Logical reasoning PrepTest 158 · Section 4 · Question 14

This doesn't address the conclusion's claim that the increase in blood pressure is caused by the stress of speaking and not by the physical exertion required to speak. It just shows that medications do not completely eliminate the increase in blood pressure. If the answer choice said that people who take medications that lower stress do not experience blood pressure increases while speaking, it would be an example of "no cause, no effect" and would strengthen the argument. But this answer choice does not say that, so we can confidently eliminate it.

This answer choice is tempting to some because it affirms the relationship between stress and blood pressure increases. It suggests that stress increases blood pressure. However, that does not necessarily support the argument's conclusion that increased blood pressure while speaking results from the stress of speaking. Stress may increase one's blood pressure, but that doesn't mean people get stressed enough while speaking to have their blood pressure increase.

This answer choice also doesn't strengthen the belief that increased blood pressure while speaking does not result from the physical exertion required to speak. Even if stress increases one's blood pressure, the physical act of speaking could increase one's blood pressure, too. So, this answer choice allows for the physical act of speaking to increase people's blood pressure.

Finally, this answer choice states that there's a relationship between one's baseline blood pressure and the amount their blood pressure will increase. However, the argument doesn't compare people with low blood pressure to people with high blood pressure. It compares extroverts to introverts. So, the relationship this answer choice describes is not relevant to the researcher's argument.

This is the most popular wrong answer choice. It's understandable that many test-takers are attracted to this answer choice since it affirms a relationship between introverts and increased blood pressure that the researcher's argument discusses. In a way, this answer choice resembles "same cause, same effect."

However, there are a few issues with this answer choice. First, even if introverts "often sense" that their blood pressure increases while speaking, it doesn't necessarily mean that their blood pressure is actually increasing. And even if their blood pressure is increasing, that doesn't mean their blood pressure is increasing because they're stressed. Their blood pressure might rise from the physical act of speaking or for some other reason.

Additionally, this answer choice discusses introverts "who do not have chronically high blood pressure." But the researcher's argument doesn't compare people with chronically high blood pressure to those with average or below-average blood pressure. It compares extroverts to introverts. So, it's unclear why information about introverts who don't have chronically high blood pressure is relevant to the researcher's argument.

Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen

Passage Summary:
Talking usually increases one's blood pressure. Talking increases extroverted people's blood pressure less than introverted people's. Talking is more stressful for introverted people. So, the stress of speaking causes an increase in blood pressure; the physical exertion required to speak does not cause the increase.

Strategy Overview:

1. Argument or facts? Always argument, so identify premises and conclusions of argument
2. Anticipate why the premises are not enough to show that the conclusion is true
1. Causal argument? Look for answer choice that:
1. Rules out possible alternate cause
2. Shows same cause, same effect
3. Shows no cause, no effect
4. Shows the cause and effect are not reversed
3. If not causal argument, anticipate ways to fix problem with argument
4. Use anticipations to select the answer choice that, if true, would strengthen argument

Answer Anticipation:
On Strengthen questions, the correct answer usually helps fix a flaw in the argument. This is why we should try to identify a problem with the argument first. Once we identify the problem, we're better equipped to pick an answer choice that fixes that problem.

Causation flaws are among the more common on Strengthen (and Weaken!) questions, and this is undoubtedly a causal argument: the stress of speaking causes an increase in blood pressure ("result from" is our causal indicator word here). This is also an anti-causal argument; it concludes that the physical exertion required to speak does not cause an increase in blood pressure. We'll return to this anti-causal claim in just a moment. Let's first focus on the causal claim.

Once we've identified the causal claim in this argument, we can anticipate a few ways the correct answer may strengthen it. The passage mentioned a possible alternate cause (the physical exertion required to speak), so the correct answer might further rule out physical exertion as the culprit. Although the passage already provided examples of "same cause, same effect" (introverts are more stressed when they speak, and their blood pressure increases more), the correct answer could provide another example. Another likely possibility is providing an instance of "no cause, no effect," particularly because the passage hasn't already provided such an example. The correct answer may show that when people do not try to communicate (for instance, when they make nonsense sounds), they do not feel stressed and their blood pressure does not increase.

