Logical reasoning PrepTest 113 · Section 4 · Question 2

Question prompt

The vomeronasal organ (VNO) Remaining source text redacted.
Why the credited answer is right

Credited answer: A

The notes below walk through why it fits the stem and how to eliminate the rest.

Argument or Facts

Argument

Valid or Flawed

Flawed

Question Type

Weaken Questions

Stimulus Summary

Science.
Study - Stimulating the VNO in humans resulted in them smelling things
Conclusion - The VNO works in humans

Answer Anticipation

This is a pretty complicated argument for question #2! Let’s ignore the science and unpack it.
First, science passages frequently deal in causality - it’s what science is all about. And research/studies frequently find correlations that are used to back up that causality. So we should start by considering a Correlation/Causation flaw - especially since that’s the most common flaw in Weaken questions.
Here, the study found that when the VNO cells in humans were stimulated, people reported smelling things. While that can feel causal, it’s actually a correlation - the language doesn’t say that the stimulation caused the smells. It’s possible that something the researchers did triggered something other than the VNOs to make people believe they were smelling things.
The conclusion itself isn’t causal, but it has a causal assumption. To conclude that the VNOs are working, it must be assumed that the smell sensation was caused by the VNO stimulation. Since this argument jumps from a correlation to causation, we can weaken it using the normal weakeners:
Identify an alternative cause (this is similar to what we said in the last paragraph) Counterexamples (VNO stimulation without smell sensations; smell sensations without VNO stimulation wouldn’t work here as there’s no indication that only VNOs can detect smells) Reversed causality (this doesn’t make sense, as the research says the stimulation came before reporting smells)

Answer choices

  1. A
    It is not known Remaining source text redacted.
    Why choice A matches the stem
    This answer hints at a potential alternative cause. If the stimulation of the VNO cells may have also stimulated other cells, those cells could be responsible for the smell sensation. Since this answer raises an alternative possibility, it weakens the argument and is correct.
  2. B
    Relative to its occurrence Remaining source text redacted.
    Why choice B is not credited
    There’s no indication that the VNO needs to be particularly sophisticated to detect smells, so the human VNO being underdeveloped doesn’t affect the causality in the argument.
  3. C
    Certain chemicals that play Remaining source text redacted.
    Why choice C is not credited
    What matters isn’t how the VNO works but whether it works. Additionally, there’s no indication that this organ is used by animals to detect smells, so it’s not clear if a difference between human and other animal VNO would be a problem!
  4. D
    Secondary anatomical structures associated Remaining source text redacted.
    Why choice D is not credited
    The secondary organs aren’t tied to smell, so this answer has no effect on the argument.
  5. E
    For many animal species, Remaining source text redacted.
    Why choice E is not credited
    If anything, this strengthens the argument by relating the VNO to smelling things.

What this tests

Question analytics

Based on historical answer selection rates for this question.

Answer choice distribution

  1. A Credited 76%
  2. B 6%
  3. C 10%
  4. D 5%
  5. E 4%

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