Biological functions of many plants and animals vary in cycl

[catennacio]

Biological functions of many plants and animals vary in cycles that are repeated every 24 hours. It is tempting to suppose that alteration in the intensity of incident light is the stimulus that controls these daily biological rhythms. But there is much evidence to contradict this hypothesis.

Which of the following, if known, is evidence that contradicts the hypothesis stated in lines 2-5 above?

(A) Human body temperature varies throughout the day, with the maximum occurring in the late afternoon and the minimum in the morning.

(B) While some animals, such as the robin, are more active during the day, others, such as mice, show greater activity at night.

(C) When people move from one time zone to another, their daily biological rhythms adjust in a matter of days to the periods of sunlight and darkness in the new zone.

(D) Certain single-cell plants display daily biological rhythms even when the part of the cell containing the nucleus is removed.

(E) Even when exposed to constant light intensity around the clock, some algae display rates of photosynthesis that are much greater during daylight hours than at night.

OA is E

My question: is this a Cause-Effect Weakening question?
Intensity of incident light correlates with biological rhythm
Changes in intensity of light affects the biological rhythm.

According to the Ron's Thursday video (June 16, 2011: Critical Reasoning: A certain type of critical reasoning with blanks in the prompt Weakening cause-and-effect arguments - http://vimeo.com/25244924) we have 2 ways to do:
- A reverse relationship
- Another cause causes both the stated cause and effect

However OA does not follow any of the two mentioned above. Instead, it says that when there no change in intensity of incident light, the biological rhythm changes. So are the two above-mentioned ways to attack the conclusion the only two ways? Or there are others?

From CR Bible, there are more of them:
- Reverse relationship
- Z causes both X & Y
- Another cause causes the effect
- When the effect occurs, the cause does not occur (in order word, the cause is not the cause: this is the cause of OA here)
- When the cause happens, the effect does not happen
- Attack on the validity of the data.

Please close the gap for me. Thanks a lot!

[RonPurewal]

catennacio, please read my post here about approaching the problems in this kind of way:
post65695.html?sid=3e84f08c0a77ac6ddec22c609ebf217f#p65695

in this particular thread, you are approaching this kind of stuff in what is quite possibly the worst way imaginable. you've got so many "rules" and "templates" and so on floating through your head that there is simply no room left in your brain for you to think.

the bad news, for people who follow approaches like that, is the following: it is actually impossible to master critical reasoning with "formulas" and "rules".
in fact, there's a name for the effort to do this -- it's called "strong artificial intelligence" -- and, well, no one has even come close yet.

in fact, this is the entire reason why the gmat tests critical reasoning -- because you can't just memorize a bunch of rules. if you could, this part of the test would be absolutely useless for measuring what it's supposed to measure.

--

in this problem
* "the hypothesis" is that the 24-hour cycles are caused by changing amounts of light
* choice (e) presents a case in which the cycles can't be caused by changing amounts of light, because, well, the amounts of light aren't changing
* therefore, choice (e) is strong evidence against the hypothesis

i have no idea how you would "classify" the question -- but, since all such efforts will ultimately have limited success anyway, you shouldn't bother. instead, you should think about the situation (i.e., you should "reason critically").

[catennacio]

catennacio, please read my post here about approaching the problems in this kind of way:
post65695.html?sid=3e84f08c0a77ac6ddec22c609ebf217f#p65695

in this particular thread, you are approaching this kind of stuff in what is quite possibly the worst way imaginable. you've got so many "rules" and "templates" and so on floating through your head that there is simply no room left in your brain for you to think.

the bad news, for people who follow approaches like that, is the following: it is actually impossible to master critical reasoning with "formulas" and "rules".
in fact, there's a name for the effort to do this -- it's called "strong artificial intelligence" -- and, well, no one has even come close yet.

in fact, this is the entire reason why the gmat tests critical reasoning -- because you can't just memorize a bunch of rules. if you could, this part of the test would be absolutely useless for measuring what it's supposed to measure.

--

in this problem
* "the hypothesis" is that the 24-hour cycles are caused by changing amounts of light
* choice (e) presents a case in which the cycles can't be caused by changing amounts of light, because, well, the amounts of light aren't changing
* therefore, choice (e) is strong evidence against the hypothesis

i have no idea how you would "classify" the question -- but, since all such efforts will ultimately have limited success anyway, you shouldn't bother. instead, you should think about the situation (i.e., you should "reason critically").

Thanks for your reply. I just tried to recognize the pattern. I think we need to know which type of questions we are dealing with so that we have some tools at hand.

So my question: In the video you said there are two ways to attack. How do we use this info? Do we use it as a way to check the correct answer after we found it? Or do we use it to find the correct answer?

For example, when I scan the answer choices and after reasoning, one answer choice seems to fit with a pattern (e.g. one of the 2 ways mentioned to of this question type), can I conclude it a correct answer choice? It sounds like "classifying" as you said, but if we have ways to attack, are we not classifying?

Please shed some light.

Thanks,

-C

[tim]

I think you're missing Ron's point. You're still relying too much on rules and pattern recognition. Please understand that the methods we suggest are a good starting point, but there is no substitute for using your own reasoning to get to the final answer..