PrepTest 130, Section 1, Question 11
Recent studies indicate a correlation between damage to(54 more words not shown)
Which one of the following(10 more words not shown)
- AThe argument ignores(17 more words not shown)
- BThe argument presumes,(11 more words not shown)
- CThe argument makes(8 more words not shown)
- DThe argument mistakes(5 more words not shown)
- EThe argument presumes,(7 more words not shown)
Reading the argument
A correlation tells us that two things tend to occur together. It doesn't, by itself, settle whether one causes the other. So when the passage begins with chromosome damage and schizophrenia, I'm waiting to see what causal claim the author makes.
The argument takes an unexpected direction. Some people develop schizophrenia without the chromosome damage, and some people with the damage don't develop schizophrenia. From those exceptions, the author concludes that there is no causal connection at all.
That goes too far. Imagine arguing that smoking can't cause lung cancer because some nonsmokers develop lung cancer and some smokers don't. Those exceptions wouldn't eliminate a causal contribution. A cause needn't be the only cause of an outcome, and it needn't produce that outcome in everyone exposed to it.
What we’re looking for
The flaw question asks us to identify what the argument overlooks. I'd look for a way a causal relationship could still exist despite the exceptions. We don't have to establish the actual cause of schizophrenia to show that the author's dismissal is unsupported.
Working the answers
- ACorrect
The different types of damage could have different effects. Imagine, just to make the distinction concrete, that damage to one part of chromosome six could lead to schizophrenia while damage to another part did not. People in the second group would provide exceptions without disproving the effect in the first. And schizophrenia in people without this chromosome damage could have another cause. A gives a specific way the exceptions could coexist with a causal connection.
- B
The argument doesn't claim that chromosomal damage is the sole cause. It concludes that there is no causal connection between damage to chromosome six and schizophrenia. B attributes a positive causal claim to an argument that rejects one.
- C
Studies are mentioned, but nothing indicates that their participants were unrepresentative. We can accept the reported correlation and exceptions and still identify the flaw: those exceptions don't rule out all causation. We don't need to invent a sampling defect.
- D
Mistaking a cause for an effect would involve assigning the causal relationship the wrong direction. The author doesn't say schizophrenia causes the damage or that the damage causes schizophrenia. The author denies a causal connection altogether.
- E
This is the mistake we might have anticipated from the opening correlation, but it isn't the argument we received. The author rejects causation rather than inferring it from correlation. Keep the criticism tied to the actual conclusion.
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