Which of the following, if true, casts the most serious doubt on the researchers’ interpretation of their findings?
- The researchers’ view does little more than echo a familiar theme in folklore and literature.
- Clinically depressed individuals are no less careful than others to follow a healthy lifestyle.
- Disorders of the immune system cause many of those individuals who have them to become clinically depressed.
- Individuals who have previously been free from depression can become depressed quite suddenly.
- A high frequency of autoimmune disorders can stem from an unusually high level of exposure to stress.
Question type: Weaken
Difficulty level: Medium
Summary of the argument: Being clinically depressed makes people more likely to develop autoimmune disorders; this is based on the correlation found in the study.
- This is irrelevant and not true based on the argument.
- This actually strengthens the argument by removing an alternate cause.
- This is correct as it shows a reverse causation. Perhaps people with autoimmune disorders are more likely to develop depression and not the other way round.
- This does not relate to the context of autoimmune disorders.
- “Stress” is vague and out of scope.