LSAT Logical Reasoning : Weaken/Undermine

Study concepts, example questions & explanations for LSAT Logical Reasoning

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Example Questions

Example Question #21 : Determining Which Answer Most Weakens The Argument

It appears that warm temperatures tend to improve both productivity and attitudes. Empirical evidence supports the general assumption that outdoor temperatures affect the way people feel and, perhaps as a result, the amount they get done. These conclusions are drawn from a recent study which found that when temperatures increase at the beginning of spring people are more likely to smile, make more money than in the winter, greet strangers, and report that they are content with their lives.

Which of the following, if true, most weakens the argument?

Possible Answers:

Those who have recently begun to make more money than previously, are more likely to smile and greet strangers than those who have not

People who greet strangers and smile are happier than those who do not

People more often take vacations during the spring than they do during the winter

People are happier and more productive at the beginning and end of the spring than they are during the winter

People are less happy and productive in the fall than in the winter, even though temperatures are warmer in the fall

Correct answer:

People are less happy and productive in the fall than in the winter, even though temperatures are warmer in the fall

Explanation:

The argument claims that warm temperatures improve productivity and attitudes.  The argument depends on the results of a study and the study is undermined if people are happier and make more money in the fall than they do in the winter.  If this fact were true, then the study results might be caused by something other than temperature differences.

Example Question #21 : Determining Which Answer Most Weakens The Argument

Recent evidence has shown that there are a growing number of judges who are corrupt – that is, they are being paid, either with money or prestige, to rule in favor of certain parties.  This corruption does not end at the judicial level, however: it often extends into the executive and legislative branches, which contain officials who are often complicit in the bribery.  Therefore, to prevent such corruption, judges should not be appointed by the executive branch.  Rather, they must be elected by a direct vote of the people.

Which one of the following, if true, most seriously weakens the argument?

Possible Answers:

Judges who are bribed almost always have been in office for several years without ever being bribed, and have had no prior knowledge or indication that bribery would occur.

Bribery is most common among judges who belong to the same political party as the executive officials who appointed them.

Some of the officials in the executive branch who appoint judges are themselves elected officials, and are politically motivated to distance themselves from scandals.

The legislative branch is able to create new laws which limit the power of judges to control the fate of parties in the legal system.

Judges who are appointed can be removed from office every four years by a direct vote of the people.

Correct answer:

Judges who are bribed almost always have been in office for several years without ever being bribed, and have had no prior knowledge or indication that bribery would occur.

Explanation:

The argument, in essence, is that judges who are appointed are more likely to accept bribes and perpetuate corruption.  But if the judges who are bribed have no prior knowledge or history of bribery, it likely makes no difference whether they are appointed or elected (as far as corruption is concerned, anyway).  This weakens the argument, as it removes the possibility that particular judges are appointed with the intention of being bribed.  The other answer choices either weaken the argument only tangentially, or do not weaken it at all.

Example Question #21 : Weaken/Undermine

Video game designer: With the glut of violent video games currently being produced, there is an untapped market for games without such violence.  Sixty percent of parents with children under the age of 14 indicate that they are concerned with the levels of violence portrayed in the games their children play.  Clearly such parents would be inclined to purchase games with similar gameplay but less violence.  Therefore, we should focus our efforts on producing non-violent titles if we are to increase our profits.

Which one of the following, if true, would most weaken the video game designer’s argument?

Possible Answers:

Many children under the age of 14 who play violent video games do so without their parents’ knowledge.

Much of the violence portrayed in violent video games is unrealistic and meant to be humorous.

Surveys of parents with young children indicate that they strongly prefer to self-monitor their children’s video game playing rather than purchase censored titles.

Some violent video games contain parental control options which allow parents to reduce the amount of violence and inappropriate content that appears on screen.

Video games designed specifically for children have seen a 150 percent increase in sales over the past five years.

Correct answer:

Surveys of parents with young children indicate that they strongly prefer to self-monitor their children’s video game playing rather than purchase censored titles.

Explanation:

The designer is arguing that there will be increased profitability in creating non-violent games with gameplay similar to violent games.  If parents prefer to self-monitor their children’s video game playing rather than purchase such titles, this is evidence which directly counters the argument’s conclusion.  It thus weakens the argument.  The remaining answer choices either strengthen the argument or have little to no effect on the argument’s veracity.

