LSAT 126 – Section 3 – Question 11

LSAT 126 - Section 3 - Question 11

October 2008

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT126 S3 Q11
+LR
Flaw or descriptive weakening +Flaw
Causal Reasoning +CausR
A
3%
157
B
86%
163
C
10%
157
D
0%
151
E
1%
152
129
141
153
 +Easier 144.364 +SubsectionEasier

Biologist: Many paleontologists have suggested that the difficulty of adapting to ice ages was responsible for the evolution of the human brain. But this suggestion must be rejected, for most other animal species adapted to ice ages with no evolutionary changes to their brains.

A
It fails to address adequately the possibility that even if a condition is sufficient to produce an effect in a species, it may not be necessary to produce that effect in that species.
We don’t know whether there was a condition that was sufficient to affect species. The evidence concerns species who were not affected by ice ages.
B
It fails to address adequately the possibility that a condition can produce a change in a species even if it does not produce that change in other species.
This points out that even if ice ages did not affect other species’ brains, they could still have affected human brains.
C
It overlooks the possibility that a condition that is needed to produce a change in one species is not needed to produce a similar change in other species.
The issue is whether ice ages were sufficient to produce a change in human brains, not whether they were necessary to produce a change.
D
It presumes without warrant that human beings were presented with greater difficulties during ice ages than were individuals of most other species.
If anything, the author assumes the opposite. The author assumes that humans did not have greater difficulties than other animals. This is why the author thinks if ice ages didn’t affect other animals’ brains, they didn’t affect human brains either.
E
It takes for granted that, if a condition coincided with the emergence of a certain phenomenon, that condition must have been causally responsible for the phenomenon.
The author does not try to conclude causation from the fact two things occurred together. The conclusion is that ice ages did not cause changes in human brains.

The question stem reads: The biologist’s argument is most vulnerable to criticism on which one of the following grounds? This is a Flaw question.

The biologist begins by describing how many paleontologists suggest that the difficulties of the ice age were a cause of the evolution of the human brain. The biologist concludes those palentologists are wrong. In other words, the ice age was not responsible for the evolution of the human brain. As evidence, the biologist cites that many animal species survived the ice age with no evolutionary changes to their brain.

The biologist has hypothesized that the ice age was not repsonsbile for the evolution of the human brain. If we were to construct an ideal experiment to test this hypothesis, what kind of subjects would you want to use? You would want to use human brains! However, the biologist instead uses animals brains as evidence. The question is, “Are humans and animals” the same? Maybe. Maybe not. The biologist’s argument relies on the assumption that humans and animals would respond to the evolutionary pressures of the ice age in the same way. So let’s look for an answer choice that distinguishes how animal brains and human brains would respond to the ice age.

Answer Choice (A) is incorrect. The biologist does not suggest that the ice age was sufficient or necessary to produce brain evolution in humans or animals.

Correct Answer Choice (B) draws the distinction between humans and animals that we are looking for. The biologist fails to consider the possibility that the ice age could have produced the evolution of the brain in humans without producing the evolution of the brain in other species.

Answer Choice (C) is incorrect. The argument is not about whether the ice age was necessary for producing changes in the brains of humans or animals. The argument is about whether the ice age was sufficient to bring about changes in the brains of humans and animals.

Answer Choice (D) is incorrect. The biologist never presumes that humans had a more difficult time during the ice age than animals.

Answer Choice (E) is incorrect. The biologist does not presume that the ice age was causally responsible for the evolution of human brains. He concludes that the ice age was not casusualy responsible for the evolution of human brains.

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LSAT PrepTest 126 Explanations

Section 1 - Logical Reasoning

Section 2 - Reading Comprehension

Section 3 - Logical Reasoning

Section 4 - Logical Reasoning

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