fozzzy wrote:
Can someone explain why A is incorrect?
A study of marital relationships in which one partner's sleeping and waking cycles differ from those of the other partner reveals that such couples share fewer activities with each other and have more violent arguments than do couples in a relationship in which both partners follow the same sleeping and waking patterns. Thus, mismatched sleeping and waking cycles can seriously jeopardize a marriage.
This is one of the all time favorite things for the gmat.
This is a case of cause/reaction that can we reversed. What if the unhappy couples decided to sleep at different times, so that mismatched sleeping cycles are a RESULT of an unhappy marriage (not the cause)? The argument says "mismatched sleeping ==> jeopardized marriage", but what of "mismatched sleeping <== jeopardized marriage"
Which of the following, if true, most seriously weakens the argument above?
(A) Married couples in which both spouses follow the same sleeping and waking patterns also occasionally have arguments than can jeopardize the couple's marriage.
The argument does not states that "Married couples in which both spouses follow the same sleeping and waking patterns" do not have arguments, it states that have FEWER arguments, so option A does not weaken the argument because the argument does not rely on this extreme position:
"Married couples in which both spouses follow the same sleeping and waking patterns have no argument (...)"
(D) People in unhappy marriages have been found to express hostility by adopting a different sleeping and waking cycle from that of their spouses.
D is the correct answer because exposes the other possibility (that things happen the other way round).