求解LSAT中一道weaken的经典问题

Doctors in Britain have long suspected that patients who wear tinted eyeglasses are abnormally prone to depression and hypochondria. Psychological tests given there to hospital patients admitted for physical complaints like heart pain and digestive distress confirmed such a relationship. Perhaps people whose relationship to the world is psychologically painful choose such glasses to reduce visual stimulation, which is perceived as irritating. At any rate, it can be concluded that when such glasses are worn, it is because the wearer has a tendency to be depressed or hypochondriacal。

 Each of the following, if true, weakens the argument EXCEPT:
(A) Some people wear tinted glasses not because they choose to do so but because a medical condition of their eyes forces them to do so.

(B) Even a depressed or hypochondriacal person can have valid medical complaints, so a doctor should perform all the usual objective tests in diagnosing such persons.

(C) The confirmatory tests were not done for places such as western North America where the usual quality of light differs from that prevailing in Britain.

(D) Fashions with respect to wearing tinted glasses differ in different parts of the world.

(E) At the hospitals where the tests were given, patients who were admitted for conditions less ambiguous than heart pain or digestive distress did not show the relationship between tinted glasses and depression or hypochondria

没有找到该题标准答案，参考答案是D，解释为D为无关项，但我觉得是它因，因为如果流行可以影响到戴tinted glasses ，那么就不能判断has a tendency to be depressed or hypochondriacal是戴眼镜的原因。

另求，B选项是无关项还是否定了调查的可行性。

谢谢！！

附上前人（不好意思……不知道出处）的分析

演绎题目中：前提一定是一个事实（做任何题目，只要看到事实就知道是个前提，比如有很多的题目是一帮反对什么东西，然后有很多原因，前提就是他们反对（这是一个事实），后面就是解释的原因！，另外一类题目是做什么调查，结果为什么东西，这个调查是个事实，也就是前提，后面当然也为解释！）
用这种方法思维，屡试不爽呀！来

A前提是个事实，
那也就是：Doctors in Britain have long suspected that patients who wear tinted eyeglasses are abnormally prone to depression and hypochondria。
（非常明显，这就是一个事实，那也就是前提A，无论任何情况之下都不能反对，选项也证明了这一点）
后面有两个B进行解释（且称为B1和B2）
B1就是：
Psychological tests given there to hospital patients admitted for physical complaints like heart pain and digestive distress confirmed such a relationship.
演绎方向为：因果型！
weaken，ETS的方向是他因解释前提！ 但选项中没有！
  另外一种思路就是断桥和他因反对B1  其中B、C都是说这个tests没有代表性，所以为断桥！
  E则直接说这个tests不对，为他因否认B1！
B2为：
Perhaps people whose relationship to the world is psychologically painful choose such glasses to reduce visual stimulation, which is perceived as irritating. At any rate, it can be concluded that when such glasses are worn, it is because the wearer has a tendency to be depressed or hypochondriacal。
在B2中又有一个演绎，
且称前提为小a，推测为小b
小a为：when such glasses are worn（这是一个事实）
小b为：the wearer has a tendency to be depressed or hypochondriacal。（解释）
演绎方向：因果型！
选项A为他因解释前提小a，为ETS非常喜欢的weaken方向。

推理思路十分经典，不过没有具体说明为何B选项能体现tests没有代表性，所以一时无法理解，请高人补充~谢

As for B, the chain would be broken at "decrease in VS --> decrease in PP"

麻烦详细说明下为什么broke the chain

另，不是很明白题目中的Psychological tests如何confirmed such a relationship，样本“hospital patients admitted for physical complaints”对实验有什么意义？？？

不理解…………

sounds there is a little confusion between B and D. D can be understood as: Fashions differ in different parts of the world. Please pay attention that the article does  not try to discuss the fashioins about wearing tinted glasses, even doesnot treat it as a fashion. it just tries to find the reason why someone wear tinted glasses. Maybe there are only a couple of people. So it does not relate to fashions. D is obviously the answer.

B questions the hidden conclusion the psychological tester try to arrive at: physical complaints cause depression and further wearing tinted glasses to ease the depression.

惊喜！感谢NN的指点！

可能我有些钻牛角尖了，我理解D选项的FASHION，觉得有两层意思，一是戴不戴，二是怎么戴。在第一种情况下，如果世界不同地方的FAHION可以决定一个人戴不戴tinted glasses的话，就是alternative explanation；可是如果是第二种情况，Fashions with respect to wearing tinted glasses指的是戴的方式全世界不同的话，显然是无关项……看来是阅读功底不足不能把握准确的意思。

而对B选项，实在没看懂a doctor should perform all the usual objective tests in diagnosing such persons和文章的推理链有什么关系，sigh!!!

the article say,"psychological tests.......confirm this relationship", that means it arrives at the conclusion that medical complaint cause depression and further cause the patients to wear tinted glasses. D say, "wait, before you come down to that conclusion, you better do some usual objective tests, rather than just do psychological tests and rush to get this conclusion. Maybe other reasons cause these patients to wear tinted glasses or other reasons cause the depression. 

恩，这就正好击中了我推理中最脆弱的环节了，我的理解是psychological tester的受众是那些有tendency to be depressed or hypochondriacal的病人，即physical complaints like heart pain and digestive distress 是d or h的症状，所以我一直认为 d or h cause medical complaint ，psychological tester假设了这部分有medical complaint 的人就是tendency to be depressed or hypochondriacal，而这部分人在test的过程中confirm
                this relationship，顺利成章的就引出的下面的结论。这里确实存在一个weak的可能，就是physical complaints 并不一定是d or h的症状，而是确实存在的病症。但在B里，第一句 Even a depressed or hypochondriacal person can have valid medical complaints就已经假设了病人是有d or h，对这部分病人做心里测试正是tester的预期，所以不管是否采用其他的test，都不能weaken psychological tests的结果。

另外，虽然超出本题目范围，但还是引征了一些医学上关于抑郁症的资料，很多病人以身体症状（如消化不良、心绞痛）为主诉到医院就诊，医生在诊断过程中需要判断到底他们是真的内科病还是是抑郁症等精神病，从而找出正确的症疗办法。显然psychological tester在这里犯了个错误，把所有physical complaints的病人都当作抑郁症的潜在病例。

谢谢lawyer,我一直按照你的方法来练习逻辑，确实受益匪浅，目前主要问题就是阅读了。