Ornithologist: This bird species is widely thought to subsist primarily on vegetation, but my research shows that this belief is erroneous. While concealed in a well-camouflaged blind, I have observed hundreds of these birds every morning over a period of months, and I estimate that over half of what they ate consisted of insects and other animal food sources.

A
assumes, without providing justification, that the feeding behavior of the birds observed was not affected by the ornithologist’s act of observation
The author notes that she was concealed behind a “well-camouflaged blind” — so there is some justification for the assumption that the feeding wasn’t affected. In any case, the author just needs to assume that the birds didn’t change the vegetation/non-veg. makeup of their diet.
B
fails to specify the nature of the animal food sources, other than insects, that were consumed by the birds
The point of the observation is that the birds ate mainly non-vegetation in the morning. The particular kinds of food don’t matter as long as they’re not vegetation.
C
adopts a widespread belief about the birds’ feeding habits without considering the evidence that led to the belief
The author rejects the widespread belief that that the bird eats primarily vegetation.
D
neglects the possibility that the birds have different patterns of food consumption during different parts of the day and night
If the birds might have different patterns of food consumption at other times of day, that opens the possibility that the bird could eat primarly vegetation at other times of day. So the author’s observations of the birds’ diet might not be representative of the overall diet.
E
fails to consider the possibility that the birds’ diet has changed since the earlier belief about their diet was formed
If the birds’ diet has changed since the earlier belief was formed, that doesn’t undermine the author’s reasoning. The author is simply trying to prove that the bird doesn’t eat primarily vegetation.

The question stem reads: The reasoning in the ornithologist's argument is most vulnerable to criticism on the grounds that the argument… This is a Flaw question.

The ornithologist begins by stating how a particular bird species (we will call this bird "X") diet is believed to consist primarily of vegetation (plants). However, the ornithologist concludes that belief is wrong. In other words, The ornithologist argues that "X" birds' diets are mostly not plants. As evidence, he describes how he camouflaged himself and watched hundreds of "X" birds every morning for a month. During his morning observations, he estimates that over half of what "X" birds ate were insects and animal food resources (not plants). This line of reasoning is flawed because the ornithologist only observed birds during the morning. Let's say I hypothesized that the belief humans frequently drink coffee is wrong. To prove my theory, I hid in people's closets for many months and watched their bedtime routines. During my observations, I noticed very few people drank coffee. Hypothesis proven, right? No! The problem is that I only observed people at night when they were unlikely to drink coffee. The other problem is that I shouldn't hide in people's closets. An ideal experiment has a representative sample.

Similarly, the ornithologist has only observed what "X" birds eat in the morning. However, what "X" birds eat in the morning might be unrepresentative of their diet on the whole. Now that we have identified our flaw let's move to the answer choices.

Answer Choice (A) is wrong. The ornithologist says he camouflaged himself. You might argue that perhaps his camouflage was ineffective. However, our job LSAT flaw questions in the reasoning, not to question the truth of the premises. Even if he did camouflage himself well, his argument is still problematic (he was only watching "X" birds in the morning!).

Answer Choice (B) is wrong. The ornithologist does not need to describe exactly what kinds of food "X" birds ate. He needs to say that plants accounted for 50% or less of their diet. So if it was true that most of "X" birds' diets were insect and animal food sources, that would imply 50% or less of "X" birds' diet was plants.

Answer Choice (C) is wrong. The author does not adopt the widespread belief. The author rejects the widespread idea that "X" birds' diet is mostly plants.

Correct Answer Choice (D) is what we discussed. If it was confirmed that "X" birds have different feeding patterns throughout the day, the ornithologist made an error by taking an unrepresentative sample of the birds' diet.

Answer Choice (E) is incorrect. Mapping on the stimulus to (E), we would get: fails to consider the possibility that "X" birds diet has changed since the earlier belief that "X" birds mostly ate plants was formed. Even if it was true that the popular belief was formed when "X" birds used to mostly eat plants, what matters is what the birds eat now. If "X" birds mostly eat insects and animals, then the popular belief is wrong. Being right in the past doesn't make you any less wrong in the present.


