#19 - Assumption, Author's Perspective

[Administrator]

Complete Question Explanation
(See the complete passage discussion here: lsat/viewtopic.php?t=10516)

The correct answer choice is (C)

For this question, we need to adopt the perspective of the author of passage B, and determine a questionable assumption underlying the argument made in passage A. Understanding the relationship between the two passages is once again key, as is the ability to quickly identify the assumptions upon which a given argument depends (a skill set usually tested in Logical Reasoning questions).

Answer choice (A): Neither author questions the idea of explaining the development of humans’ physical features in evolutionary terms.

Answer choice (B): This answer choice was almost twice as attractive as answer choice (C), garnering 46% of the responses to this question. One can see why: indeed, from the perspective of the author of passage B, it would be a mistake to assume that any action performed by an early human was necessarily orchestrated by that individual’s genes to promote the genes’ self-propagation. This is not, however, an assumption underlying the argument in passage A. The author of passage A never implied that any action performed by early humans can be explained in evolutionary terms—the focus of passage A was on only certain types of behavior (e.g. altruism) that defy simple evolutionary explanations.

To test whether answer choice (B) is correct, apply the Assumption Negation Technique and ask yourself if the logical opposite of that answer choice would weaken the argument made in passage A:


NOT ALL actions performed by an early human were necessarily orchestrated by that individual’s genes to promote the genes’ self-replication.


The author of passage A would respond by observing that even if not all types of behavior are prompted by genetically selfish motivations, certain types of behavior (such as altruism) might be. Since the logical opposite of answer choice (B) does not weaken the argument made in passage A, this answer choice is incorrect.

Answer choice (C): This is the correct answer choice. To test it, apply the Assumption Negation Technique and ask yourself if the logical opposite of this answer choice would weaken the argument made in passage A:

To explain a type of human behavior in evolutionary terms, it is NOT enough to show that the behavior would have improved the reproductive success of early humans.

This statement clearly weakens the argument made in passage A, which is only concerned with showing that the altruistic behavior of early humans would have improved their reproductive success. This, in turn, is taken as definitive evidence to show that altruism can be explained in evolutionary terms. Since the logical opposite of answer choice (C) weakens the argument made in passage A, answer choice (C) states an assumption upon which that argument depends.

Answer choice (D): Neither author alludes to the inability of evolutionary psychology to explain animal behavior. This answer choice falls entirely outside the combined scope of the two passages.

Answer choice (E): Neither passage makes any assumptions regarding what types of behaviors might have hindered the reproductive success of early humans, or whether they were eliminated by evolutionary competition. As with answer choices (A) and (D), this one falls outside the combined scope of the two passages.

[alee]

Regarding Q19, how do we differentiate between the following incorrect option:

(B) An action performed by an early human was necessarily orchestrated by that individual's genes to promote the genes' self-propagation.

and the correct option:

(C) To explain a type of human behaviour in evolutionary terms, it is sufficient to show that the behaviour would have improved the reproductive success of early humans.

I understand that the relevant section of Passage B is 'What is needed to make it decisive that a particular interest explains a particular behaviour is that the behaviour would be reasonable only if one had that interest. But such cases are vanishingly rare.' This suggests that for the evolutionary explanation to be a decisive one, the evolutionary motive must be the ONLY explanation for the behaviour. Is that it in terms of Q19?

[Adam Tyson]

That's absolutely right, alee - the author of Passage B is saying that it's not enough to show that an evolutionary theory could explain altruistic behavior. He is saying that if you want to prove that connection you have to show that there is no other possible motivation besides the evolutionary one.

A's author doesn't seem to assume that every action taken by early humans was based on an evolutionary motive, nor does B's author appear to think that's what he said. The discussion is limited only to certain behaviors - mainly altruistic behavior. In that regard answer B just goes too far, is too extreme, to attribute to author B as a criticism of author A.

Hope that helped! You already looked to be on the right track, and you're doing a fine job.

Adam M. Tyson
PowerScore LSAT Instructor

[miruke]

Hello,

I have a question about the comparive passage on the practice test 2 section 5 reading comprehension.Number 19.I really don't understand the questions I chose A but i can see how many evolutionary pressure wasn't the cause?But i don't get why C is correct.I don't think i fully understood this section.

Thanks!

[Robert Carroll]

miruke,

Understanding Question 19 depends on understanding the source of Passage B's critique of evolutionary psychology. The author of Passage B starts out by calling evolutionary psychology "a kind of conspiracy theory." The term "conspiracy theory" is meant to focus on the aspect of evolutionary psychology whereby behaviors like protecting one's children are not what they seem - as the author of Passage A (along with other people agreeing with the theory of evolutionary psychology) would put it, when a mother protects her child, she's not really doing that of her own free will, but because her genes have inculcated an instinctive need to propagate themselves by protecting her offspring. So, the "conspiracy theory" explanation of a mother helping her child is that her genes have actually overridden her conscious mind to promote their own interest. Because evolutionary psychology explains these behaviors in terms of hidden genetic motives, the author of Passage B calls it a "conspiracy theory."

