Reading ComprehensionDifficulty: Hard

PT13 S3 P1 Q5 Explanation

Neuron Formation

A free, expert breakdown of this official LSAT Reading Comprehension question.

TopicsLocal PurposeScience

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Passage

A major tenet of the neurosciences has been that all neurons (nerve cells) in the brains of vertebrate animals are formed early in development. An adult vertebrate, it was believed, must make do with a fixed number of neurons: those lost through disease or injury are not replaced, and cells but through modification of connections among existing ones.

However, new evidence for neurogenesis (the birth of new neurons) has come from the study of canary song. Young canaries and other songbirds learn to sing much as humans learn to speak, by imitating models provided by their elders. Several weeks after birth, a young bird produces its first rudimentary attempts at acquires new songs, and by the next breeding season it has developed an entirely new repertoire.

Recent neurological research into this learning and relearning process has shown that the two most important regions of the canary’s brain related to the learning of songs actually vary in size at different times of the year. In the spring, when the bird’s song is highly developed and uniform, the regions are all the brain cells needed to process and retain all the information gathered over a lifetime.

Although the idea of neurogenesis in the adult mammalian brain is still not generally accepted, these findings might help uncover a mechanism that would enable the human brain to repair itself through neurogenesis. Whether such replacement of neurons would disrupt complex learning processes or long-term memory is not known, but songbird research brain and to learn how to activate them in the adult brain.

What this question is testing

Local Purpose

Your task

Identify why the author included the referenced detail at that point in the passage — its function, not its content.

Common trap

Answers that merely repeat or summarize the topic of the detail instead of describing the role it plays.

Winning move

Ask what job the detail does for the paragraph, then for the passage's broader point.

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

The question
5.

The use of the word “vocabulary” (second paragraph) serves

Answer choices

  1. Dictionary-Trap: grammar6% picked this

    demonstrate the presence of a rudimentary grammatical structure in

    This is baiting students with their mental definition of how we usually use "vocabulary", in the sense of human speech. The passage was never suggesting that canaries' songs have a grammatical structure.

  2. Dictionary-Trap: syllables12% picked this

    point out a similarity between the patterned groupings of sounds in a canary’s song and the

    This is also baiting students with their mental definition of how we usually use "vocabulary", in the sense of human speech. The passage was never talking about how canary songs were similar to the syllables in human words. The passage as just using "vocabulary" as a proxy for "a canary's set of musical sounds".

  3. Contradicted6% picked this

    stress the stability and uniformity of the canary’s song throughout

    The author wouldn't be stressing the uniformity of the canary's song throughout its lifetime, because the 2nd paragraph is telling us that the song basically dies after every breeding season and then a new one is invented by the following breeding season.

  4. Correct69% picked this

    suggest a similarity between the possession of a repertoire of words among humans and a repertoire

    Why this is right

    This is a weird answer to pick, because it does still seem to have a dictionary-trap aspect to it ("a repertoire of words" is essentially what we think of when we talk about someone's vocabulary). But we were looking for an answer to match up "vocabulary" with a canary's "repertoire of song", and this is the answer that best does that.

    Skill tested: Local Purpose · how this choice captures the passage's function is the move to repeat next time.

  5. Too Strong7% picked this

    imply that the complexity of the canary’s song repertoire is equal to that

    Too Strong: equal Out of Scope: complexity There's nothing in the 2nd paragraph about the canary song repertoire being "complex". And it would be a very surprising and extreme comparison to say that the canary's song repertoire is identically complex to human language.

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