LSAT 105 | Section 1 | Logical Reasoning: Q4

LR Question 4 Explanation

QUESTION TEXT: In an experiment testing whether hyperactivity …

QUESTION TYPE: Weaken

CONCLUSION: Diminished activity in the premotor cortex is one cause of hyperactivity.

REASONING: In a study, hyperactive adults had less activity in the premotor cortex than nonhyperactive adults.

ANALYSIS: There are some flaws you should train yourself to spot immediately. This is one of them. Causation versus correlation is a classic flaw that comes up decently often.

Just because hyperactive individuals have lower premotor cortex activity does not mean this causes hyperactivity. You should look for an answer choice that weakens this alleged causal link. Maybe there’s a third factor that causes both hyperactivity and lower cortex activity? Or maybe it’s actually the reverse – hyperactivity decreases premotor cortex activity.

___________

1. This implies that genetics may play a role, but it doesn’t directly undermine the causal conclusion that the stimulus draws.
2. That’s normal. Usually any group of individuals who experience an illness will have a range of symptoms that differ in severity. How does this affect the stimulus? (It doesn’t.)
3. This is getting at ideas relating to experimental design. But we need something that undermines that lower premotor cortex activity ➞ hyperactivity. Besides, we don’t know whether it’s a good or bad thing that the neuropsychologists weren’t present.
4. CORRECT. Exactly. The lower cortex activity is actually the result of being treated for hyperactivity. So it only came after the fact, meaning it couldn’t have caused hyperactivity itself.
5. The reason for testing only adults doesn’t weaken the reasoning. It might limit how applicable these findings are to children, but that has no effect on the argument.