LSAT 134 | Section 2 | Logical Reasoning: Q2

LR Question 2 Explanation

QUESTION TEXT: Psychologist: A study of 436 university students …

QUESTION TYPE: Flawed Reasoning

CONCLUSION: Napping probably causes insomnia.

REASONING: University students who nap more often have higher rates of insomnia. Commercial fishers also nap frequently and also have high rates of insomnia.

ANALYSIS: The psychologist notices a correlation:

• Frequent nappers are more likely to have insomnia.
• Another group that naps frequently also has lots of insomnia.

Then concludes that napping probably causes insomnia.

The problem is that the evidence only shows that napping and insomnia occur together. It doesn’t tell us which one causes the other.

A perfectly reasonable alternative is that people with insomnia often can’t get enough sleep at night, so they compensate by taking naps during the day. In that case, insomnia would cause napping. Not the other way around like the argument claims.

Btw, if you haven’t trained yourself to recognize correlation-causation flaws immediately, you should practice it. They come up decently often on the LSAT.

___________

1. The argument never compares university students to the general population. That comparison isn’t needed.
2. The psychologist only argues that napping tends to cause insomnia. Nothing requires all insomnia to have one cause.
3. The exact definition of “napping” isn’t the issue. It’s used consistently throughout the argument.
4. CORRECT. Maybe people nap because they have insomnia, not the other way around. The argument never rules out this possibility.
5. The psychologist explicitly says fishing-vessel workers have irregular sleep patterns. This answer misstates the argument.