PT17.S3.Q15 - babies who can hear and have hearing parents

allieh

http://7sage.com/lsat_explanations/lsat-17-section-3-question-15/
Kinda confused about this one, and why the anser is B. What does the vocal tract have to do with anything?

c.janson35

So the question is asking us which hypothesis would be most undermined based on the facts in the stimulus. We are told that deaf babies with deaf parents begin to make hand gestures that constitute babbling at about the same age as hearing babies start babbling. Babbling is a rudimentary stage of language according to the stimulus, "a precursor to speaking." Based on this information, the development of language competency could not require speech oriented vocal activity as B says, because the deaf babies that the stimulus discusses are babbling within the language system of signs, and therefore beginning their development of language competency, without such speech oriented vocal activity.


Said another way:

B can ultimately be diagrammed as: DLC-->SOA
"development of language competency (DLC) requires speech-oriented activity (SOA)"

Thus, to disprove or argue adjacent this as the question is asking us to do, we have to show the sufficient can exist without the necessary, which is exactly the information that stimulus provides us with.