As part of a new trend in the writing of history, an emphasis on the details of historical events and motivations has replaced the previous emphasis on overarching historical trends and movements, with the result that the latter are often overlooked. In consequence, the ominous parallels that may exist between historical trends and current trends are also overlooked, which lessens our ability to learn from history.

Summary
Newer interpretations when writing history emphasize the details and motivations behind historical events. This is unlike previous interpretations that emphasized overarching historical trends and movements. As a result of this shift parallels between historical events and current trends are overlooked, which lessens our ability to learn from history.

Strongly Supported Conclusions
A shift of what we focus on when interpreting historical events has lessened our ability to learn from history.

A
Studying the details of historical events and motivations lessens our ability to learn from history.
This answer is unsupported. The stimulus argues a different causal connection. The stimulus argues that shifting away from emphasizing overarching trends causes our ability to learn to decrease.
B
Overarching historical trends and movements can be discerned only when details of historical events and motivations are not emphasized.
This answer is unsupported. We don’t know from the stimulus what the connection is, if any, between the emphasis on details compared to the emphasis on overarching trends.
C
Those who attend to overall trends and movements in history and not to details are the best able to learn from history.
This answer is unsupported. We don’t know which group are best able to learn from history as compared to the other. It is possible that neither group is the best at learning from history.
D
A change in emphasis in the interpretation of history has lessened our ability to learn from history.
This answer is strongly supported. This answer correctly states the causal relationship in the stimulus between the shift in emphasis and our ability to learn from history.
E
History should be interpreted in a way that gives equal emphasis to overarching historical trends and movements and to the details of historical events and motivations.
This answer is unsupported. We don’t know from the stimulus what should or should not be done. It is possible that the author disagrees with both interpretations.

16 comments

George: Throughout the 1980s and early 1990s, hardly anyone learned ballroom dancing. Why is it that a large number of people now take ballroom dancing lessons?

Boris: It’s because, beginning in 1995, many people learned the merengue and several related ballroom dances. Because these dances are so popular, other ballroom dances are now catching on.

Summarize Argument
George asks why a large number of people are now taking ballroom dancing lessons, even though in the 1980s and 1990s, almost nobody took ballroom dancing lessons.

Boris’s answer is that in 1995, lots of people learned some ballroom dances, and this lead to other ballroom dances becoming popular.

Identify and Describe Flaw
George isn’t just asking “Why are lots of people taking ballroom dancing lessons?” He’s asking why so many people are taking ballroom dancing in light of the fact that it was unpopular in the past. In other words, George sees a discrepancy that needs to be explained.

Boris’s answer doesn’t help resolve the discrepancy. Pointing out that ballroom dancing started to become popular in 1995 doesn’t explain WHY it became more popular after a period of being unpopular.

A
show that the people who learned the merengue are the same people who are now interested in other ballroom dances
Boris didn’t need to show that the exact same people are now interested in other dances. Perhaps one person is inspired to dance because of a different person’s dancing. What Boris needed to explain was why ballroom dancing became popular, even though it was unpopular before.
B
explain why ballroom dancing was so unpopular before 1995
Boris didn’t need to explain why ballroom dancing was unpopular before 1995. He needed to explain how it became popular after 1995. There’s a difference between explaining why something used to unpopular and explaining why something became popular.
C
relate the merengue to the forms of dancing that were more prevalent before 1995
Boris didn’t need to relate the merengue to other kinds of dancing. The merengue is simply one kind of ballroom dance. What matters is why the merengue and other ballroom dances became popular in 1995.
D
account for the beginning of the revival of interest in ballroom dancing
Boris failed to explain why ballroom dancing started to become popular in 1995. George wasn’t just asking, “Why are lots of people interested in ballroom dance?” He asked what explains the unexpected new interest, given the lack of interest in the 80s and early 90s.
E
demonstrate that all types of ballroom dancing are currently popular
Boris didn’t need to show that all ballroom dancing types are popular. He just needed to explain why ballroom dancing in general became popular, despite its unpopularity in the 80s and early 90s.

