GRE Practice Tips: How to Tackle Reading Comprehension Critical Reasoning Weaken Questions

GRE sample test-takers who sift through many GRE mock questions may be aware that among the 40 multiple choice questions in the verbal part, there will be 5-6 questions on the sub-category of Reading Comprehension called Critical Reasoning. There are several types of Critical Reasoning (CR) questions in GRE. These include Strengthen, Weaken, Assumption, Inference, Bold-Faced, and Fill-in-the-blank, among others.

Many students find the Critical Reasoning Weaken questions quite challenging. In this article on GRE practice tips, we are going to show you how to tackle Critical Reasoning Weaken questions with ease.

Common Types of Critical Reasoning Weaken Questions in GRE

Before we give you our GRE practice tips, let’s look at the most common type of CR Weaken question. Typically, this type involves a cause-effect argument.

The argument could be of the form Fact implies Conclusion, or Reason Implies Fact.

Consider the following:

In a certain town, leaded petrol began to be sold. During the same period, the town experienced a substantial rise in pollution levels. The author of the argument concludes that leaded petrol is the cause of the rise in pollution.

The above argument is of the form Reason implies Fact.

To weaken the above argument, we need to show that there is another reason for pollution, quite apart from leaded petrol. Or, we could show that the given reason is impossible.

An example of a reason other than leaded petrol could be: “Cars in the town had faulty carburetors.” Another possible answer could read: “Many polluting factories began operation at that time.”

To show that the given reason is impossible, we could have an option that says, “Most cars in the town used diesel for fuel.”

Some more GRE mock questions

The number of people 85 or older in the United States started increasing dramatically during the last 10 years. The good health care that these people enjoyed during their vulnerable childhood is primarily responsible for this trend.

Which of the following, if true, most seriously weakens the explanation above?

A.   Seventy-five percent of the people in the United States who are 85 or older are the children of people who themselves lived less than 65 years.

B.    The people in the United States who are now 85 represent an age group that was smaller in numbers at birth than the immediately preceding and succeeding age groups.

C.    Thirty-five percent of the people of the United States who are 85 or older require some form of twenty-four-hour nursing care.

D.   Many of the people in the United States who are 85 or older immigrated to the United States when they were 20 or older.”

E.    Because of decreased federal funding for medical care for pregnant mothers and children, the life expectancy of United States citizens is likely to decrease.

The above is an example of a Critical Reasoning Weaken question in the form of Reason Implies Fact. To weaken the argument, we can show a reason other than good healthcare in childhood for the longevity of people in the United States. Alternately, we can show that the given reason is impossible.

The correct answer is: “Many of the people in the United States who are 85 or older immigrated to the United States when they were 20 or older.”

As you can see, according to this answer, good healthcare received in childhood could never be the cause of the longevity enjoyed by people in the United States during the last 10 years. How could people have received such healthcare in the United States, if they came to the United States only after the end of their childhood?

Here’s the next one:

Persons imprisoned for violent street crimes often commit the same crimes again after being released. Persons imprisoned for white-collar crimes such as receiving bribes or embezzlement, however, typically do not, after being released, repeat the crimes for which they have been imprisoned. It is fair to conclude that imprisonment, while it often fails to change the behavior of violent street criminals, does succeed in making white-collar criminals unwilling to repeat their crimes.

Which of the following, if true, would seriously weaken the conclusion stated above? The percentage of those who commit

A.   Statistics show that persons convicted of committing white-collar crimes rarely have a prison record.

B.    The percentage of those who commit white-collar crimes and are imprisoned for doing so is lower than the percentage of those who commit violent street crimes and are imprisoned for doing so.

C.    White-collar criminals whose prison sentences are shortened return to criminal activities at a slightly higher rate than white-collar criminals who serve their full sentences.

D.   Persons released from prison after white-collar crimes are seldom given high positions or access to other people’s money.

E.    Persons who commit violent street crimes seldom commit white-collar crimes, and vice-versa.

 

The above is another example of Critical Reasoning Weaken question in the form of Reason implies Fact: the argument concludes that imprisonment is the cause of non-repetition of crime by white-collar criminals.

The correct answer is: “persons released from prison after white-collar crimes are seldom given high positions or access to other people’s money.” The answer clearly shows that given the opportunity, white-collar criminals may repeat the crime. Hence, imprisonment does not cure them as concluded.

Another type of Critical Reasoning Weakens question you may encounter in the GRE an argument which assumes a cause-effect relationship that does not exist at all. Consider, for instance: Highly successful footballers own luxury cars. Therefore, in order to score more goals in football, buy a luxury car.

The fallacy in the above argument is that the author assumes a cause-effect relationship between ownership of a luxury car and scoring of football goals when the two are merely incidental facts.


