Reading Comprehension

PT13 · S3 · P1 · Q5 Neuron Formation

A free, expert breakdown of this official LSAT Reading Comprehension 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

A major tenet of the neurosciences has been that all neurons (nerve cells) in the brains of vertebrate animals are formed early in development.

Topic

The discovery of neurogenesis (birth of new neurons) in adult canaries and its implications for neuroscience.

Framework

Old / New

Main Point

Although it was long believed that adult vertebrate brains could not generate new neurons, evidence from studies of canaries shows that adult neurogenesis does occur, which opens new possibilities for understanding and perhaps repairing the human brain. (Most valuable sentence: Final paragraph — )

P1: Traditional View in Neuroscience

For a long time, neuroscientists believed that adult vertebrate brains could not make new neurons; adults were stuck with the neurons they developed early on.

P2: Discovery Through Canary Song

Canaries learn new songs every year, losing and regaining their “vocabulary,” which suggests some sort of ongoing learning and brain change that's more dynamic than previously thought.

P3: Evidence of Neurogenesis in Canaries

Research shows that regions of the brain connected to song learning actually shrink and grow seasonally as the number of neurons decreases after breeding and then new neurons form before the next season. This likely happens because it would be impractical for a flying bird to carry all the neurons needed for a lifetime’s worth of songs.

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

demonstrate the presence of a
Dictionary-Trap: grammar
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.
6% picked this
point out a similarity between
Dictionary-Trap: syllables
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".
12% picked this
stress the stability and uniformity
Contradicted
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.
5% picked this
Correct
suggest a similarity between the
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.
69% picked this
imply that the complexity of
Too Strong
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.
7% 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