Logical reasoning PrepTest 132 · Section 4 · Question 22

Incorrect. Without tying this into the group discussed in the stimulus—the children, and in particular, the younger children—this answer doesn't strengthen the argument.

Incorrect. This answer suggests an alternative cause—the children that are more likely to get allergies are eating foods that cause allergic reactions. If it's the diet and not the exposure to germs that accounts for the incidence of allergies, then the argument is weakened.

Incorrect. While this answer might recommend intentionally exposing your children to germs to stop them from getting allergies if the connection in the stimulus exists, it does nothing to strengthen the connection between germs and allergies.

Incorrect. This answer choice brings up an alternative potential cause of allergies—genes—and thus weakens the argument.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Strengthen

Stimulus Summary:
Phenomenon—Children in large families (particularly the youngest) have fewer allergies
Explanation—Exposure to germs in infancy reduces risk of allergies

Answer Anticipation:
This argument has three features that suggest a certain flaw and, thus, a certain answer.

First, it brings up a phenomenon and then tries to explain it with a hypothesis. This type of argument generally is flawed in that it ignores alternative explanations.

Second, the argument is causal. While it's phrased in the negative, it's essentially saying that exposure to germs causes you to have a lower risk of allergies. This is based on a correlation, so the argument has a correlation/causation flaw.

Third, there's a brand new term in the conclusion—germs. There's no indication that those in larger families are exposed to more germs, so that's a jump that the argument makes.

The first two considerations are very much linked—alternative explanations and alternative causes are, in this case, the same thing. So one potential area for a correct answer will be our common Strengthen answers:

(1) Eliminate an alternative cause/explanation
(2) Find more examples of cause and effect together
(3) Control group—no cause, no effect (but this is already hinted at in the stimulus by comparing the rate of allergies in different family sizes)
(4) Explain how the causality works

For the term shift, a correct answer would simply establish the connection.

Answer Explanation:
This answer establishes that children in smaller families that are exposed to more children—making them similar to younger siblings in other families—are less likely to have allergies. By introducing a way that a subset of children in smaller families are similar to those in larger families, and showing this subset is similar in the incidence of allergies, the connection there is strengthened and the argument is stronger for it. Another way of looking at it? It shows that the children in smaller families that have a similar cause as the one hypothesized also have a similar effect.

Key Takeaway:
Hypotheses are meant to explain phenomenon. As such, they serve as explanations, and they're almost always causal explanations. When you see a causal hypothesis in a Strengthen question, start to look for answers that fit into our regular patterns for correlation/causation flaws.