Answer: C. It draws a conclusion about a causal relationship between two phenomena from evidence that merely suggests that there is a correlation between those phenomena.
Explanation:
Understanding the Argument:
• Premise: A study of 1,000 adults found that those who ate the most chocolate were the most likely to feel depressed.
• Conclusion: Reducing excessive chocolate consumption will almost certainly improve adults’ mood.
The argument assumes a causal relationship between eating chocolate and depression. However, the study provides evidence only of a correlation between chocolate consumption and depression, not causation.
Analyzing the Answer Choices:
• (A): It improperly infers from the fact that a substance causally contributes to a condition that a reduction in the consumption of the substance is likely to eliminate that condition.
• The argument does not establish a causal link between chocolate consumption and depression in the first place. Instead, it assumes causation from correlation, which makes this option incorrect.
• (B): It draws a conclusion about the population as a whole on the basis of a sample that is unlikely to be representative of that population.
• There is no evidence in the passage to suggest that the sample is unrepresentative. The argument relies on a potentially flawed assumption about causation, not the representativeness of the sample.
• (C): It draws a conclusion about a causal relationship between two phenomena from evidence that merely suggests that there is a correlation between those phenomena.
• Correct. This accurately describes the flaw. The argument assumes that eating chocolate causes depression, but the evidence only suggests a correlation, not causation. Other explanations for the correlation, such as depressed individuals eating more chocolate, are ignored.
• (D): It confuses a condition that is necessary for establishing the truth of the conclusion with a condition that is sufficient for establishing the truth of the conclusion.
• This describes a different type of reasoning flaw. The argument does not depend on a necessary/sufficient condition confusion.
• (E): Its conclusion is worded too vaguely to evaluate the degree to which the premises support the truth of the conclusion.
• The conclusion is not vague; it clearly states that reducing chocolate consumption will “almost certainly” improve mood. The issue lies in the assumption of causation, not in the vagueness of the conclusion.
Conclusion:
The argument’s main flaw is assuming a causal relationship between chocolate consumption and depression based on evidence of correlation. Therefore, option C is the correct answer.