3. Recent research in neuropsychology suggests that laughter is less a response to humor than a kind of involuntary social signal. In one study, a social scientist observed instances of laughter in diverse settings, and found that 80 to 90 percent occurred after straight lines such as “talk to you later” and “I know”.
The argument above depends on which of the following unstated assumptions?
Involuntary social signals can be studied with observational methods.
The diverse settings in the study included diverse populations as well.
Statements can be removed from context without any loss of meaning.
People laugh after straight lines because they believe they are expected to.
Humor and laughter are one and the same.
This question asks you to find the unstated assumption in the argument. The argument is structured like so: the conclusion (a general rule) is stated first, followed by evidence supporting the conclusion (an instance of this rule). The conclusion states the general rule that laughter is most often an involuntary social signal, not a response to humor. A recent study claiming that 80 to 90 percent of laughter occurs after “straight lines” is presented as evidence of the general rule. This is the vital point of the argument. If the study is not an instance of the general rule, then the evidence doesn’t support the conclusion, and the argument is invalid.
Choice A is an assumption upon which the study depends, but not the conclusion. Choice B strengthens the credibility of the study. Choice C must be true for the argument to be valid: if it is false, and statements must be studied in context, then the fact that that 80 to 90 percent of laughter occurs after “straight lines” doesn’t necessarily imply that those lines aren’t used humorously in context. Choice D is an unfounded inference. Choice E states the opposite of what’s stated in the conclusion.
Choice C is the only statement that must be true for the argument to work, and is therefore the best choice.
SOURCE : https://www.lsat-center.com/lsatc4s6.htm