CR:Galanin in rats

[tak2pratik]

Source: Powerscore CR Bible

Galanin is a protein found in the brain. In an experiment, rats that consistently chose to eat fatty foods when offered a choice between lean and fatty foods were found to have significantly higher concentrations of galanin in their brains than did rats that consistently chose lean over fatty foods. These facts strongly support the conclusion that galanin causes rats to crave fatty foods.

Which one of the following, if true, most supports the argument?
(A) The craving for fatty foods does not invariably result in a rat's choosing those foods over lean foods.
(B) The brains of the rats that consistently chose to eat fatty foods did not contain significantly more fat than did the brains of rats that consistently chose lean foods.
(C) The chemical components of galanin are present in both fatty foods and lean foods.
(D) The rats that preferred fatty foods had the higher concentrations of galanin in their brains before they were offered fatty foods.
(E) Rats that metabolize fat less efficiently than do other rats develop high concentrations of galanin in their brains.

Please explain why the OA is D. Also,an explanation as to how the other options can be eliminated will prove helpful.

[tim]

ideally this should have been written as an assumption question. this is a classic example of a models of causation problem. researchers notice a protein correlates with a food preference, and they assert that the protein causes the food preference. the correct answer for a problem of this type should eliminate the possibility that the food preference caused the protein. this is what D does here..

[ShriramC110]

Hi Ron/Tim,

This is a type of causality question, in which A --> B( Galatanin leads to Craving Fatty Foods)
We can normally stenghten the causal arguements by eliminating any alternate cause.Right?
In this Case , if we consider the option choice A, then tht choice eliminates the alternate cause that (Any other thing doesn't doesn't cause rats to crave food other than Galatanin).
Am i Right??

Thanks

[RonPurewal]

hm...

well, you don't need to worry about choice A, because choice A is completely ridiculous. in the real world, here on planet earth, it makes no sense at all.

just think about it for a sec:

• if a rat feels 'cravings', then, obviously, there is no way for the rat to communicate those feelings to humans. (rats do not speak human languages.)

• thus, in any research conducted by human beings, any such 'craving' must be defined by the rat's actual food choices.
i.e., if a rat actually chooses fatty foods over other foods, then we say the rat is 'craving' fatty foods.

• choice A posits a conflict between the rat's 'cravings' and its actual behavior—like the kind of austere self-denial practiced by dieters, athletes, and monks.
even if rats were capable of this sort of cognitive dissonance (an idea that's already ... um ... ambitious), we humans wouldn't be able to tell—we'd just see the rat NOT eating fatty foods, and so we'd label that behavior as 'not craving fatty foods'.

in other words, the whole existence of choice A depends on human researchers' ability to detect when rats' actions are at odds with their feelings/emotions.
thus choice A is, in practical terms, impossible to realize.
thus choice A is silly nonsense.
thus choice A can be disregarded, because it does not resemble anything that you will ever see on the official exam.

the official exam will NEVER EVER contain an answer option that is silly/fatuous/impracticable/farfetched/absurd/impossible.
if you see any such thing in a third-party resource, simply ignore it.