Q13 - Psychologist: Idential twins are virtually

[ohthatpatrick]

What does the Question Stem tell us?
Weaken

Break down the Stimulus:
Conclusion: Many of our inclinations are genetic, not environmental.
Evidence: A bunch of identical twins (same genes) who have been brought up in different environments have similar inclinations.

Any prephrase?
If these people have "same genes but different environments", do we have to assume that their similar inclinations are genetic, not environmental? We have to make a case for the anti-conclusion, that "all inclinations are subject to environmental influences." Essentially, we need to think of a way to argue that "even though they grew up in different environments, their similar inclinations are still influenced by environmental factors."

Answer choice analysis:
A) This doesn't feel like a great way to argue that "even though they grew up in different environments, their similar inclinations are environmentally caused."

B) This is super weak, which is always a red flag on Weaken/Strengthen/Explain ("which of the following, if true, …"). There are "a few differences"? Oooh. Scary. More importantly, it still doesn't do the work we need it to do.

C) Not bad. This doesn't help us support our idea that their similar inclinations are environmentally-caused, but it weakens the author's notion that they are genetically-caused. Of course, just because scientists are far from being able to link genes, it still could be true that they ARE in fact linked.

D) This is weird. This is saying that twins who have the same environment end up with different inclinations. Well that definitely sounds like evidence for OUR point of view, that "inclinations are all environmental". If inclinations were genetic and not affected by environment, identical twins should have similar inclinations no matter where they grew up. But this answer says your upbringing DOES matter. When they grow up together, they want to stick out from the other person (an environmental influence), so they develop different inclinations.

E) This strengthens. It sounds like genetic similarity and inclination similarity appear/disappear hand-in-hand.

The correct answer is D.

Takeaway/Pattern: (C) made it sound like "we can't yet prove whether the author is right or wrong". (D) made it sound like "the author looks to be wrong". The author's conclusion involved implicit causation. She assumed, in the case of the identical twins discussed, that their genetic similarity caused their similar inclinations. Our correct answer weakens by attacking that idea. It provides examples when the supposed Cause was Present (these identical twins have genetic similarity), but the supposed Effect was Absent (they do NOT have similar inclinations, in fact they appear to have been environmentally influenced into having different ones).

#officialexplanation

[kitmitzi]

I did not think any of the answer choices really weakened the argument so I picked C because I thought it was the only possible non-strengthening answer.

The correct answer is D: Identical twins who grow up together tend to develop different beliefs, tastes, and careers in order to differentiate themselves from each other.

How does this weaken the psychologist's argument? It's saying the twins have to actively try to differentiate themselves from one another which might imply that they are genetically predisposed to have similar preferences.

[kimyooji]

I had the exact same question as you did, but as I was typing to post this question up, I found the answer! Well,,,at least I think I did. I hope it helps..

so, the conclusion is that many of our inclinations must be genetic not the environmental influences.

ok..so its weaken question...
we're looking for an answer that says "its not genetic!its the environmental influence!!!"

thats what D is saying.
Identical twins who GROW UP TOGETHER tend to develop different beliefs, tastes, and careers in order to differentiate themselves from each other.

meaning: that the twins who grow up together (environmental influence) were so much alike each other, and in order to differentiate themselves from each other they develop different beliefs, tastes, and blah blah blah.

[ManhattanPrepLSAT2]

I really like your answer, kimyooji!

One thing I'd like to add is that the conclusion is a very general one, even though it includes the word "must" --

"Many of our inclinations must be genetic in origin, and not subject to environmental influences."

(C) is just too specific for this context. They do not need to be able to link specific genes to specific inclinations (maybe such links will never be found --maybe they are too complex to understand specifically) --in order to show that some of our inclinations are genetic in origin.

[jason.tarre]

Could (A) have been a correct answer choice if the answer choice had simply said identical twins undergo radical changes in their lifestyle at some point in their lives (and not said many people)? (D) would still be a better answer choice, but ignoring (D) could A, then plausibly be correct? Or does (A) not let us infer whether radical lifestyle changes are genetically or environmentally influenced?

Thanks!

[tibetanguy123]

I also confused with A....

[zainrizvi]

For answer choice (A), who is to say that those radical changes are environmentally influenced? Maybe genetically we are predisposed to undergo specific changes during puberty that alter us quite heavily.

Odd? Yes. Plausible? Yes.

What if identical twins both changed radically from their previous selves, but were similar even after their change?

