Logical Reasoning

PT113 · S4 · Q13 When several of a dermatologist’s

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When several of a dermatologist’s patients complained of a rash on just one side of their faces, the dermatologist suspected that the cause was some kind of external contact.

Conclusion

The one-sided facial rash was caused by prolonged contact with telephones.

Evidence

Several patients had a rash on just one side of their faces, and in each case the rash was on the same side as the patient's telephone use.

Evaluate

When we're dealing with a "diagnosis / hypothesis / explanation", we know we're dealing with Explain Curious Fact.

CURIOUS FACT: Why do these patients have a rash on one side of their face?

EXPLANATION: It's caused by prolonged contact with telephones.

Whenever we're dealing with this template, we know we can strengthen by 1. ruling out an Alternate Explanation for the curious fact 2. making the Author's Explanation more plausible

Goal

We need to get rid of four answers that strengthen. Typically, with EXCEPT questions, three of those four will do it one way and the other one will do it a different way.

So we might get three answers making the phone hypothesis more plausible and one answer ruling out the idea that the rash comes from something else (e.g. the side of their face that lays on their pillow at night).

The correct answer will either weaken or be irrelevant.

13.

Each of the following, if true, provides additional support for the dermatologist's diagnosis EXCEPT:

  1. Many telephones are now manufactured

    Strengthens

    This boosts the plausibility of the phone hypothesis by talking about the "causal mechanism". How would a phone cause a rash? Phones are made with a plastic some people are allergic to.

    2% picked this

  2. Contact between other devices and

    Strengthens

    This rules out alternate explanations. If the rash were caused by some other device these people were using, we'd expect to see the rash on both sides of their face, since the other devices contact both sides of their face equally.

    37% picked this

  3. Most of the patients had

    Strengthens

    This makes the phone hypothesis more plausible by putting the suspect "prolonged phone contact" at the scene of the crime. In order to believe that prolonged phone contact is the culprit, we need to know that these people have prolonged contact with phones, and this answer establishes that assumption, which strengthens.

    1% picked this

  4. Correct

    Telephones are used by most

    Why this is right

    This just has no impact. It doesn't make it more likely that the phone caused the rash (do most people in the industrialized world have a rash on one side of their face?) And it doesn't rule out any alternate explanation.

    Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.

    60% picked this

  5. The complaints occurred after an

    Strengthens

    This adds plausibility to the phone hypothesis by adding a time dimension to it. The rash started showing up right after an increase in phone use. That looks pretty suspicious, pretty incriminating that prolonged phone use had something to do with the rash.

    0% picked this

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