It's also worth mentioning that the correct answer could strengthen this argument by weakening the anti-causal claim. The author asserts that the physical exertion of speaking does not cause an increase in blood pressure. An answer choice could show that this physical act by itself is not enough to raise blood pressure. In effect, this would probably resemble the example of "no cause, no effect" discussed above. The correct answer might show that when people exert themselves to make sounds but do not attempt to speak, they do not experience increased blood pressure.

Answer Choice Explanation:
It is exceedingly unlikely that you anticipated that the correct answer would discuss deaf people. In fact, many test-takers dismiss this answer choice out of hand, figuring that deaf people are irrelevant to the researcher's argument. But, before we do that, we should consider whether this argument presents one of the causal argument strengtheners we look for (elimination of an alternative cause; same cause, same effect; no cause, no effect).

This tells us that deaf people experience increased blood pressure when they sign. Signing is how deaf people communicate, and we have no reason to believe that deaf people do not experience the same "psychological stress of communicating" that non-deaf people experience while speaking. So, if deaf people's blood pressure increases while experiencing the psychological stress of communicating, this answer choice presents an example of "same cause, same effect." It affirms the relationship between the stress of communication and increased blood pressure.

This answer choice also tells us that deaf people's blood pressure does not increase while moving their hands for other reasons. If a deaf person moves their hand for reasons other than signing, they're not experiencing the "psychological stress of communicating." There's no stress and no corresponding increase in heart rate. Therefore, this answer choice also presents an example of "no cause, no effect." If we take away the stress of communicating, we take away increased blood pressure.

This last point is the most salient one. Remember, the researcher asserts that the physical exertion required to speak does not cause an increase in blood pressure. However, it would be difficult for the researcher to test that conclusion with people who communicate vocally. When these people speak, they will always feel the stress of communication and physically exert themselves. It would be hard for the researcher to isolate one of those variables with vocal communicators. But deaf people (or anyone else who communicates through non-vocal means) provide a way to isolate one of these variables. Deaf people do not experience the physical exertion required to speak. If their blood pressure still increases when they communicate, that suggests that the increase is due to the stress of communication and not the physical exertion required to speak.

In a way, we can think of this answer choice as strengthening the researcher's anti-causal claim. In other words, the answer choice strengthens the argument by weakening the causal relationship between physical exertion and increased blood pressure. This answer choice provides an example of "effect without the cause" — deaf people do not experience the physical exertion required to speak while communicating, but their blood pressure increases all the same.

This answer choice is far from perfect. It would more clearly strengthen the argument if we knew that introverted deaf people's blood pressure increased more while signing than extroverted deaf people's. But, this answer still provides strong examples of "same cause, same effect" and "no cause, no effect," so we can mark it as a contender. If we can eliminate (E), we can confidently select (D).

Key Takeaway:
Strengthen and Weaken questions are far from the "opposites" their names may imply. In fact, the strategies used for each overlap significantly. When an author claims that a cause-and-effect relationship doesn't exist on a Strengthen question, we can look for an answer choice that weakens that cause-and-effect relationship. Here, the correct answer strengthens the researcher's argument that the physical exertion required to speak does not cause an increase in blood pressure. The correct answer does so by weakening the causal relationship between physical exertion and increased blood pressure. The correct answer provides an example of "effect without the cause." Deaf people do not experience the physical exertion required to speak while communicating, but their blood pressure nonetheless increases.

This answer choice weakens the argument, as it provides an alternative reason why extroverts experience "milder surges" in their blood pressure while speaking. This answer choice suggests that these milder surges are not because extroverted people are less likely to feel stressed while communicating — it could be because extroverts are more likely to be on medication that suppresses their blood pressure.