Logical ReasoningDifficulty: Easy

PT119 S2 Q7 Explanation

Although instinct enables organisms to

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

TopicsMust be True

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Stimulus

Although instinct enables organisms to make complex responses to stimuli, instinctual behavior involves no reasoning and requires far fewer nerve cells than does noninstinctual (also called flexible) behavior. A brain mechanism capable of flexible behavior must have a large number of neurons, and no of providing a sufficiently large number of neurons.

What this question is testing

Must be True

Conclusion

This is a fact-set, not an argument. Your job is to chain the facts and find what they force.

Evidence

The setup is a clean conditional chain. Flexible behavior requires a brain with many neurons. Insect brains do not have many neurons (at least not enough). Behavior is split into two types — instinctual or flexible.

Evaluate

Walk the chain. Insects don't have enough neurons → insects can't produce flexible behavior → if insect behavior exists, it must be the other kind, instinctual.

So everything insects do, behavior-wise, is instinctual. That's the modest, direct conclusion the facts force.

Watch out for trap answers that try to extend the inference to all organisms, to non-insects, to brain-elaborate organisms in general — the passage only gives us facts about insects specifically.

Goal

Pick the answer that says insect behavior is exclusively instinctual.

Reading along? Open the full official question in LawHub — we show a fragment here and keep the reasoning in our own words.

The question
7.

Which one of the following can be properly inferred from the

Answer choices

  1. Unsupported7% picked this

    The behavior of organisms with elaborate brain mechanisms is usually

    The passage tells us flexible behavior requires elaborate (large-neuron) brain mechanisms, but it doesn't tell us that organisms with elaborate brains usually do non-instinctual things. Such organisms have the capacity for flexible behavior, but the passage gives no information about how often they actually use it. They might still do mostly instinctual things.

  2. Correct83% picked this

    Insect behavior is exclusively

    Why this is right

    This follows from the chain. Flexible behavior requires a large number of neurons. Insect brains do not have a sufficiently large number of neurons. So insect brains cannot produce flexible behavior. Behavior is either instinctual or flexible (the passage's dichotomy). Therefore everything insects do, behavior-wise, must fall into the instinctual category — i.e., insect behavior is exclusively instinctual.

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

  3. Too Strong5% picked this

    All organisms with brains larger than insects’ brains are capable of some measure

    The passage tells us insects don't have enough neurons for flexibility, but it doesn't tell us all non-insect organisms with bigger-than-insect brains do. Some animals with brains larger than insects' might still fall short of the neuron threshold for flexibility. "All" is far too strong.

  4. Too Strong2% picked this

    All organisms with large brains are biologically equipped for

    "All organisms with large brains" is broader than the passage supports. The passage says flexible behavior requires a large number of neurons. Brain size and neuron count aren't identical (different species pack neurons at different densities), and the passage doesn't equate "large brain" with "many neurons" in general.

  5. Too Strong2% picked this

    Only organisms with brains of insect size or smaller engage in

    The passage tells us insects can only do instinctual behavior, but it doesn't tell us they're the only ones who do only instinctual behavior. There could be other organisms with similarly small brains (or insufficient neuron counts) that also engage exclusively in instinctual behavior. "Only insects" goes beyond what the passage supports.

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