Although migraine headaches are believed to be caused by food allergies, putting patients on diets that eliminate those foods to...
GMAT Critical Reasoning : (CR) Questions
Although migraine headaches are believed to be caused by food allergies, putting patients on diets that eliminate those foods to which the patients have been demonstrated to have allergic migraine reactions frequently does not stop headaches. Obviously, some other cause of migraine headaches besides food allergies must exist.
Which of the following, if true, would most weaken the conclusion above?
Passage Analysis:
| Text from Passage | Analysis |
|---|---|
| Although migraine headaches are believed to be caused by food allergies, putting patients on diets that eliminate those foods to which the patients have been demonstrated to have allergic migraine reactions frequently does not stop headaches. |
|
| Obviously, some other cause of migraine headaches besides food allergies must exist. |
|
Argument Flow:
The argument starts with a common belief (food allergies cause migraines), then presents evidence that challenges this belief (elimination diets don't always work), and concludes that there must be other causes beyond food allergies
Main Conclusion:
Some other cause of migraine headaches besides food allergies must exist
Logical Structure:
This is a classic 'elimination of alternatives' argument. The author assumes that if food allergies were the only cause, then removing them should always stop migraines. Since this doesn't happen, the author concludes other causes must exist. The logic depends on the assumption that successful treatment should eliminate the problem completely
Prethinking:
Question type:
Weaken - We need to find information that would reduce our belief in the conclusion that 'some other cause of migraine headaches besides food allergies must exist'
Precision of Claims
The key claim is about causation - the author concludes there MUST be other causes beyond food allergies. The evidence shows elimination diets 'frequently' don't work, meaning most of the time but not necessarily always.
Strategy
To weaken this conclusion, we need to show that food allergies could still be the primary or only cause, even though elimination diets frequently fail. We should look for reasons why removing allergic foods might not work even if food allergies are the true cause. This means finding alternative explanations for why the treatment fails without requiring additional causes.
Many common foods elicit an allergic response only after several days, making it very difficult to observe links between specific foods patients eat and headaches they develop.
This choice provides a compelling alternative explanation for why elimination diets fail. If allergic reactions to foods occur several days after consumption, it becomes extremely difficult to connect specific foods to specific headache episodes. This means patients and doctors might identify the wrong foods as triggers and eliminate the wrong items from diets. Even if food allergies are the only cause of migraines, the treatment would still fail because we're eliminating the wrong foods. This directly weakens the conclusion by showing that treatment failure doesn't necessarily mean other causes exist - it could just mean we're treating the problem incorrectly.
Food allergies affect many people who never develop the symptom of migraine headaches.
This choice tells us that many people with food allergies don't get migraines. However, this doesn't weaken the argument at all. The author isn't claiming that all food allergies cause migraines, just that food allergies can cause migraines in some people. The fact that not everyone with food allergies gets migraines is completely consistent with the argument and doesn't address why elimination diets fail in migraine sufferers.
Many patients report that the foods that cause them migraine headaches are among the foods that they most enjoy eating.
This choice about patients enjoying the foods that trigger their migraines is irrelevant to the logical structure of the argument. Whether patients like or dislike their trigger foods doesn't explain why elimination diets frequently fail or provide any alternative explanation for the treatment failure. It doesn't address the core issue of causation at all.
Very few patients have allergic migraine reactions as children and then live migraine-free adult lives once they have eliminated from their diets foods to which they have been demonstrated to be allergic.
This choice actually strengthens rather than weakens the argument. If very few patients live migraine-free lives after eliminating allergic foods, this supports the idea that other causes beyond food allergies must exist. This makes the conclusion more likely to be true, which is the opposite of what we want in a weaken question.
Very rarely do food allergies cause patients to suffer a symptom more severe than that of migraine headaches.
This choice about the severity of symptoms relative to other food allergy symptoms is completely irrelevant. Whether migraines are more or less severe than other allergic reactions has no bearing on whether food allergies are the only cause of migraines or why elimination diets might fail. It's a classic irrelevant comparison that doesn't address the argument's logic.