PrepTest 114

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen

Stimulus Summary:
Study:
(1) Over a 6—month period with an earthquake at the 3—month mark, students in California and Ontario recorded their dreams
(2) California students — After the earthquake, over half reported earthquake dreams
(3) Ontario students — Most never experienced earthquakes, and almost none reported dreaming of earthquakes
Conclusion — Experiencing an earthquake can cause earthquake dreams

Answer Anticipation:
Strengthen questions frequently feature correlation/causation flaws, and arguments based on studies frequently feature correlation/causation flaws and sampling flaws. Let's start by considering those two flaws since we have specific ways to strengthen arguments that commit them!

Let's start with the sampling flaw, because there's an interesting reason that we can rule this out as a potential correct answer. The conclusion here is that experiencing an earthquake can cause earthquake dreams. Since that's stated as a potential outcome, it doesn't need to be shown that it happens in the general population, but rather just that it happens for some people. As such, showing that it happens in students or those who live in California would be enough to justify the conclusion.

Now, on to the correlation/causation flaw. The conclusion is causal—explicitly so! And it is based on a correlation between experiencing an earthquake and earthquake dreams. Interestingly, it also throws in a control group for us in the form of the Ontario students—a group that didn't experience the supposed cause and also didn't experience the effect! That would normally be a way to strengthen an argument with a correlation/causation flaw. When we look to strengthen an argument with a correlation/causation flaw, we generally do so by:
(1) Eliminating an alternative cause
(2) Finding more examples of the cause and effect going together
(3) Establish a "control" group—a situation where the cause was absent and so was the effect

As we said the stimulus presents a control group but there's actually a conspicuous piece of information missing from the timeline—what were the California students's dreams like before the earthquake? The argument relies on the high frequency of earthquake dreams after the earthquake to show that it caused the dreams but it doesn't establish that the California students had a low level of earthquake dreams before the earthquake. This would be another type of control—showing that the Californians didn't experience the effect before they experienced the cause. Let's find that answer.

Answer Explanation:
This answer establishes that before the supposed cause happened for the California group they also lacked the effect. Then once they experienced the earthquake they started having earthquake dreams. This strengthens the correlation between the event and the dreams by showing that they started at around the same time thus strengthening the causal argument.

Key Takeaway:
Sampling flaws are unlikely to be relevant in an argument that concludes one thing can cause another as any example of that relationship holding true—even if only in a small subset of the population—would support that conclusion. Also timelines are always important on the LSAT and that's especially true for causality as the supposed cause should happen before but around the same time as the effect.

Incorrect. There's no indication that the purpose behind recording the dreams is relevant to the content of those dreams, so this answer is out of scope.

Incorrect. If anything, this answer weakens the argument by showing that the supposed cause—experiencing an earthquake—was present before the earthquake dreams started showing up.

Incorrect. The number of dreams overall isn't relevant—just the number of earthquake dreams. There might be an answer similar to this that could be correct if it brought up the percentage of the California students's dreams that were earthquake related, but it doesn't do so here.

Incorrect. The supposed cause from the stimulus is "experiencing" an earthquake not an earthquake happening. This answer doesn't provide any indication that the students in Ontario were visiting California during the earthquake so it doesn't provide more correlation. And if anything it might hint at an alternative cause—not experiencing an earthquake but hearing about one on the news.