make a right. Then, of course, the left will take their revenge on the next Republican president, and so on ad nauseum.

I suppose that it's also expecting too much, now that Bush has left the presidency, to hope that some of those who made the Bush-Hitler linkage would admit that they were wrong. Why didn't he declare martial law? Why didn't he suspend the election? Why didn't he make himself into the dictator that they seemed to think he wanted to be? If Bush was a wannabe dictator, he was a poor one.

Resources:

October 21st, 2009 (Permalink)

In the Mail

David B. Grant's Joseph Spider and the Fallacy Farm.

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