Logical reasoning PrepTest 118 · Section 3 · Question 15

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Bizarro Errors in Reasoning

Stimulus Summary:
Most insomnia cases treated by psychologists are due to stress, so insomniacs should have psychotherapy, not drugs that change brain chemistry, and thus doctors shouldn't prescribe sedatives to insomniacs.

Answer Anticipation:
A Bizarro Errors in Reasoning question? Think about what that means—there are at least four flaws in this argument! As such, we should identify a few of them, but we absolutely need to remain flexible as we head to the answers, as it's unlikely we'll spot them all.

So digging in, let's take a look. First, the premise is about "[m]ost" cases of insomnia but the conclusion is that doctors should "never" prescribe sedatives. That premise is weaker than the conclusion so there's one flaw—it's possible the minority of cases not discussed should be treated with sedatives.

Second the cases discussed are those that psychologists treat so it's possible that cases of insomnia that are treated by other doctors should be treated with sedatives.

Third the argument brings up the cause of insomnia in these cases—stress—to rule out the use of sedatives but it's possible that these sedatives should be used to address this cause.

We've looked at each statement and identified something wrong with it—we have three flaws we can look for. We definitely need to stay flexible then as there's at least one more flaw that can show up in the answers!

Answer Explanation:
This answer deals with an assumption of causality between insomnia (cause) and stress (effect). However the stimulus establishes that stress causes insomnia ("are known to be caused by") so it doesn't assume the opposite relationship. Since this answer brings up an assumption the argument doesn't make it's the correct answer in this Bizarro question.

Key Takeaway:
As we move into the harder questions in the section the wrong answers end up being closer to the right ones. And that gets flipped around in a Bizarro question where the right answer isn't clearly out of scope or outlandish. Here the correct answer dealt with causality—and the stimulus also brought up causal relationships. It was necessary to dig into the details to analyze that answer and see that it didn't apply. Be aware of where in the section you are so you can shift your mindset towards the answer choices! An answer that seems clearly wrong in question #1 likely is; an answer that seems clearly wrong in question #16 might be a well—hidden right answer!

Incorrect. This answer highlights that the stimulus discusses only a subset of cases of insomnia, and so there might be others that would be best treated with sedatives, undermining the conclusion that these drugs should never be used.

Incorrect. This answer highlights that psychotherapy might not treat the stress causing insomnia in all cases, and so sedatives might need to be prescribed in those cases.

Incorrect. The Psychologist assumes that psychotherapy is the treatment for stress—related insomnia, ignoring the possibility that sedatives might be just as (or even more) effective.

Incorrect. The Psychologist limits her discussion of insomnia cases to those treated by psychologists, overlooking cases treated by other doctors. As such, she's ignoring a whole area of cases that might be best treated with sedatives.