Example Question #23 : Weaken/Undermine

Health coach: It is well-documented that mental stress often leads to temporary reduction in the immune system’s effectiveness. But recent studies have gone even further. These studies show that mental stress can actually permanently damage the immune system, thus leaving a person permanently vulnerable to disease and illness. So, it is now clear that purely mental states can permanently alter the body’s functioning, which proves that human beings are more than mere biological machines.

Which one of the following would, if true, most weaken the health coach’s argument?

Possible Answers:

Those who are susceptible to mental stress are more likely to get sick.

People with weakened immune systems who meditate regularly tend to manage their stress levels more effectively than those who do not meditate regularly.

Vitamins that boost the immune system’s effectiveness can also help individuals manage their stress levels.

Bodily exhaustion that leads to a weakening of the immune system generally makes a person susceptible to experiencing mental stress.

Those who chronically experience high levels of mental stress tend to expose themselves to toxic environments, which can lead to illness and disease.

Correct answer:

Bodily exhaustion that leads to a weakening of the immune system generally makes a person susceptible to experiencing mental stress.

Explanation:

The health coach is making a causation argument: One’s mental state can alter the functioning of one’s body. A classic way to undermine a causation argument is to show that the causation actually runs in the opposite direction. The correct answer choice here does precisely that. It reverses the “mind influences body” claim with the counter-assertion that “body influences mind.” That is to say, it states that the functioning of the body (i.e., bodily exhaustion) can affect mental states (i.e. mental stress). The answer choice involving exposure to toxic environments somewhat weakens the health coach’s claim, but it is a rather mild form of weakening, so it is not the best choice here.

Example Question #21 : Weaken/Undermine

Students who study for fewer than 30 minutes a day score an average of 60 on the final exam. Students who study between 30 minutes and 1 hour a day score an average of 65. Students who study between 1 and 2 hours a day score an average of 75. Students who study more than 3 hours a day score an average of 85. Therefore, the more a student studies, the higher the student is likely to score on the final exam.

Which of the following, if true, most weakens the argument above?

Possible Answers:

The sample size for the study was only 25 students.

Students who studied between 2 and 3 hours a day scored an average of 70.

Students who study longer tend to be more disciplined.

One student studied 45 minutes a day and scored an 85.

No student studied more than 4 hours a day.

Correct answer:

Students who studied between 2 and 3 hours a day scored an average of 70.

Explanation:

If students who studied between 2 and 3 hours a day averaged a final score of 70, they would average a lower score than students who studied only between 1 and 2 hours a day. This would directly contradict the argument offered that the more a student studies, the higher that student scores. The fact that one student studied 45 minutes a day and scored an 85 would also weaken the argument, but not as much as the correct answer choice. One student is more likely to be an outlier than the average of all students studying between 2 and 3 hours a day. Even if the latter is a small group of students, the group would be greater than one.

Example Question #22 : Determining Which Answer Most Weakens The Argument

Greater mass creates greater power. This applies to punching in the sport of boxing. The larger fighter generally has the power advantage when compared to a smaller fighter. Since the larger fighter has greater mass, the larger fighter necessarily creates greater power in his punches.

Which of the following most weakens the argument above?

Possible Answers:

Smaller fighters are quicker than larger fighters.

A fighter's defense is more important than his power. If a fighter has exceptional defense and is not hit, then power becomes irrelevant.

Larger fighters have slower reaction times than smaller fighters.

The speed with which a punch is thrown also determines its power and greater mass creates less speed.

The power in a punch does not affect the force with which it lands.

Correct answer:

The speed with which a punch is thrown also determines its power and greater mass creates less speed.

Explanation:

The fact that the speed with which a punch is thrown also determines power and the fact that greater mass creates less speed most weakens the argument above. While greater mass alone can create greater power, it may not do so if combined with other factors that affect power. If speed affects how much power a punch has and greater mass creates less speed, then a smaller fighter may have a more powerful punch than a larger fighter. The smaller fighter would then have the power advantage. The force with which a punch lands would be a separate metric from the power in a punch, and the argument more directly focuses on the power in a punch.

Example Question #81 : Lsat Logical Reasoning

We sent out surveys in the mail. Only 20 percent of those who received the surveys responded. Therefore, we concluded that sending surveys in the mail is not the best way to ensure a high response rate and that we should switch to another means of communication.

