Logical Reasoning

PT158 · S4 · Q14 Psychologist: Most people's blood

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Psychologist: Most people's blood pressure rises when they talk.

Conclusion

The psychological stress, not the physiological exertion, involved in talking causes one's blood pressure to rise.

Evidence

Most people's blood pressure rises somewhat when they talk, but introverted people's BP rises even more than extroverted people's, and introverted people are more psychologically stressed when they're talking.

Evaluate

The author is presenting a correlation, more psychologically || higher blood stressed (introverts) pressure rises

Then, like so many brave LSAT authors before her, she assumes that one of those things causes the other.

She thinks that the extra stress is causing the extra blood pressure spike.

We always confront these Curious Fact → Causal Explanation arguments with the same two concerns: 1. Alternate Explanation for the curious fact 2. plausibility of the Author's Explanation

Goal

Since this is Strengthen, we want to either

rule out an alternate explanation for the correlation - f.e., it's not the case that having higher blood pressure is actually causing the extroverted people to feel more stress

increase the plausibility of the Author's Explanation - f.e. when people go from speaking in a more stressful to a less stressful setting, their blood pressure usually falls

14.

Which one of the following, if true, most strengthens the psychologist's argument?

Medications designed to lower blood
No Impact
Whether medications can control BP fluctuations during speech tells us about treatment, not causation. The argument needs to distinguish between two possible causes — physical exertion and psychological stress. Medication effectiveness is irrelevant to that distinction. Even if no medication could prevent the BP rise, that would not tell us whether the rise is caused by muscle movement or anxiety. And even if medications could prevent it, that still would not identify the cause. Cause and treatment are different questions.
9% picked this
In general, the lower one's
No Impact
Information about the relationship between typical blood pressure levels and stress-induced increases does not distinguish between the two competing explanations (physical exertion vs. psychological stress). Whether people with lower baseline BP show bigger increases under stress is a general physiological fact that applies regardless of the cause of the stress. The argument needs evidence that specifically isolates communication as the variable — not general information about BP reactivity patterns. This answer addresses the magnitude of BP changes, not their cause.
4% picked this
Introverted people who do not
No Impact
Whether introverts can sense their own BP rising tells us about self-perception, not about what causes the rise. Awareness of a physiological response is unrelated to the mechanism producing it. An introvert could feel their BP rising and still have no idea whether the cause is physical exertion, psychological stress, or something else entirely. The argument needs evidence that separates the physical and psychological components of speaking — not evidence about whether people can detect their own physiological changes.
22% picked this
Correct
Deaf people experience increased blood
Why this is right
This evidence creates a beautifully controlled natural experiment. Deaf people who use sign language provide a unique test case: signing involves hand and arm movements (physical exertion), and so do many non-communicative hand activities. If BP rises during signing (communication) but not during other comparable hand movements (non-communicative physical exertion), then physical effort alone cannot explain the BP increase. The physical variable — hand/arm movement — is held roughly constant. The communication variable changes: signing involves communicating with another person, while other hand movements do not. The different BP outcomes across these conditions directly isolate communication as the causal factor. This eliminates the alternative explanation (physical exertion) while supporting the argument's conclusion (psychological stress of communication). It is the gold standard of strengthening evidence: a natural experiment that controls for the confounding variable.
Skill tested: Strengthen · how this choice captures the argument's function is the move to repeat next time.
63% picked this
Extroverted people are more likely
Weakens, if Anything
The argument relies on the introvert/extrovert difference to support its stress-based explanation: introverts find communication more stressful and show bigger BP spikes. If extroverts — who supposedly experience less communication stress — are actually more prone to chronically high BP, this complicates the argument's reasoning. It suggests that personality-based BP patterns may not track neatly with communication stress levels, introducing a confounding variable that muddies the argument's clean story about stress and BP. Rather than strengthening the communication-stress explanation, this information weakens it by suggesting the relationship between personality traits and BP is more complex than the argument assumes.
2% picked this

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