Passage Summary: People who take naps seem to have more trouble sleeping at night. Because these two things happen together, the author assumes the naps are the reason for the sleep trouble.

Conclusion: Napping is likely the cause of insomnia.

Reasoning: There is a correlation between napping and insomnia observed in both university students and commercial fishing vessel workers.

Analysis: This argument falls into the 'Correlation vs. Causation' trap, which is a favorite of the LSAT. The psychologist observes that two things happen at the same time and jumps to the conclusion that one must be causing the other. Look for an answer that suggests the relationship could be reversed—perhaps insomnia causes people to be so tired that they *must* nap—or that a third factor, like a stressful lifestyle, causes both. In logic, 'togetherness' does not equal 'influence.'