Pioneered by scientists at Los Alamos National Laboratory, BEAM robots

Dear Friends,

Here is a detailed explanation to this question-

Meaning is crucial to solving this problem:
Understanding the intended meaning is key to solving this question; the intended meaning of this sentence is that BEAM robots were by scientists at Los Alamos National Laboratory, and these robots use brainlike circuits called neural networks to learn to walk through trial and error rather than being programmed to walk.

Concepts tested here: Meaning + Modifiers + Tenses + Verb Forms + Parallelism + Awkwardness/Redundancy

• Only those parts of a sentence should be parallel that play the same role in the sentence.
• Information that is permanent in nature is best conveyed through the simple present tense.
• In a “phrase + comma + noun” construction, the phrase must correctly modify the noun; this is one of the most frequently tested concepts on GMAT sentence correction.
• “being” is only to be used when it is part of a noun phrase or represents the passive continuous verb tense; the use of passive continuous must be justified in the context.

A: Correct. This answer choice correctly uses "Pioneered by scientists at Los Alamos National Laboratory" to modify "BEAM robots", conveying the intended meaning - that BEAM robots were pioneered by scientists at Los Alamos National Laboratory. Moreover, Option A uses the clauses "BEAM robots are not programmed to walk" and "they use...neural networks to learn to walk through trial and error", conveying the intended meaning - that all BEAM robots use neural networks specifically in order to learn to walk through trial and error, rather than being programmed to walk. Further, Option A correctly uses the simple present tense verb "use" to refer to information that is permanent in nature. Additionally, Option A is free of any awkwardness or redundancy.

B: This answer choice alters the meaning of the sentence through the phrase "instead of by programming them"; the parallelism between "using brainlike circuits called neural networks" and "programming them" illogically implies that BEAM robots use neural networks to learn to walk through trial and error rather than programming neural networks to learn to walk through trial and error; the intended meaning is that BEAM robots use neural networks to learn to walk through trial and error rather than being programmed to walk; remember, only those parts of a sentence should be parallel that play the same role in the sentence.

C: This answer choice alters the meaning of the sentence through the phrase "and learning"; the construction of this phrase incorrectly implies that BEAM robots use neural networks and as a separate action learn to walk through trial an error; the intended meaning is that BEAM robots use neural networks in order to learn to walk through trial an error. Further, Option C incorrectly uses the present participle ("verb+ing" - "using" in this sentence) to refer to information that is permanent in nature; remember, information that is permanent in nature is best conveyed through the simple present tense. Additionally, Option C incorrectly uses the word "being", leading to awkwardness and redundancy; remember, “being” is only to be used when it is part of a noun phrase or represents the passive continuous verb tense; the use of passive continuous must be justified in the context.

D: This answer choice incorrectly uses "Pioneered by scientists at Los Alamos National Laboratory" to modify "brainlike circuits called neural networks", incorrectly implying that neural networks were pioneered by scientists at Los Alamos National Laboratory; the intended meaning is that BEAM robots were pioneered by scientists at Los Alamos National Laboratory; remember, in a “phrase + comma + noun” construction, the phrase must correctly modify the noun. Moreover, Option D further alters the meaning of the sentence through the phrases "instead of programming" and "BEAM robots learning to walk through trial and error"; the construction of these phrases incorrectly implies that those specific BEAM robots that learn to walk through trial and error use neural networks for all purposes instead of programming; the intended meaning is that all BEAM robots use neural networks specifically to learn to walk through trial and error, instead of being programmed to walk.

E: This answer choice incorrectly uses "Pioneered by scientists at Los Alamos National Laboratory" to modify "brainlike circuits called neural networks", incorrectly implying that neural networks were pioneered by scientists at Los Alamos National Laboratory; the intended meaning is that BEAM robots were pioneered by scientists at Los Alamos National Laboratory; remember, in a “phrase + comma + noun” construction, the phrase must correctly modify the noun. Moreover, Option E further alters the meaning of the sentence through the phrases "instead of being programmed" and "BEAM robots that learn to walk through trial and error"; the construction of these phrases incorrectly implies that those specific BEAM robots that learn to walk through trial and error use neural networks for all purposes instead of programming; the intended meaning is that all BEAM robots use neural networks specifically to learn to walk through trial and error, instead of being programmed to walk. Further, Option E incorrectly uses the word "being", leading to awkwardness and redundancy; remember, “being” is only to be used when it is part of a noun phrase or represents the passive continuous verb tense; the use of passive continuous must be justified in the context.

Hence, A is the best answer choice.

To understand the concept of "Simple Tenses", you may want to watch the following video (~2 minutes):



To understand the concept of "Phrase Comma Subject" and "Subject Comma Phrase" on GMAT, you may want to watch the following video (~1 minute):



To understand the use of "Being" on GMAT, you may want to watch the following video (~2 minutes):



All the best!
Experts' Global Team
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A seems fine

B: 'instead of by' - awkward
C: obviously wrong
D & E: change meaning - robots and not brainlike circuits were pioneered by scientists

OA is A

I was confused with option D, as reading the first time a reader can also think that its 'brain like circuits' and not 'Robots'. Moreover, if you read the rest of the sentence in option D you'll find that, though it has a different meaning, it is grammatically correct sentence. Any suggestions??

