Passage Summary: Scientists found that people's moods match up with which side of their brain is more active, so they have concluded that the brain activity is what causes the mood.

Conclusion: A person's general mood or disposition is caused by the activity levels in their frontal lobe.

Reasoning: Research indicates a correlation where depressed individuals show less left frontal lobe activity, whereas good-natured individuals show more.

Analysis: This argument commits a classic causal fallacy by assuming that because two things happen together, one must cause the other. In this case, the author observes a correlation between brain activity and mood and concludes that the brain activity is the driver. To weaken this, one might suggest that the mood actually causes the brain activity, or that a third factor influences both. Since this is a 'Weaken EXCEPT' question, look for the one answer choice that does not disrupt this causal link or is simply irrelevant to the relationship.