In the phenomenon known as blindsight, some people who have been diagn

In the phenomenon known as blindsight, some people who have been diagnosed as completely blind through damage to their visual cortex retain the ability to make judgments and take actions that appear to require or demonstrate the use of sight, despite the fact that they consciously see nothing. Such an individual, if prompted, might catch a ball thrown to him, walk around obstacles without having been told obstacles are present, or guess with unusual accuracy whether an array of dots is moving or stationary. Individuals with blindsight are usually not surprised by these events and attribute them to coincidence.

Which of the following questions indicates the most serious weakness in the explanation described above?

A. Why don't people who are blind since birth exhibit similar abilities through coincidence?

B. Why are they not surprised by these events?

C. Why do such individuals tend refuse to accept the suggestion that the events are not coincidence?

D. If it feels like total blindness, but it is not functionally total blindness, is it still coincidence?

E. If it's coincidental, then why does it happen repeatedly?

E is correct since it indicates the most serious weakness in the explanation.
If it's coincidental, then why does happen repeatedly.

In the phenomenon known as blindsight, some people who have been diagnosed as completely blind through damage to their visual cortex retain the ability to make judgments and take actions that appear to require or demonstrate the use of sight, despite the fact that they consciously see nothing. Such an individual, if prompted, might catch a ball thrown to him, walk around obstacles without having been told obstacles are present, or guess with unusual accuracy whether an array of dots is moving or stationary. Individuals with blindsight are usually not surprised by these events and attribute them to coincidence.

Argument brings an ambiguity in that a person completely blind through visual cortex still has the ability to judge and act which would normally require use of sight as if they are able to see but they don’t. But these individuals refer their surprising actions as coincidence. How’s that possible? What if they can see a little but that is not possible since argument says they are blind and can’t see? What if what they say as coincidence is actually not one?

Which of the following questions indicates the most serious weakness in the explanation described above?

A. Why don't people who are blind since birth exhibit similar abilities through coincidence? – WRONG. Not concerned about people who are blind by birth.

B. Why are they not surprised by these events? – WRONG. This does raise valid question. We can keep it.

C. Why do such individuals tend refuse to accept the suggestion that the events are not coincidence? – WRONG. Similar to point B above this raises question. We can keep it.

D. If it feels like total blindness, but it is not functionally total blindness, is it still coincidence? – WRONG. Argument says its blindness so we can’t counter it by saying it is not functionally total blindness.

E. If it's coincidental, then why does it happen repeatedly? – CORRECT. Coincidence can’t repeat itself and if it can then these people are hiding something? We don’t know but this does raise eyebrows.

Options B and C are wrong since more assumptions are to be made to prove them correct.

IMO Answer (E).

In the phenomenon known as blindsight, some people who have been diagnosed as completely blind through damage to their visual cortex retain the ability to make judgments and take actions that appear to require or demonstrate the use of sight, despite the fact that they consciously see nothing. Such an individual, if prompted, might catch a ball thrown to him, walk around obstacles without having been told obstacles are present, or guess with unusual accuracy whether an array of dots is moving or stationary. Individuals with blindsight are usually not surprised by these events and attribute them to coincidence.

Which of the following questions indicates the most serious weakness in the explanation described above?

A. Why don't people who are blind since birth exhibit similar abilities through coincidence? out of scope

B. Why are they not surprised by these events? doesnot weaken the conclusion. Questions the conclusion

C. Why do such individuals tend refuse to accept the suggestion that the events are not coincidence? Irrelevant

D. If it feels like total blindness, but it is not functionally total blindness, is it still coincidence? Irrelevant

E. If it's coincidental, then why does it happen repeatedly. Weakens the conclusion that by stating if it was co-incidence then why would it occur repeatedly. Best option which weakens the conclusion

Weaken the conclusion that the Individuals in blind sight are able to find objects by co-incidence.

OFFICIAL EXPLANATION:

Reading the question: when we read this question, it may be difficult to avoid reading the answer choices, the questions, without having made a prediction first. But this impulse can be counterproductive, because the less helpful the answer choices are, the more you'll need an exact filter, such as a prediction, to evaluate them.

Creating a filter: the stem says, What's the most serious weakness in the explanation described above? We try to get more specific about what exactly the explanation is. It's the view of the individuals with blindsight. There are two things stated: they are not surprised, and they attribute their unusual abilities to coincidence. We're not sure whether both parts are the explanation or just the coincidence part. It must be the coincidence part: that's an opinion, whereas the lack of surprise is more a feeling. So, the right answer will undermine the idea that this is really happening by coincidence. That's our filter, the critical detail.

Applying the filter: Which answer choices undermine coincidence? Choice (A) does; it attacks the coincidence theory. (B) and (C) focus on the attitudes of the people with blindsight, not the coincidence explanation, so we will knock them out. (D) is trying to redefine what coincidence is, and it appears to take as granted that the individuals are not functionally totally blind, but they believe that they are. So (D) is out. Choice (E) does not attack the coincidence explanation. Coincidental events do happen repeatedly; some repetition, in and of itself, is not odd. It's rather that these coincidences happen so much more often than with people who are originally blind. That rules out (E) and leads us straight back to (A), which must be the correct answer.

The correct answer is (A).

This part of the official explanation misunderstands the meaning of the word "repeatedly". It does not mean "happens with some repetition". It means "constantly". If I take ten practice tests, and get a 500 on three of them, and an 800 on seven of them, I cannot correctly say that I "repeatedly" scored 500 on my practice tests. That's not what the word means. By the definition of words, "coincidental events" cannot happen "repeatedly" - if they do, they're not coincidental.

This question has two equally correct answers, A and E. What is the source?

GMAT Free.

Thank you, Ian. Archiving the topic!