Logical Reasoning

PT136 · S2 · Q23 As a general rule, the larger

A free, expert breakdown of this official LSAT Logical Reasoning question.

  • Save & drill this skill — build targeted practice sets from questions like this one

  • Video walkthroughs — watch every question solved step by step

  • 81 official LSATs — as questions, timed sections & full-length tests

Start practicing free

As a general rule, the larger a social group of primates, the more time its members spend grooming one another.

Apparent Paradox

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.

Evaluate

If the main purpose of social grooming is social cohesion why didn’t these humans spend more time grooming one another? Maybe the large neocortex of these humans somehow reduced their need for maintaining social cohesion.

23.

Which one of the following, if true, would do most to resolve the apparent discrepancy described above?

  1. Early humans were much more

    Too Weak

    This fails to explain why early humans did so.

    4% picked this

  2. Correct

    Early humans developed languages, which

    Why this is right

    This explains how the main purpose of social grooming could be accomplished in some other way thereby reducing the need for these early humans to engage in social grooming.

    Skill tested: Paradox · how this choice captures the argument's function is the move to repeat next time.

    85% picked this

  3. Early humans were not as

    Contradiction

    The statements suggest that the primary reason for social grooming is to maintain social cohesion and this does not free the early humans from the need to maintain social cohesion.

    9% picked this

  4. While early humans probably lived

    Out of Scope

    Distinguishing the size of the group for hunting from the size of the group for living does not explain the lack of social grooming with these humans.

    2% picked this

  5. Many types of primates other

    Deepens the Paradox

    This makes it all the stranger why humans with large neocortex regions would not groom one another.

    1% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill
LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free