In an experiment testing whether hyperactivity is due to a brain abnormality, the brain activity of 25 hyperactive adults was compared to the brain activity of 25 adults who were not hyperactive. The tests revealed that the hyperactive adults had much less brain activity in the premotor cortex, a region of the brain believed to control action, than did the non-hyperactive adults. The experimenters concluded that diminished activity in the premotor cortex is one cause of hyperactivity.

Which one of the following, if true, most undermines the conclusion drawn by the experimenters?

Answer Choices

Correct answer marked below

Some of the non-hyperactive adults in the study had children who suffer from hyperactivity.

The hyperactive adults who participated in the experiment varied in the severity of their symptoms.

The neuropsychologists who designed the experiment were not present when the tests were performed.

All of the hyperactive adults in the study had been treated for hyperactivity with a medication that is known to depress activity in some regions of the brain, while none of the non-hyperactive adults had been so treated.

Correct

The test was performed only on adults because even though the method by which the test measured brain activity is harmless to adults, it does require the use of radiation, which could be harmful to children.

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What this question tests

What it tests

Whether you can identify the option that most undermines an argument's conclusion.

Common trap

Choosing an irrelevant objection or one that attacks the premise rather than the reasoning.