16 comments

Since Jackie is such a big fan of Moral Vacuum’s music, she will probably like The Cruel Herd’s new album. Like Moral Vacuum, The Cruel Herd on this album plays complex rock music that employs the acoustic instrumentation and harmonic sophistication of early sixties jazz. The Cruel Herd also has very witty lyrics, full of puns and sardonic humor, like some of Moral Vacuum’s best lyrics.

Summarize Argument
Jackie will like The Cruel Herd’s new album. This is because she likes Moral Vacuum’s music, and The Cruel Herd’s new album sounds similar musically and lyrically.

Notable Assumptions
The author assumes that the differences between Moral Vacuum and The Cruel Herd’s music are insignificant. She assumes that the similarities alone are enough to confidently assert that Jackie will like The Cruel Herd’s new album.

A
Jackie has not previously cared for The Cruel Herd, but on the new album The Cruel Herd’s previous musical arranger has been replaced by Moral Vacuum’s musical arranger.
This strengthens the argument. It addresses potential weaknesses—that the similarities may not outweigh the differences—by suggesting that a key difference may have been changed to a similarity, as the two bands now share a musical arranger.
B
Though The Cruel Herd’s previous albums’ production quality was not great, the new album is produced by one of the most widely employed producers in the music industry.
This does not affect the argument. The argument is based on the similarities between Moral Vacuum and The Cruel Herd—the argument is not about whether the latter band’s music is objectively good, but whether Jackie, due to her inclination to similar music, will enjoy it.
C
Like Moral Vacuum, The Cruel Herd regularly performs in clubs popular with many students at the university that Jackie attends.
This does not affect the argument. There is no reason to believe that Jackie will enjoy The Cruel Herd’s music more because, like Moral Vacuum, it performs at a club her peers attend. Jackie may never even have been to this club.
D
All of the music that Jackie prefers to listen to on a regular basis is rock music.
This does not affect the argument. Jackie can only listen to rock music and still not like The Cruel Herd—liking rock music does not mean she likes all rock music. Maybe she only likes and listens to Moral Vacuum’s music and no other rock artists!
E
Jackie’s favorite Moral Vacuum songs have lyrics that are somber and marked by a strong political awareness.
This weakens the argument. It weakens the premise that draws similarities between some of the two bands’ lyrics, noting that they are both witty. If Jackie prefers the songs that are not witty, she may not be inclined to enjoy The Cruel Herd’s lyrics.

53 comments

Mayor: Local antitobacco activists are calling for expanded antismoking education programs paid for by revenue from heavily increased taxes on cigarettes sold in the city. Although the effectiveness of such education programs is debatable, there is strong evidence that the taxes themselves would produce the sought-after reduction in smoking. Surveys show that cigarette sales drop substantially in cities that impose stiff tax increases on cigarettes.

Summarize Argument: Phenomenon-Hypothesis
The author hypothesizes that heavily increasing taxes on cigarettes sold in the city would reduce smoking in the city. He bases this on surveys which show that cigarette sales drop substantially in cities that increase taxes on cigarettes.

Notable Assumptions
The author assumes that the survey captures a clear cause-and-effect relationship between higher taxes and lower smoking rates. He assumes that, because taxes are shown to decrease cigarette sales, a drop in cigarette sales would then cause a decrease in smoking. He ignores the possibility that people might seek cigarettes through other means.
He also assumes that what works in the cities with similar tax increases that are represented by the survey will also work in this particular city, without considering any local factors that might differ.

A
A city-imposed tax on cigarettes will substantially reduce the amount of smoking in the city if the tax is burdensome to the average cigarette consumer.
This does not undermine the reasoning in the argument. Instead, it presents a condition which, if met, would indeed reduce the amount of smoking in the city.
B
Consumers are more likely to continue buying a product if its price increases due to higher taxes than if its price increases for some other reason.
While (B) suggests there might be more effective ways to reduce cigarette purchases, it doesn't change the fact that higher taxes would have some effect. It also doesn't point out the author’s assumption that a reduction in purchases would lead to less smoking.
C
Usually, cigarette sales will increase substantially in the areas surrounding a city after that city imposes stiff taxes on cigarettes.
(C) weakens the author's argument by showing that people might find other ways to get cigarettes after the city’s tax increase. It thus demonstrates that a drop in cigarette purchases will not necessarily lead to less smoking, as the author assumed it would.
D
People who are well informed about the effects of long-term tobacco use are significantly less likely to smoke than are people who are not informed.
This implies that the city’s antismoking education programs could effectively reduce smoking. But it doesn’t undermine the author’s conclusion, which is that increased taxes on cigarettes would effectively reduce smoking.
E
Antismoking education programs that are funded by taxes on cigarettes will tend to lose their funding if they are successful.
Like (D), this speaks to the effectiveness of antismoking education programs; if they successfully reduce smoking, then they’ll lose their funding due to fewer cigarette purchases. However, it doesn't weaken the author's conclusion that higher cigarette taxes will reduce smoking.

