Question

A large group of hyperactive children whose regular diets included food containing large amounts of additives was observed by researchers trained to assess the presence or absence of behavior problems. The children were then placed on a low-additive diet for several weeks, after which they were observed again. Originally nearly 60 percent of the children exhibited behavior problems; after the change in diet, only 30 percent did so. On the basis of these data, it can be concluded that food additives can contribute to behavior problems in hyperactive children. The evidence cited fails to establish the conclusion because (A) there is no evidence that the reduction in behavior problems was proportionate to the reduction in food-additive intake (B) there is no way to know what changes would have occurred without the change of diet, since only children who changed to a low-additive diet were studied (C) exactly how many children exhibited behavior problems after the change in diet cannot be determined, since the size of the group studied is not precisely given (D) there is no evidence that the behavior of some of the children was unaffected by additives (E) the evidence is consistent with the claim that some children exhibit more frequent behavior problems after being on the low-additive diet than they had exhibited when first observed

Short answer

Correct answer is (B): No control group to measure diet change effects.

Step-by-step solution

Understanding the Conclusion

The conclusion of the argument states that the reduction in observed behavior problems among hyperactive children was due to the decrease in food additives in their diet. This suggests a causal relationship based on the evidence presented.

Identifying the Evidence

The evidence presented is the observation that behavior problems reduced from 60% to 30% after a dietary change to low-additive foods. This data implies a link between food additives and behavior problems but does not establish a direct causal relationship.

Analyzing the Critical Point

The task requires identifying why the evidence does not conclusively support the conclusion. Consider whether other factors could contribute to behavior changes, or if there are gaps in the evidence provided.

Evaluating Each Option

- Option (A) questions the proportionate reduction but acknowledges some change. - Option (B) highlights the lack of a control group or alternative scenario, crucial for causal inference. - Option (C) focuses on an unknown group size, which does not affect the causation directly. - Option (D) suggests a possibility of unaffected children, which doesn't directly attack the conclusion. - Option (E) proposes an inconsistency but doesn't directly address causal inference.

Identifying the Correct Answer

The key is whether the study's design allows for a clear causal conclusion about the effect of food additives. Option (B) identifies the fundamental flaw: without a control group, it's impossible to discern whether the observed change in behavior was truly due to the diet change or other factors.

Key concepts

Causal Reasoning

Causal reasoning is a method used to establish a cause-and-effect relationship. In the context of this exercise, it refers to determining if the reduction in behavior problems among hyperactive children was actually caused by the dietary change to low-additive foods. The research observed a decrease from 60% to 30% in behavior issues after changing the diet, which initially suggests a causal link between food additives and behavior problems.

To strengthen causal reasoning, researchers often look for:

• Correlation: Does the change in diet correlate with the reduction in behavior problems?
• Elimination of other variables: Are there other factors that might have influenced behavior changes?
• Replication: Can the findings be replicated in other settings or studies?

Without ruling out other variables or having a control group, the conclusion made by the researchers could be premature. It’s possible that other factors, like natural maturation over time or changes in other environmental variables, could have contributed to the observed outcome.

Critical Thinking

Critical thinking involves analyzing information and arguments in a logical and disciplined way. In this exercise, it includes questioning the conclusion drawn by the researchers that food additives contribute to behavior problems in hyperactive children. By engaging in critical thinking, one should evaluate whether the evidence sufficiently supports this conclusion.

When assessing claims critically, consider:

• Assumptions: Are there any unstated assumptions influencing the conclusion?
• Quality of evidence: Is the evidence provided robust and appropriately collected?
• Validity: Is there a logical connection between evidence and conclusion?

Applying critical thinking means not accepting conclusions at face value but instead analyzing the strength of the reasons and evidence provided.

Argument Evaluation

Argument evaluation is about assessing the components that make up an argument to understand its validity and reliability. In the research regarding hyperactive children's diet, the main argument is that food additives cause behavior problems. Evaluating this claim involves dissecting the structure as follows:

• Premises: The reduction in behavior problems after reducing food additives serves as the main premise.
• Conclusion: The argument concludes that food additives are linked to behavior issues.
• Validity: Consider if the premises logically lead to the conclusion.
• Soundness: Evaluate if the premises are true and if the argument overall is persuasive.

By examining the premises and determining whether they adequately support the conclusion, one can critique the strength of the argument. This evaluation reveals whether the research has accounted for all necessary variables to reliably attribute behavior changes to dietary changes.

Research Methodology

Research methodology refers to the systematic plan followed in conducting the study. It includes the design, collection, analysis, and interpretation of data. In the case of this study, the methodology involves observing changes in behavior following a dietary shift to low-additive foods.

Important elements of research methodology include:

• Design: Consider whether the study used a control group and how it was structured.
• Data Collection: How was data gathered, and was it consistently applied across all participants?
• Analysis: Was the data analyzed correctly to truly reflect changes attributed to diet?
• Conclusion: Does the methodology lead to a reliable conclusion without leaving significant gaps?

The lack of a control group in this study is a major flaw, as it prevents distinguishing whether improvements are due to the diet or other unaccounted factors, thus affecting the research's validity. Ensuring a robust research methodology is critical for drawing accurate conclusions from the data.