Among various logical problems in the Critical Reasoning section of the GMAT, the issue of causality is quite common. Let’s review the arguments containing this type of logical relation.
Here is an example from the Official Guide for GMAT 12th ed, p.497
40. In the last decade there has been a significant decrease in coffee consumption. During this same time, there has been increasing publicity about the adverse long-term effects on health of the caffeine in coffee. Therefore, the decrease in coffee consumption must have been caused by consumers’ awareness of the harmful effects of caffeine.
Which of the following, if true, most seriously calls into question the explanation above?
(A) On average, people consume 30 percent less coffee today than they did 10 years ago.
(B) Heavy coffee drinkers may have mild withdrawal symptoms, such as headaches, for a day or so after significantly decreasing their coffee consumption.
(C) Sales of specialty types of coffee have held steady as sales of regular brands have declined.
(D) The consumption of fruit juices and caffeine-free herbal teas has increased over the past decade.
(E) Coffee prices increased steadily in the past decade because of unusually severe frosts in coffee-growing nations.
This argument is a typical “causality” argument. It has all the three main features of such argument type:
It mentions two events, namely
a) “ there has been a significant decrease in coffee consumption” and
b) “ there has been increasing publicity about the adverse long-term effects on health of the caffeine in coffee”
It states that both events take place more or less simultaneously
a) “In the last decade”
b) “during this same time”
It assumes that a causal relation exists between the two events and determines on the basis of this assumption that one is the cause and the other is the effect
Therefore, the decrease in coffee consumption must have been caused by consumers’ awareness of the harmful effects of caffeine.
Now, whichever relation might or might not exist between the two events, the argument is definitely flawed because the above mentioned assumption is not supported by any additional premises and thus, is inevitably questionable. The author fails to prove that the connection between the two events is not merely coincidental or that the decrease in the coffee consumption is not caused by some other factors. Therefore, our argument might be an example of false causality.
Depending on the task that follows the argument, causality arguments can be improved by factoring in the premises supporting the causal relation between the two events, or weakened by refuting these premises and turning the questionable assumptions into the false ones.
In case of this particular problem the task demands that we “call into question” or weaken the argument. This means that we must prove that there is no causal relation between the two events or, if the relation exists, the former is not the cause and the latter is not the consequence, but may be vice versa. So let’s review the answer choices keeping in mind that we already know what we are looking for.
If we do so, if we specifically search for the option aimed at the core of the problem: the causal relation between the two premises, we’ll quickly come across the right one, answer choice (E).
This answer does exactly what we need, provides an alternative cause for cutting down on coffee: Coffee prices increased steadily in the past decade because of unusually severe frosts in coffee-growing nations. It clearly states that people started drinking less coffee because it became more expensive, not because of the negative publicity. What was to be demonstrated.
However, we can’t just simply discard all other answer choices, we need to look through them first to make sure they are unsuitable.
Answer choice (A) “On average, people consume 30 percent less coffee today than they did 10 years ago” does nothing to us but repeats the first premise of the argument. We already know that coffee consumption has decreased but this fact by itself doesn’t prove or disprove the idea that the decrease was caused by the publicity mentioned. So this answer is wrong.
Answer choice (B) “Heavy coffee drinkers may have mild withdrawal symptoms, such as headaches, for a day or so after significantly decreasing their coffee consumption” could support the author’s explanation as it mentions a negative effect caused by coffee and implies that the decrease in the coffee consumption could have been triggered by the information campaign. But it doesn’t cast doubt on our argument. Wrong again.
Answer choice (C) “Sales of specialty types of coffee have held steady as sales of regular brands have declined” is based on the shift of concept. It confuses purchasing and consuming and thus has nothing to do with this argument. This answer can easily be discarded.
And finally, answer choice (D) “The consumption of fruit juices and caffeine-free herbal teas has increased over the past decade” This answer choice implies that coffee drinkers have switched to the healthier options. Just as the answer choice (A), this option supports the premise that coffee consumption has decreased, however it neither buttresses nor ruins the statement that this decrease was somehow linked with the public awareness of the negative effects of caffeine. As option (D)is also obviously wrong, we can be sure that our answer choice (E) indeed “most seriously calls into question the explanation above”.
When dealing with causality or false causality arguments, look into the core of the problem: the causal relation itself. See whether it is real or coincidental, check whether what is considered the cause is the only factor possible and you will find the right answer quickly and easily.
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