38 comments

On the basis of relatively minor morphological differences, some scientists suggest that Neanderthals should be considered a species distinct from Cro-Magnons, the forerunners of modern humans. Yet the fact that the tools used by these two groups of hominids living in different environments were of exactly the same type indicates uncanny behavioral similarities, for only if they faced the same daily challenges and met them in the same way would they have used such similar tools. This suggests that they were members of the same species, and that the morphological differences are due merely to their having lived in different environments.

Summary
Some scientists think that Neanderthals are a different species from Cro-Magnons (the ancestors of modern humans) because of relatively minor morphological differences.

Both groups of hominids used exactly the same kinds of tools even in different environments.

The two groups would have used the same tools only if they faced the same daily challenges and met them in the same way.

The behavioral similarity shown in the tool use suggests that the two groups were members of the same species and that the morphological differences were from living in different environments.

Notable Valid Inferences
Cro-Magnons and Neanderthals faced the same daily challenges and met them in the same way.

A
Morphological differences between the members of two populations do not guarantee that the two populations do not belong to the same species.
This could be true. The stimulus leaves open the possibility that two populations have morphological differences and are members of the same species.
B
The daily challenges with which an environment confronts its inhabitants are unique to that environment.
This must be false. We know that the two species lived in different environments, and we also can logically infer that they faced the same daily challenges and met them the same way (because species use the same tools only if they face the same daily challenges).
C
There are greater morphological differences between Cro-Magnons and modern humans than there are between Cro-Magnons and Neanderthals.
This could be true. The stimulus does not give any information that allows us to compare the extent of morphological differences between different species.
D
Use of similar tools is required if members of two distinct groups of tool-making hominids are to be considered members of the same species.
This could be true. Use of similar tools is given as a sufficient condition for facing the same daily challenges; there is no information that prevents use of similar tools from being a necessary condition for being the same species.
E
Through much of their coexistence, Cro-Magnons and Neanderthals were geographically isolated from one another.
This could be true. We know that the two species were living in different environments; it could be the case that they were geographically isolated.

9 comments

Newspaper article: People who take vitamin C supplements tend to be healthier than average. This was shown by a study investigating the relationship between high doses of vitamin C and heart disease, which showed that people who regularly consume high doses of vitamin C supplements have a significantly lower than average risk of heart disease.

Summarize Argument
The author concludes that people who take vitamin C supplements tend to be healthier than average. This is because a study showed that people who regularly consume high doses of vitamin C supplements have a much lower than average risk of heart disease.

Notable Assumptions
The author assumes that taking vitamin C supplements doesn’t cause any harm to overall health that could outweigh the benefits of lower risk of heart disease. (Maybe vitamin C supplements lead to a higher risk of kidney disease? If so, we can’t conclude that people who take vitamin C supplements are healthier than average.)

A
Vitamin C taken in the form of supplements has a different effect on the body than does vitamin C taken in food.
The conclusion is about vitamin C supplements, and the study is also about vitamin C supplements. Whether vitamin C in food has different effects from vitamin C in supplements doesn’t affect the argument.
B
The reduction in risk of heart disease due to the consumption of vitamin C is no greater than the reduction due to certain other dietary changes.
The author never suggested eating vitamin C was the best way to reduce heart disease. There can be other dietary changes that reduce heart disease as much or more than vitamin C; this is consistent with the argument.
C
Taking both vitamin C supplements and vitamin E supplements lowers one’s risk of heart disease far more than does taking either one alone.
We know there’s a correlation between eating high doses of vitamin C supplements and having a lower risk of heart disease. The fact a combination of vitamins might reduce heart disease more doesn’t change the fact that there’s evidence vitamin C reduces heart disease risk.
D
High doses of vitamin C supplements tend to reduce slightly one’s resistance to certain common infectious diseases.
This points out a harmful effect of vitamin C supplements. This raises the possibility that this harmful effect might outweigh decreased risk of heart disease when it comes evaluating vitamin C supplements’ impact on overall health.
E
Taking vitamin C supplements has been found to lower one’s risk of developing cancer.
This is an additional benefit of vitamin C supplements. To weaken the argument, we want to point out a harm from vitamin C supplements.