Which of the following, if true, most weakens the argument?

Possible Answers:

5 percent of surveys were sent to addressees who no longer lived at that location.

30 percent of those who received the survey did not have enough information to answer the questions.

Survey recipients were chosen at random.

The surveys did not include free return postage.

35 percent of those who received surveys in the mail never opened up the envelope.

Correct answer:

30 percent of those who received the survey did not have enough information to answer the questions.

Explanation:

If 30 percent of those who received the survey in the mail did not have enough information to answer the questions, then it would not matter by what means they received the survey. They still would not have enough information to answer the questions and respond. The fact that 35 percent of recipients never opened the envelope actually strengthens the overall argument. The fact that 5 percent of the surveys were not addressed correctly may both weaken and strengthen the overall argument, but not to a great degree either way. The fact that the surveys did not include free return postage does weaken the argument, but not as directly or as significantly as the fact that 30 percent could not answer the questions.

Example Question #21 : Weaken/Undermine

A recent university study concluded that a majority of its students are overweight. The university wants to immediately take steps to remedy this problem. It has demanded a review of the menus at the cafeteria, placed orders for new exercise equipment, and began plans for building a new jogging trail in the woods.

Which of the following, if true, would NOT support the university’s response?

Possible Answers:

Outdoor activity leads to greater weight loss than similar indoor activity.

Several of the pieces of exercise equipment purchased are designed to reduce the weight of their users.

The majority of students do not use on-campus facilities for recreation.

Physical exercise can contribute to weight loss.

The cafeteria’s menu currently does not feature very many low-fat meal options.

Correct answer:

The majority of students do not use on-campus facilities for recreation.

Explanation:

If the majority of students do not use on-campus recreation facilities, the exercise equipment and jogging trail may not help the weight problems of students on campus. Therefore, this fact would not directly support the university's response.

If the menu on campus already contains many low-fat choices, a review of the menu could lead to the university expanding such options or eliminating other options. Therefore, the answer choice discussing the menu is not the best answer choice.

Example Question #21 : Weaken/Undermine

Baseball has undergone a revolution in the past two decades, thanks to the introduction of advanced analytical methods. Baseball executives began applying statistical analysis to their decision-making progress, and the teams that first jumped on this bandwagon have been the most successful teams in recent years. Traditional baseball executives are a dying breed, and those that have lasted have been forced to adopt the new methods.

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

Possible Answers:

Certain baseball executives have argued that "advanced analytical methods" should include more than statistical analysis.

Traditional forms of analysis won championships in baseball for years before the introduction of advanced statistical analysis.

The precepts of "advanced statistical analysis" in baseball have not been taken up at the college or high-school levels of the game.

Advanced statistical analysts often have strong disagreements over what provides the most value in baseball.

"Traditional baseball executives" have won more games than "advanced analytic" executives over the past five seasons.

Correct answer:

"Traditional baseball executives" have won more games than "advanced analytic" executives over the past five seasons.

Explanation:

The argument is that "advanced statistical analysis" has generally taken over in most baseball front offices, killing off the "traditional methods." If it is true that the executives who have been most successful recently, which is defined by winning the most games, are the ones who follow "traditional" methods, then the overall argument is considerably weakened.

Example Question #22 : Weaken/Undermine

The chief driver of revolutionary political movements has always been poverty. When people are deprived of their basic needs, they will seek out ways to overthrow those in charge, especially violent means.

Which of the following, if true, does the most to undermine the above statement?

Possible Answers:

Revolutionary political movements are quite frequently unsuccessful in helping poor people.

Many succesful revolutionary movements have been led by individuals from the upper classes.

The biggest challenge faced by successful revolutionary political movements is in establishing a system to effect their original goals.

Non-violent means rarely are used to seek redress for grievances by poor people.

The biggest barrier to revolutionary political movements succeeding is frequently the upper classes.

Correct answer:

Many succesful revolutionary movements have been led by individuals from the upper classes.

Explanation:

The argument is essentially quite straightforward: that revolutionary political movements are not only rooted in poverty, but led by the poor. It is important to note that this is both stated as an absolute and only deals with the beginnings of such movements. Thus, the statement which most undermines the argument is that many upper-class individuals have helped begin revolutionary political movements.

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