Logical reasoning PrepTest 149 · Section 4 · Question 7

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Errors in Reasoning

Stimulus Summary:
Watching funny videos was correlated with stronger immune systems, so laughter helps people get better. However, the effect was bigger in people who tend to laugh, so those people will benefit more from funny videos even if they laugh less at them than those who tend not to laugh who laugh more at the videos.

Answer Anticipation:
This argument starts off with a traditional correlation/causation flaw, but it pivots away from it to another argument about the connection between other elements—the tendency to laugh and the actual amount laughed.

Looking at that second part of the argument, it uses another correlation—the immune system gains were higher for those with a higher tendency to laugh—and it then shifts the causation from the initial section of the argument, treating that tendency as the real cause of the immune system gains. We can tell because the conclusion of the argument downplays the amount of laughter as the relevant cause and focuses on the tendency to laugh—hence the conclusion that those with a tendency to laugh will see more help in their recovery, even when they laugh less.

Yes, it's all a bit confusing, but we can reframe this in a much simpler manner. The argument starts by stating that laughter helps people recover more quickly, but then it brings up an alternative cause that it treats as leading to both things—laughter and recovery. It's a tendency to laugh that causes both laughter and recovery.

That's a big jump, though! Even though those with a tendency to laugh tended to see a greater immune system boost, they'd also be the ones who are laughing more—so the amount of laughter would also be positively correlated with that immune system boost. The pivot here brings up an argument that applies equally well to the original cause being the true cause—laughter helping people recover. The correct answer will likely highlight that the information presented is just as supportive of the initial cause—laughter—as the revised cause—tendency to laugh, even if that person laughs less.

Answer Explanation:
This answer highlights the possibility that the argument overlooks—that those with a greater tendency to laugh also laughed more at the videos, and so the laughter itself was also positively correlated with healing. In highlighting that the evidence supports the initial cause as much as the revised cause as the true cause, this answer highlights a flaw in the argument.

Key Takeaway:
Whenever an argument itself raises a potential alternative cause, there's a good chance that the correct answer will highlight it. Here, the stimulus noted that the laughter itself could be a cause of the recovery, but it then jumped to saying that the tendency to laugh was the real determinative factor. The correct answer jumped back to evidence that the laughter itself was the true cause.

Incorrect. The premises all indicate immune systems that grew stronger—a relative term that takes into account starting conditions. Since these starting conditions were taken into account, the argument doesn't fail to address this possibility. If the stimulus compared the immune systems between patients instead of looking before and after in the same patient, then this answer would be correct.

Incorrect. The conclusion is just that laughter/a tendency to laugh can aid in recovery from illness, so it only has to be true in some cases to hold. Even if the hospital patients aren't representative of the overall population, they're still a population that can justify the conclusion.

Incorrect. This answer is bringing up the possibility of reversed causality. However, in this case, the stimulus specifically notes a timeline—the comic videos were watched, then the immune system got stronger—so reversed causality can't be applied to it.

Incorrect. The stimulus establishes that those with a tendency to laugh had greater gains in immune system strength, thus aiding in recovery.