V06-31

Official Solution:


Aldolase is a protein found in the brain. In an experiment, subjects who consistently chose sweetened drinks when offered a choice between salty and sweetened drinks were found to have significantly higher concentrations of Aldolase in their brains than did subjects who consistently chose salty drinks over sweetened drinks. This observation strongly supports the conclusion that Aldolase causes subjects to crave sweetened drinks.

Which one of the following, if true, supports the argument the most?


A. The craving for sweetened drinks does not invariably result in choosing those drinks over salty drinks.
B. The brains of the subjects that consistently chose to drink sweetened drinks did not contain significantly higher concentrations of another chemical, which is found to cause cravings for sweet food among mice, than did the brains of subjects that consistently chose salty drinks.
C. The chemical components of Aldolase are present in both sweetened and salty drinks.
D. Concentrations of Aldolase detected in the brain are significantly higher after taking sweet beverages than those detected before.
E. Subjects that metabolize sugar less efficiently than do other subjects develop high concentrations of Aldolase in their brains.


Premise: Correlation is seen between choosing sweetened drinks and higher concentrations of Aldolase.

Conclusion: Aldolase causes cravings for sweetened drinks.

A. The premise deals with a relation between Aldolase and choosing sweetened drinks. The conclusion is about a relation between Aldolase and craving for sweetened drinks. The missing link in the reasoning is the relation between choosing and craving. This missing link, in other words the underlying assumption, in the argument is that craving leads to choosing. However option A merely states the opposite of this assumption and hence cannot be a statement supporting the argument.

B. CORRECT. For an argument X causes Y, the weakening statement could be Z causes Y (implying it's not X that causes Y). Therefore a strengthening statement could be Z does NOT cause Y. Here X = Aldolase, Y = craving for sweets, Z = another chemical (which is found to cause cravings for sweet food among mice)

Thus this option confirms that another chemical which causes cravings for sweets in mice is NOT the reason for cravings of sweetened drinks among the subjects, and hence this option strengthens the argument that Aldolase indeed is the cause of the cravings.

C. This option supports the hypothesis why similar concentrations of Aldolase is found in the brains after taking sweetened or salty drinks, i.e. this option considers Aldolase concentration as the effect of some action, i.e., taking sweetened or salty drinks. Hence this option does not have any relevance to the argument because the argument is about Aldolase being the cause of cravings for sweetened drinks.*

D. This option is a weakening statement. For an argument X causes Y, a weakening statement could be Y causes X (reversal of causation). Here X = Aldolase, Y = craving for sweetened drink.

Thus this option establishes that taking sweetened drinks increases the concentrations of Aldolase and not the other way round, i,e. Aldolase does not cause the cravings for sweetened drinks.

E. Like option C, this option also considers concentrations of Aldolase as an effect of something, here, low metabolism of sugar. Hence this option does not have any relevance to the argument because the argument is about Aldolase being the cause of cravings for sweetened drinks.*

*Note: Nonetheless, cause-effect reversal is useful to be examined when dealing with weakening statements, as in option B above.


Answer: B