LSAT 136 – Section 2 – Question 23

LSAT 136 - Section 2 - Question 23

June 2012

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Question
QuickView		 Type Tags Answer
Choices		 Curve Question
Difficulty		 Psg/Game/S
Difficulty		 Explanation
PT136 S2 Q23
+LR
Resolve reconcile or explain +RRE
Rule-Application +RuleApp
A
3%
156
B
87%
165
C
7%
158
D
2%
154
E
1%
151
140
148
156
 +Medium 146.855 +SubsectionMedium

As a general rule, the larger a social group of primates, the more time its members spend grooming one another. The main purpose of this social grooming is the maintenance of social cohesion. Furthermore, group size among primates tends to increase proportionally with the size of the neocortex, the seat of higher thought in the brain. Extrapolating upon the relationship between group size and neocortex size, we can infer that early human groups were quite large. But unexpectedly, there is strong evidence that, apart from parents grooming their children, these humans spent virtually no time grooming one another.

"Surprising" Phenomenon
Why did early humans spend almost no time grooming each other, even though we know they lived in large groups, and the general rule among primates is that the larger the group, the more time spent grooming?

Objective
The correct answer will show why early humans were an exception to the general rule about the relationship between group size and grooming. The correct answer might have something to do with the purpose of grooming, which the stimulus says was to maintain social cohesion among primate group members.

A
Early humans were much more likely to groom themselves than are the members of other primate species.
We’re trying to explain why humans spent almost no time grooming each other. Grooming one’s self is a different kind of grooming, and there’s no indication self-grooming serves the purpose of social cohesion.
B
Early humans developed languages, which provided a more effective way of maintaining social cohesion than social grooming.
This shows early humans had a replacement for social grooming. Because they had languages, they didn’t need to groom as much for the purpose of social cohesion.
C
Early humans were not as extensively covered with hair as are other primates, and consequently they had less need for social grooming.
The main purpose of social grooming was social cohesion. So, even if humans didn’t need to clean each other as much due to having less hair, we’d still expect significant social grooming for the purpose of social cohesion.
D
While early humans probably lived in large groups, there is strong evidence that they hunted in small groups.
This still tells us early humans lived in large groups. So, we’d still expect a lot of social grooming for the purpose of social cohesion.
E
Many types of primates other than humans have fairly large neocortex regions and display frequent social grooming.
If other primates, like humans have large neocortex regions, and engage in lots of social grooming, we’d expect humans to do the same.

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LSAT PrepTest 136 Explanations

Section 1 - Reading Comprehension

Section 2 - Logical Reasoning

Section 3 - Reading Comprehension

Section 4 - Logical Reasoning

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