Critical Reasoning

It is widely assumed that people need to engage in intellectual activities such as solving crossword puzzles or mathematics problems in order to maintain mental sharpness as they age. In fact, however, simply talking to other people�that is, participating in social interaction, which engages many mental and perceptual skills�suffices. Evidence to this effect comes from a study showing that the more social contact people report, the better their mental skills. Which of the following, if true, most seriously weakens the force of the evidence cited?

Guillemots are birds of Arctic regions. They feed on fish that gather beneath thin sheets of floating ice, and they nest on nearby land. Guillemots need 80 consecutive snow-free days in a year to raise their chicks, so until average temperatures in the Arctic began to rise recently, the guillemots� range was limited to the southernmost Arctic coast. Therefore, if the warming continues, the guillemots� range will probably be enlarged by being extended northward along the coast. Which of the following, if true, most seriously weakens the argument?

A new law gives ownership of patents�documents providing exclusive right to make and sell an invention�to universities, not the government, when those patents result from government-sponsored university research. Administrators at Logos University plan to sell any patents they acquire to corporations in order to fund programs to improve undergraduate teaching. B Corporate sponsors of research in university facilities are entitled to tax credits under new federal tax-code guidelines. C Research scientists at Logos University have few or no teaching responsibilities and participate little if at all in the undergraduate programs in their field. D Government-sponsored research conducted at Logos University for the most part duplicates research already completed by several profit-making corporations. E Logos University is unlikely to attract corporate sponsorship of its scientific research.

In the United States, of the people who moved from one state to another when they retired, the percentage who retired to Florida has decreased by three percentage points over the past ten years. Since many local businesses in Florida cater to retirees, these declines are likely to have a noticeably negative economic effect on these businesses and therefore on the economy of Florida. Which of the following, if true, most seriously weakens the argument given?

Advertising by mail has become much less effective, with fewer consumers responding. Because consumers are increasingly overwhelmed by the sheer amount of junk mail they receive, most discard almost all offers without considering them. Thus, an effective way for corporations to improve response rates would be to more carefully target the individuals to whom they mail advertising, thereby cutting down on the amount of junk mail each consumer receives. Which of the following, if true, would most support this recommendation?

Historian: Fifteenth-century advances in mapmaking contributed to the rise of modern nation-states. In medieval Europe (from the fifth to the fifteenth century), sovereignty centered in cities and towns and radiated outward, with boundaries often ambiguously defined. The conceptual shift toward the modern state began in the late fifteenth century, when mapmakers learned to reflect geography accurately by basing maps on latitude-longitude grids. By the mid-seventeenth century, nearly all maps showed boundary lines. Which of the following would, if true, most strengthen the historian's reasoning?

Which of the following most logically completes the passage? Most bicycle helmets provide good protection for the top and back of the head, but little or no protection for the temple regions on the sides of the head. A study of head injuries resulting from bicycle accidents showed that a large proportion were caused by blows to the temple area. Therefore, if bicycle helmets protected this area, the risk of serious head injury in bicycle accidents would be greatly reduced, especially since ________.

A major network news organization experienced a drop in viewership in the week following the airing of a controversial report on the economy. The network also received a very large number of complaints regarding the report. The network, however, maintains that negative reactions to the report had nothing to do with its loss of viewers. B The viewers who registered complaints with the network were regular viewers of the news organization's programs. C Major network news organizations publicly attribute drops in viewership to their own reports only when they receive complaints about those reports. D This was not the first time that this network news organization has aired a controversial report on the economy that has inspired viewers to complain to the network. E Most network news viewers rely on network news broadcasts as their primary source of information regarding the economy.

Economist: The price of tap water in our region should be raised drastically. Supplies in local freshwater reservoirs have been declining for years because water is being used faster than it can be replenished. Since the price of tap water has been low, few users have bothered to adopt even easy conservation measures. The two sections in boldface play which of the following roles in the economist's argument?

In the past, most children who went sledding in the winter snow in Verland used wooden sleds with runners and steering bars. Ten years ago, smooth plastic sleds became popular; they go faster than wooden sleds but are harder to steer and slow. The concern that plastic sleds are more dangerous is clearly borne out by the fact that the number of children injured while sledding was much higher last winter than it was ten years ago. Which of the following, if true in Verland, most seriously undermines the force of the evidence cited?