Logical Connective That Can Help Solve Critical Reasoning Weaken GRE Mock Questions

 

We are going to show you a logical connective that could prove useful in solving certain types of CR weaken questions.

A typical logical statement in CR weakens questions is of the form, “If P, then Q.”

This can be expressed as a logical connective of the form, P implies Q

To make this clearer, we can define P as “The son comes first in his class.”

Additionally, we can define Q as “The father gives the son a reward.”

Further, we can define P’ as “The son does not come first in his class.”

We can define Q’ as “The father does not give the son a reward.”

Now, we can consider the various permutations possible:

PQ, P’Q, PQ’, and P’Q’

PQ is possible. In other words, P and Q can co-exist: if the son comes first in his class, the father will reward him.

P’Q and P’Q’ are also possible. The father may or may not give the son a reward if he does not come first in his class.

But PQ’ (“the son comes first yet the father does not give him a reward “) is not possible.

From this, we may surmise that whenever Q’ is true, P’ must be true.

In other words, Q’ implies P’.

Therefore, whenever P implies Q, Q’ implies P’ must be true.

Consider the following:

A program of steady, moderate exercise coupled with a diet low in saturated fats and cholesterol has been associated with reduced risk of heart attacks and strokes. Therefore, no one who exercises regularly and eats only foods that are low in saturated fats and cholesterol will have a heart attack or stroke.

Of the following, the best criticism of the argument above is that the argument does not

A.   take into account the possibility of heart attacks and strokes that occur regardless of diet and level of exercise.

B.    take into account all of the possible physiological effects of saturated fats and cholesterol.

C.    specify whether foods high in saturated fats also contain cholesterol.

D.   Indicate whether an increased risk of heart attacks and strokes is due more to poor diet or more to lack of exercise.

E.    differentiate between the cause of heart attacks and the cause of strokes.

 

We can solve this question using the logical connective shown above.

We can define P as “a program of steady, moderate exercise coupled with a diet low in saturated fats and cholesterol,” and Q as “reduced risk of heart attacks and strokes.”

Thus, according to the first sentence of the argument, P implies Q.

In the second sentence, “no one who exercises regularly ad eats only foods that are low in saturated fats and cholesterol” can be defined as P’, while “will have a heart attack or stroke” can be defined as Q’.

In other words, given that P implies Q, the argument has concluded that P’ implies Q’.

From the logical connective explained in the earlier paragraph, we can surmise that P’ implies Q’ would be a valid conclusion only if the premise was Q implies P, and not P implies Q.

In other words, the argument is weak because the author makes the wrong assumption that Q implies P. In other words, the author assumes that “absence of heart attacks and strokes” necessarily implies “a program of steady, moderate exercise coupled with a diet low in saturated fats and cholesterol.”

Thus, the argument does not take into account the possibility of heart attacks and strokes that occur regardless of diet and level of exercise.

Interestingly, the logical connective discussed above can also be used to solve CR Strengthen questions:

Consider the following:

Studies in restaurants show that the tips left by customers who pay their bill in cash tend to be larger when the bill is presented on a tray that bears a credit card logo. Consumer psychologists hypothesize that merely seeing a credit-card logo makes many credit cardholders willing to spend more because it reminds them that their spending power exceeds the cash they have immediately available.

Which of the following, if true, most strongly supports the psychologists’ interpretation of the studies?

A.   The effect noted in the studies is not limited to patrons who have credit cards.

B.    Patrons who are under financial pressure from their credit-card obligations tend to tip less when presented with a restaurant bill on a tray with a credit-card logo than when the tray has no logo.

C.    In virtually all of the cases in the studies, the patrons who paid bills in cash did not possess credit cards.

D.   In general, restaurant patrons who pay their bills in cash leave larger tips than do those who pay by credit card.

E.    The percentage of restaurant’s bills paid with a credit card increases when that credit card logo is displayed on the tray with which the bill is presented.

To use the logical connective to solve this question, we define P as “larger cash tips,” and Q as “high spending power.” If P implies Q, Q’ implies P’. In other words, lower cash tips imply lower spending power. Hence the correct answer is option B: Patrons who are under financial pressure from their credit-card obligations tend to tip less when presented with a restaurant bill on a tray with a credit-card logo than when the tray has no logo.


Summary

Redefine the given Critical Reasoning Weaken question in the form of Reason implies Fact or Fact implies Conclusion. Choose the answer option that attacks the non-fact (i.e. reason or conclusion).

These GRE tips are meant to help you crack the Critical Reasoning Weaken questions in quick time. But the best GRE practice tip we can give you is to ask you to solve as many GRE practice tests as you can. As the saying goes, practice makes perfect.