25 comments

Beck: Our computer program estimates municipal automotive use based on weekly data. Some staff question the accuracy of the program’s estimates. But because the figures it provides are remarkably consistent from week to week, we can be confident of its accuracy.

Summarize Argument: Counter-Position
Beck concludes that the computer program for estimating weekly municipal automotive use is accurate, counter to the questions of some staff. This is supported by the claim that the program’s figures are consistent every week.

Identify and Describe Flaw
Beck uses information about consistency to draw a conclusion about accuracy, which presumes that consistency guarantees accuracy. This overlooks the possibility that, for example, the program could be inaccurate by the same amount every time, making it consistent but still inaccurate.

A
fails to establish that consistency is a more important consideration than accuracy
Beck doesn’t claim that consistency is a more important consideration than accuracy, but rather that consistency is proof of accuracy.
B
fails to consider the program’s accuracy in other tasks that it may perform
Beck is only discussing the program’s accuracy in the task of estimating municipal automotive use, so other tasks aren’t relevant.
C
takes for granted that the program’s output would be consistent even if its estimates were inaccurate
Beck actually assumes the opposite of this: that the program’s output would not be consistent if its estimates were inaccurate. In other words, that the program’s output being consistent means its estimates must be accurate.
D
regards accuracy as the sole criterion for judging the program’s value
Beck isn’t talking about accuracy as a criterion for judging the program’s value, just claiming that the program is indeed accurate.
E
fails to consider that the program could produce consistent but inaccurate output
Beck’s argument assumes that consistent output means the program is accurate, but this overlooks the possibility that the program is consistent but still inaccurate.

13 comments

Recently discovered bird fossils are about 20 million years older than the fossils of the birdlike dinosaurs from which the birds are generally claimed to have descended. So these newly discovered fossils show, contrary to the account espoused by most paleontologists, that no bird descended from any dinosaur.

Summarize Argument: Counter-Position
The argument concludes that no birds descended from dinosaurs, counter to a common claim. This is based on the discovery that some bird fossils predate the fossils of dinosaurs from which birds were previously thought to have descended, so those birds couldn’t have descended from those dinosaurs.

Identify and Describe Flaw
The argument takes evidence proving that certain birds didn’t descend from certain dinosaurs to support a conclusion that no birds descended from any dinosaurs. However, it’s still totally possible that other birds were descended from those birdlike dinosaurs, or even that the newly discovered birds were descended from even older dinosaurs.

A
draws a generalization that is broader than is warranted by the findings cited
The argument generalizes that the entire hypothesis of birds descending from dinosaurs must not be true, based on findings that only disprove certain birds descending from certain dinosaurs.
B
rejects the consensus view of experts in the field without providing any counterevidence
The argument rejects a described consensus view of experts, but this is based on the provided counterevidence of bird fossils which predate the fossils of their claimed dinosaur ancestors.
C
attacks the adherents of the opposing view personally instead of addressing any reason for their view
The argument doesn’t make any personal attacks, and does address at least one reason for the opposing view.
D
fails to consider the possibility that dinosaurs descended from birds
The argument only attempts to counter the hypothesis that birds descended from dinosaurs. The possibility that dinosaurs descended from birds is irrelevant (and clearly absurd).
E
ignores the possibility that dinosaurs and birds descended from a common ancestor
There’s no need for the argument to consider this possibility. The argument is only concerned with countering the hypothesis that birds descended from dinosaurs, not with providing any other hypotheses about evolution.

5 comments