Among people who experience migraine headaches, some experience what doctors call "common" migraines, whereas others experience "classical" migraines....
GMAT Critical Reasoning : (CR) Questions
Among people who experience migraine headaches, some experience what doctors call "common" migraines, whereas others experience "classical" migraines. Siblings and spouses of common migraine sufferers are themselves twice as likely as the general population to experience common migraines. Siblings of classical migraine sufferers are four times more likely than the general population to experience classical migraines, whereas spouses of classical migraine sufferers are no more likely than the general population to experience such headaches.
The information above provides the most support for which of the following hypotheses?
Passage Visualization
| Passage Statement | Visualization and Linkage |
|---|---|
| "Among people who experience migraine headaches, some experience what doctors call 'common' migraines, whereas others experience 'classical' migraines." | Establishes: Two distinct types of migraines
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| "Siblings and spouses of common migraine sufferers are themselves twice as likely as the general population to experience common migraines." | Pattern for Common Migraines:
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| "Siblings of classical migraine sufferers are four times more likely than the general population to experience classical migraines" | Siblings Pattern for Classical:
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| "whereas spouses of classical migraine sufferers are no more likely than the general population to experience such headaches." | Spouses Pattern for Classical:
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| Overall Implication | The passage reveals two fundamentally different transmission patterns:
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Valid Inferences
Inference: Classical migraines have a stronger genetic component than common migraines, while common migraines involve environmental factors that classical migraines do not.
Supporting Logic: Since siblings of classical migraine sufferers show a 4x increased risk while spouses show no increased risk, classical migraines follow a purely genetic transmission pattern. Since both siblings and spouses of common migraine sufferers show identical 2x increased risk, common migraines must involve environmental or lifestyle factors in addition to genetic predisposition. Therefore, the two migraine types have fundamentally different underlying transmission mechanisms.
Clarification Note: The passage supports conclusions about transmission patterns but does not reveal the specific genetic or environmental mechanisms involved. We cannot determine whether common migraines are less genetic or simply involve additional environmental triggers.
This choice states that classical migraines depend more on hereditary factors than common migraines. The passage strongly supports this - classical migraines show a pure genetic pattern (siblings \(4\times\) risk, spouses no increased risk) while common migraines show mixed transmission (both siblings and spouses \(2\times\) risk). The absence of spouse transmission for classical migraines versus its presence for common migraines clearly indicates classical migraines are more genetically dependent. This is CORRECT.
This claims unmarried adults are more likely to suffer classical than common migraines. The passage provides no information about marital status affecting migraine type prevalence. We only know about transmission patterns within families, not about baseline rates between married and unmarried populations. This goes beyond what we can infer.
This suggests people without migraines are unlikely to have migraine-suffering spouses. The passage tells us spouses of classical migraine sufferers have normal population risk, and spouses of common migraine sufferers have \(2\times\) risk, but this doesn't allow us to work backwards and determine the likelihood that non-sufferers have migraine-suffering spouses. This reverses the logical direction inappropriately.
This states children of common migraine sufferers are more likely than the general population to experience common migraines. While this seems reasonable given that siblings show \(2\times\) risk, the passage specifically mentions 'siblings' not 'children.' We can't assume sibling data applies to parent-child relationships without additional information. This makes an unjustified leap from sibling data.
This claims \(25\text{-}50\%\) of the general population suffers from migraines. The passage provides relative risk data (\(2\times\), \(4\times\) increases) but gives us no baseline rates for the general population. We cannot calculate absolute prevalence from relative risk information alone. This requires data not provided in the passage.