PrepTest 124, Section 2, Question 13
Researcher: People with certain personality disorders have more(36 more words not shown)
A questionable aspect of the(5 more words not shown)
- Auses the phrase(3 more words not shown)
- Bfails to define(5 more words not shown)
- Ctakes correlation to(4 more words not shown)
- Ddraws a conclusion(6 more words not shown)
- Einfers that watching(8 more words not shown)
Reading the argument
Which way does the connection run?
People with these disorders have more theta brain waves. That doesn't tell us that the waves cause the disorders. Perhaps the disorders produce the extra waves. Perhaps some other underlying condition produces both. The fact that the two occur together leaves those possibilities open.
Now add the finding that theta waves increase while someone watches TV. Even accepting that TV increases those waves, we still haven't established that increasing the waves creates a personality disorder. The argument needs that missing step to move from watching TV to a greater risk of a disorder.
What we’re looking for
So my prediction for the flaw is straightforward: the researcher treats an observed association as a causal connection. We don't need to know the detailed science of theta waves to see the problem. We need to know what relationship the evidence establishes, and what stronger relationship the conclusion requires.
Working the answers
- A
The argument doesn't change the meaning of 'personality disorders.' Not listing the particular disorders isn't the same as using the phrase in two different senses. A real meaning change would be like moving from cranes that are birds to cranes used for construction. Nothing like that happens here.
- B
A technical term can be used consistently without a full scientific definition. We're told the relevant relationships: more theta waves accompany the disorders, and the waves increase during TV viewing. Defining the waves would not by itself establish that they cause the disorders. That's the missing information that matters.
- CCorrect
The researcher relies on theta waves causing personality disorders, but the first sentence only associates them. If the disorder produces the extra waves instead, raising the waves through some other activity wouldn't necessarily create the disorder. The conclusion needs a causal link that the stated evidence hasn't established.
- D
We haven't been told anything that makes the sample unrepresentative. If the researcher studied only the researcher's own children, we'd have a concrete reason to question generalizing from that group. Here, inventing a bad sample would add a problem rather than identify one shown in the argument. We can see the causal gap without making that assumption.
- E
This reverses the conclusion. The researcher claims that watching TV increases the risk of a personality disorder, not that a disorder causes someone to watch TV. Be careful to identify the argument the researcher actually makes, even when another causal direction is worth considering.
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