43 comments

Chef: This mussel recipe’s first step is to sprinkle the live mussels with cornmeal. The cornmeal is used to clean them out: they take the cornmeal in and eject the sand that they contain. But I can skip this step, because the mussels available at seafood markets are farm raised and therefore do not contain sand.

Summary
The author concludes that he can skip the step of sprinkling live mussells with cornmeal.
Why?
Because mussels available at seafood markets are farm raised and don’t contain sand. Cornmeal is used to clean out sand in mussels.

Notable Assumptions
The author assumes that the mussels he’s about to prepare were obtained at a seafood market.
The author also assumes that there is no other reason cornmeal is used to clean live mussels out besides to get them to eject sand.

A
Cornmeal is not used to clean out farm-raised mussels before they reach seafood markets.
Not necessary, because even if cornmeal is used to clean out farm-raised mussels, the author is only arguing that he doesn’t need to use cornmeal. It may be that many people still use cornmeal when they don’t need to; that doesn’t undermine the argument.
B
Mussels contain no contaminants other than sand.
Not necessary, because other contaminants can be cleaned out by other steps. The author merely believes that he can skip the cornmeal step. But there may be other steps necessary to get rid of other contaminants.
C
Sprinkling the mussels with cornmeal does not affect their taste.
Not necessary, because we have no reason to think taste plays any role in the author’s reasoning. Let’s say cornmeal does affect taste — thta doesn’t suggest a reason the author can’t skip the cornmeal step.
D
The chef’s mussel recipe was written before farm-raised mussels became available.
Not necessary, because even if the recipe was written after farm-raised mussels became available, the recipe might have been assuming people didn’t have ready access to farm-raised mussels. In any case, the author’s argument is that he can skip a step in the recipe, so it’s not clear why he’d have to assume anything about when the recipe was written.
E
The mussels the chef is using for the mussel recipe came from a seafood market.
Necessary, because if it were not true — if the mussels the author is using are NOT from a seafood market — then the author can’t assume that the mussels do not contain sand. In other words, if (E) were not true, the author might not be able to skip the cornmeal step.

36 comments

Gardener: Researchers encourage us to allow certain kinds of weeds to grow among garden vegetables because they can repel caterpillars from the garden. While it is wise to avoid unnecessary use of insecticides, the researchers’ advice is premature. For all we know, those kinds of weeds can deplete the soil of nutrients and moisture that garden crops depend on, and might even attract other kinds of damaging pests.

Summarize Argument: Counter-Position
The gardener claims that researchers’ advice to allow certain caterpillar repelling weeds to grow with garden vegetables is premature. It is possible that growing those weeds has downsides that are unknown - like increasing the presence of other pests or depleting the soil - and could damage the garden crops.

Identify Conclusion
The conclusion is the gardener’s claim about the cited advice: “the researchers' advice is premature.”

A
To the extent that it is possible to do so, we should eliminate the use of insecticides in gardening.
This inaccurately rephrases a concession point in the author’s argument. The author agrees that unnecessary insecticide use should be avoided, but doesn’t go as far as to say use should be eliminated.
B
Allowing certain kinds of weeds to grow in vegetable gardens may contribute to a net increase in unwanted garden pests.
This is a possibility the gardener addresses in the premises to show that the advice is premature because it may have big drawbacks.
C
Allowing the right kinds of weeds to grow in vegetable gardens can help toward controlling caterpillars without the use of insecticides.
This is the researchers’ reasoning in the context for why they recommend growing certain weeds. The gardener brings up other considerations against that recommendation.
D
We should be cautious about the practice of allowing certain kinds of weeds to grow among garden vegetables.
This answer choice accurately rephrases the gardener’s conclusion. The researcher’s advice (growing certain weeds among garden vegetables) is premature (we should be cautious about it).
E
We should be skeptical about the extent to which certain kinds of weeds can reduce the presence of caterpillars in gardens.
The gardener does not refute the researchers’ claim that the weeds reduce caterpillars. She claims that although there may be that benefit, the advice is premature because it may have other downsides.

8 comments