[ManhattanPrepLSAT1]

Exactly right zainrizvi! The correct answer should cast doubt on whether those inclinations are genetically influenced. Suggesting that there are changing behaviors of people throughout their lives, does not suggest which factor influenced those changes - so as zainrizvi suggested, answer choice (A) still leaves open the possibility that those changes were genetically influenced.

Nice work!

[nthakka]

What is a good reason to eliminate E?

I was thinking that maybe they could still dress the same way and that this is consistent with the argument that this is genetic and not subject to environmental influences?

Another possible reason, that maybe non identical twins could develop similar beliefs, tastes, and careers genetically by virtue of different qualities of their parents. So just because non identical twins have these different qualities it isn't necessarily due to environmental changes. Thus this AC could be consistent with the argument.

Is my reasoning correct?

[sumukh09]

We're talking specifically about identical twins because they're virtually the same genetically, however non identical twins are not virtually the same genetically. The argument concludes that identical twins who grew up in different environments grew up the same and so their inclinations must be genetic in origin rather than environmentally influenced.

E talks about non identical twins but we can't weaken the argument because non identical twins do not have virtually the same genetic makeup as each other like identical twins do.

D on the other hand weakens the claim about nature superseding nurture since they were influenced by the environment they grew up in ie) because they grew up together, they wanted to differentiate themselves from one another

[nflamel69]

Can any geek answer this?

I don't see how D weakens the argument after reading these explanations. The only reason is that I was able to eliminate the rest of them.

the conclusion is that : MANY of our inclinations are genetic, and not due to environmental influences.

premise: identical twins that are away from each other have same blah blah..

The reason why I don't think D weakens is the fact it may weaken that ALL of our inclinations are genetic, but not MANY as stated in the premise. Because it doesn't account for the fact that it is still true that they have different environment but have similar beliefs. To weaken it, don't we have to address another possibility for the similar beliefs in that case? I feel D weakens conclusion, but not the relationship between the premise and conclusion.

[einuoa]

Can any geek answer this?

I don't see how D weakens the argument after reading these explanations. The only reason is that I was able to eliminate the rest of them.

the conclusion is that : MANY of our inclinations are genetic, and not due to environmental influences.

premise: identical twins that are away from each other have same blah blah..

The reason why I don't think D weakens is the fact it may weaken that ALL of our inclinations are genetic, but not MANY as stated in the premise. Because it doesn't account for the fact that it is still true that they have different environment but have similar beliefs. To weaken it, don't we have to address another possibility for the similar beliefs in that case? I feel D weakens conclusion, but not the relationship between the premise and conclusion.

The premise is the study and the conclusion is that our inclinations must be genetic in origin. If D weakens all of our inclinations are genetic, that includes the many inclinations as well. I think there are many ways to weaken this argument, not necessarily addressing other possibilities. The study was showing that
different environmental influences + same genetics = similar inclinations, so in conclusion, everything must be genetic.

D weakens the relationship between the premise and the conclusion because it shows that
same genetics + same environmental influence = different inclinations

If genetics is the only factor in our inclinations, in environment shouldn't be an issue no matter if it's the same or different. D brings up a different reason to address why it's not genetic. The "in order to differentiate themselves form each other" could be thought of as an environmental factor or even a different factor, but it just shows that the inclinations aren't solely due to genetics.

[logicfiend]

AGH I choose D initially, but completely misreading the AC, I changed to E.

D is so the answer!

Ok, like everyone else has already said, we're look for an answer that says NOT genetics, maybe something else (like environmental factors) influences someone's inclinations.

I don't know if anyone has said this explicitly yet, to me D is the answer because it sounds like these twins are CHOOSING their tastes or dislikes intentionally. The fact that they have any control at all over their career/beliefs etc. definitely makes it unlikely it's entirely genetics.

[Zahrav]

Hello,

I chose (B). After reading everyone's responses, i am still having a hard time understanding how (D) is the correct answer.
If the twins are 'different' just for the sake of being 'different,' to me this scenario does not take away from the correlation between genetics > similar inclinations.

The twins described in (D) might have had to try really hard to not give in to the inclination to be similar, and actively try to be different.

But, that doesnt weaken the link described in the argument between genes and inclinations.

How is my reasoning wrong? Please help!

[WesleyC316]

This is an interesting one.

Stimulus
Premise: same gene, different environment, same inclinations.
Conclusion: gene determines inclinations, while environment does nothing.

If that's true, what would happen if it's same gene, same environment? We should have same inclinations as well. But answer choice (D) says otherwise, making it a perfect weakening answer choice.