Passage Summary: Scientists use brain scans to study thinking, but they can't really make sense of the data unless the people being scanned are telling the truth about what's on their minds.

Conclusion: Researchers must be able to trust the accuracy of what subjects say they are thinking while being scanned if they want to understand how the brain facilitates thought.

Reasoning: Without accurate verbal reports, researchers cannot be sure if the brain activity they see corresponds to the specific thoughts the subject claims to have.

Analysis: In this 'Identify the Conclusion' task, the word 'however' serves as a major structural signpost, pivoting from the background information about brain scans to the author's main point. The final sentence provides the justification for this point by explaining the negative consequences of inaccurate reports. When looking for the correct answer, prioritize the statement that expresses this central requirement for research. Avoid choices that focus on the technical details of the brain scans themselves, as those are merely supporting premises.