'Pioneered by scientists at Los Alamos National Laboratory' should modify 'BEAM Robots'

B is out for passive and awkward - by using brainlike circuits............instead of by programming them.

C is incorrect - being programmed

D and E are out for modifier issue

A it is.

i have more reason to eliminate B. It is because "them" is ambiguous. We dont know whether "them" refers to "robots" or "circuits".

OA is A. However, how can "instead they use brainlike circuits called neural networks to learn to walk through trial and error" stand by itself as it should because of the ;

Thoughts on that.
Thanks.

hi, it is simply that OA is always correct answer so that rather than questioning the OA, we should find out why other choices are incorrect. Let me try to attack the four incorrect options. Plz let me know if i make any wrong elucidation in concept.
Pioneered by scientists ... --> what is pioneered here? it must be Robot --> eliminate D,E for wrong modifier. This is dangling error.
C: is wrong in tense which is using present participle. The original meaning does not focus on what is happening but what happens. Moreover, it is wrong in meaning. The robot use brain to learn not :use brain and learn
B: is wrong in meaning when it says that Robots learn X by using Y instead of programing them--> robots program themselves? Ridiculous right?

I understand why B, C, D, and E are wrong.

My question is how can A be correct taking into account how the ; is used in that answer.

Thanks.

[/quote]
i, interesting question noboru, i should have understood your query on usage of ";" here. to my limited knowlege, ";" is use when we have 2 independent clauses which have close meaning with each other. S1+V1; S2+V2.
I've found the very helpful elaboration from jnelson0612 , a manhattan gmat staff that helps us elucidate this confuse.
https://www.manhattangmat.com/forums/hi- ... 11430.html
hope it helps

i, interesting question noboru, i should have understood your query on usage of ";" here. to my limited knowlege, ";" is use when we have 2 independent clauses which have close meaning with each other. S1+V1; S2+V2.
I've found the very helpful elaboration from jnelson0612 , a manhattan gmat staff that helps us elucidate this confuse.
https://www.manhattangmat.com/forums/hi- ... 11430.html
hope it helps[/quote]

Thanks.

I guess that the point here is that "instead they use brainlike circuits called neural networks to learn to walk through trial and error" is actually an independent clause. The word "instead" was confusing me, and I thought that it was not an independent clause.
Thoughts?

actually we were on the same page. The first time i saw the sc which uses "instead" i think the word is a conjunction word like "but" or "and".
However "instead" is adverb so the second clause is an independent clause indeed. You can check your dictionary to confirm my search.

Stated that you can pioneer both BEAM robots and brainlike circuits, let's walk through the answers.

B) sounds like robots are programming circuits, when scientists are.
C) there's no parallelism at all. Robots are not being programmed (they are subjected to an action), but using (who's using?)
D) for BEAM robots learning to walk is wrong.
E) this one is a mess.

Answer A.
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The modifier “Pioneered by scientists at Los Alamos National Laboratory” should modify “BEAM robots”, so BEAM robots must follow the comma. This eliminates D and E.

In B, according to the parallelism, "them" would refer to the circuits, not the robots. Tn fact, "them" can't refer to the robots in this construction, because "robots" is actually still the subject at this point. If "them" were to refer to the robots, it'd have to appear as "themselves" - which would be grammatically ok, but still ABSURD.

C uses the present continuous tense (passive). Continuous tenses denote a moment, not a period of time. WRONG meaning here! Also, there is no contrast word in C; as we are discussing 2 contrasting ideas, we must have a contrast word.

A semi-colon serves to connect two complete sentences that are closely related in meaning.
A: “BEAM robots are not programmed to walk; instead they use brain like circuits.”
Here,” instead they use brain-like circuits” is a complete sentence in which ” instead” serves as an introductory modifier.
The purpose of “instead” is to express that the second action (“they use”) happens IN PLACE OF the proceeding action (“are programmed”).
Conveyed meaning:
“BEAM robots are not programmed. “
“Instead” -- meaning IN PLACE OF THIS ACTION – “BEAM robots USE BRAIN-LIKE CIRCUITS. “
A: correct

Pioneered by scientists at Los Alamos National Laboratory, BEAM robots are not programmed to walk: instead they use brainlike circuits called neural networks to learn to walk through trial and error.

A. BEAM robots are not programmed to walk; instead they use brainlike circuits called neural networks to learn to walk through trial and error--- correct

B. BEAM robots learn to walk through trial and error by using brainlike circuits called neural networks instead of by programming them--- instead of is incorrect usage

C. BEAM robots are not being programmed to walk but instead using brainlike circuits called neural networks and learning to walk through trial and error --- unparallel and a fragment

D. brainlike circuits called neural networks are used instead of programming for BEAM robots learning to walk through trial and error-- 1. modification error 2. instead of is wrong.

E. brainlike circuits called neural networks are being used for BEAM robots that learn to walk through trial and error instead of being programmed ----1. modification error 2. instead of is wrong
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The answer is A
The reasoning for this question is that the scientists developed beam Robots
So D and E are out
Instead of by is wrong in B
C is wordy and there is shift in meaning as well
It suggests that the robots are programmed not to walk but to use circuits
A is the only possible choice

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