A prominent investor who holds a large stake in the Burton Tool Company has recently claimed that the company is mismanaged, citing as evidence the company's failure to slow down production in response to a recent rise in its inventory of finished products. It is doubtful whether an investor's sniping at management can ever be anything other than counterproductive, but in this case, it is clearly not justified. It is true that an increased inventory of finished products often indicates that production is outstripping demand, but in Burton's case it indicates no such thing. Rather, the increase in inventory is entirely attributable to products that have already been assigned to orders received from customers. B The first states a generalization that underlies the position that the argument as a whole opposes; the second clarifies the meaning of a specific phrase as it is used in that generalization. C The first provides evidence to support the conclusion of the argument as a whole; the second is evidence that has been used to support the position that the argument as a whole opposes. D The first provides evidence to support the conclusion of the argument as a whole; the second states that conclusion. E The first and the second each provide evidence against the position that the argument as a whole opposes.

The percentage of households with an annual income of more than $40,000ishigherinMertonCountythaninanyothercounty.However,thepercentageofhouseholdswithanannualincomeof$60,000 or more is higher in Sommer County. If the statements above are true, which of the following must also be true?

To reduce productivity losses from employees calling in sick. Corporation X implemented a new policy requiring employees to come into work unless they were so sick that they had to go to a doctor. But a year after the policy was implemented, a study found that Corporation X's overall productivity losses due to reported employee illnesses had increased. Which of the following, if true, would best explain why the policy produced the reverse of its intended effect?

Several industries have recently switched at least partly from older technologies powered by fossil fuels to new technology powered by electricity. It is thus evident that less fossil fuel is being used as a result of the operations of these industries than would have been used if these industries had retained their older technologies. Which of the following, if true, most strengthen the argument above?

According to a study, after a week of high-altitude living, twenty men had slimmed down. The men, middle-aged residents of low-altitude areas, had been taken to a research station at 2,650 meters (8,694 feet) above sea level. They had unrestricted access to food and were forbidden vigorous exercise, yet they lost an average of 1.5 kilograms (3.3 pounds) during their one-week stay. Clearly, the lower availability of oxygen at higher altitudes, or hypobaric hypoxia, can be said to have caused the weight loss, since __________. Which of the following would, if true, most logically complete the argument?

Between 1980 and 2000 the sea otter population of the Aleutian Islands declined precipitously. There were no signs of disease or malnutrition, so there was probably an increase in the number of otters being eaten by predators. Orcas will eat otters when seals, their normal prey, are unavailable, and the Aleutian Islands seal population declined dramatically in the 1980s. Therefore, orcas were most likely the immediate cause of the otter population decline. Which of the following, if true, most strengthens the argument�?

Enterprise Bank currently requires customers with checking accounts to maintain a minimum balance or pay a monthly fee. Enterprise plans to offer accounts with no monthly fee and no minimum-balance requirement; to cover their projected administrative costs of $3peraccountpermonththeyplantocharge$30 for overdrawing an account. Since each month on average slightly more than 10 percent of Enterprise's customers overdraw their accounts, bank officials predict the new accounts will generate a profit. Which of the following, if true, most strongly supports the bank officials� prediction?

Chaco Canyon, a settlement of the ancient Anasazi culture in North America, had massive buildings. It must have been a major Anasazi center. Analysis of wood samples shows that some of the timber for the buildings came from Chuska and San Mateo Mountains, 50 miles from Chaco Canyon. Only a major cultural center would have the organizational power to import timber from 50 miles away. In the argument given, the two portions in boldface play which of the following roles?

During the 1980s and 1990s, the annual number of people who visited the Sordellian Mountains increased continually, and many new ski resorts were built. Over the same period, however, the number of visitors to ski resorts who were caught in avalanches decreased, even though there was no reduction in the annual number of avalanches in the Sordellian Mountains. Which of the following, if true in the Sordellian Mountains during the 1980s and 1990s, most helps to explain the decrease?

Politician: Hybrid cars use significantly less fuel per kilometer than nonhybrids. And fuel produces air pollution, which contributes to a number of environmental problems. Motorists can save money by driving cars that are more fuel efficient, and they will be encouraged to drive hybrid cars if we make them aware of that fact. Therefore, we can help reduce the total amount of pollution emitted by cars in this country by highlighting this advantage of hybrid cars. Which of the following, if true, would most indicate a vulnerability of the politician's argument?