That is the source of Passage's B's criticism. Passage A's author, and people with similar views, look for hidden motives in human behavior, and prefer those motives over the obvious motives. When the mother helps her child, there are two possible explanations, but the author of Passage A always chooses the "conspiracy theory" explanation. The author of Passage B points out, in lines 59-59, that the "hidden motive" aspect of evolutionary psychology makes sense only if it is the only explanation, not just one explanation among many. The mistake Passage A makes is thinking that proving the evolutionary psychology explanation as one possible explanation means proving it's inherently better than all other explanations.

Answer choice (A) fails to address the priority given to hidden motives in Passage A. The author of Passage B never expresses an opinion on whether most physical features of modern humans developed as a result of evolutionary pressures; that wasn't relevant to the argument. So this answer does not work.

Answer choice (C), on the other hand, reflects Passage B's criticism of Passage A: we could rephrase Passage B as saying, "You are wrong to think that proving one explanation possibly covers the facts is enough to establish that it, and only it, does cover the facts." This is what the author of Passage B thought the author of Passage A was doing - trying (illegitimately, according to Passage B) to show that genetic self-preservation definitely does cause a certain behavior if it can be proven that it could cause that behavior.


Let me know if you have any further questions!

Robert

[avengingangel]

Whoah! Thanks for explanations. I totally didn't even realize that this was an assumption question... I read the word assumption in the question stem, but thought of it more as a "Which of the following would the author of Passage B most agree with?" type of question...

I was initially going to post on the forum that I still didn't understand how B was wrong (although I understood why C is correct, I wasn't able to discern the difference between B & C, and feared that I almost certainly wouldn't be able to on test test, with the clock ticking). I was going to point to the fact that in Passage B, on lines 54-56 it states "There are, most often, all sorts of interests that would explain any given behavior" to justify B as still being correct... BUT when I realize that the question is asking what ASSUMPTION does the author of Passage A make as it would be described by the author of Passage B, I now see how the self-propagation of one's genes as the explanation for any action of early humans is not necessarily an assumption that the author of passage A has to make in order for them to hold their argument.

Thanks!

[bukkaabh]

Hello, I had a question regarding Answer Choice B and why it was wrong. In Passage A, the first sentence says that evolutionary psychology allows one to "explain a given type of human behavior by examining how it contributes to the reproductive success of individuals exhibiting the behavior, and thereby to the proliferation of the genetic material responsible for causing that behavior."

From the answer explanation, it seems that the problem with Choice B is that it says "any action...", but doesn't "given type of human behavior" mean the same as "any action"? From my understanding of the passage, I thought that altruism was just an example of a behavior being explained through the proliferation of genes, and this explanation would then extend to "any given behavior."

Can someone please explain why this reasoning is incorrect or if I am misunderstanding the passage? Also, is there a good way to better discern the main point of the passage so I don't make this sort of mistake again?

[Adam Tyson]

Answer B can be interpreted as meaning the same thing as "every action performed by an early human... ," so try looking at it this way, bukkaabh. Did the author of passage A assume that everything done by those early humans was driven by evolution or by evolutionary psychology? Or could early humans have done at least some things that were NOT orchestrated by their genes? Stupid things, maybe, or risky things, stuff that did not lead to a greater chance for survival?

If the author of passage A did not assume that everything those early humans did was orchestrated by their genes, then author B couldn't have gotten to a point of saying that assumption was a mistake. That's why answer B is incorrect - author A didn't make that sweeping an assumption, and author B didn't address one that big. He only dealt with the lesser assumption made by author A, that if evolutionary psychology COULD explain a behavior, then it probably DOES explain it.

As to the part about there being many possible explanations for any given behavior, that means the author of passage B is saying you can't ever just point at one explanation for a behavior and say "that explains it, so that must be the explanation." It's not about author A's theory always being wrong, but about it not necessarily being right even if it makes sense in a certain case.

[frk215]

hey folks! I understand why b is wrong and in fact I actually caught that as I was working through the section. But I chose it because with c I felt like reproductive success wasn't necessarily the same thing as the propagation/proliferation of genes. So is the key to choosing c (aside from process of elimination) the fact that these two things are equatable?

PS: Because in order for c to be right, they must be... the phrase reproductive success is used to explain what evolutionary theory is but it isn't repeated later in passage a to explain altruism itself, i think.

[Robert Carroll]

frk215,

Passage A ties those ideas very closely in the first paragraph. In fact, I think it pretty much makes sense to equate them anyway - if something is good for reproduction, by definition is going to be good for proliferation of genes, and vice versa.

Robert Carroll