LSAT Question Explanation
PT 105, Section 1, Question 4
WeakenArgument structure
Diminished activity in the premotor cortex is one cause of hyperactivity.
The hyperactive adults in the study had less brain activity in the premotor cortex.
Explanation
This is a weaken question, so we need to look for flaws in the argument. The flaw here is classic for the stimulus of a weaken question: correlation vs causation!
We know that in the study lower premotor cortex activity was somehow associated with hyperactivity, but we can't claim any causal relationship. In the answer choices I'll be looking for something that reverses the supposed cause and effect, introduces a different cause, or shows the supposed cause without the effect or supposed effect without the cause.
Answer choices
This doesn't address how hyperactivity relates to the premotor cortex.
The subjects with hyperactivity had way lower premotor cortex activity than the subjects who were not hyperactive... this answer choice doesn't change that.
This is trying to trick you into thinking the study was flawed, but I don't see why this would invalidate the results. There could have been other highly competent researchers present.
Aha! This tells us that the lower premotor cortex activity may have been caused by a drug that was given after the adults were diagnosed as hyperactive. This casts a lot of doubt on the idea from the conclusion that the low premotor cortex activity caused the hyperactivity.
This doesn't tell us anything about the relationship between hyperactivity and the premotor cortex.