#25 - The interstitial nucleus, a subregion of the brain's

[Adam Tyson]

Answer C is wrong for at least two reasons that I can see, lsatquestions. First, the conclusion in the argument is about male cats, whereas answer C is only about female cats. It makes little difference what's happening with the females when all we want to know is about the possible causal link for males.

Second, even if we take the female cats as providing evidence about male cats, this evidence appears to support the hypothesis rather than undermine it. In C, the correlation between disease X and an abnormally large interstitial nucleus holds for females as well as males, and that could be seen as support (though not proof) that the size of this thing does have some impact on susceptibility to the disease. In essence, answer C is showing a parallel case where the alleged cause and effect are both present, and that's a classic strengthener!

Could it be the other way around, with the disease causing the enlargement? Sure. Would an answer that pointed out that possibility weaken this argument? Absolutely. But answer C doesn't suggest that is what happening. All it tells us is that the correlation found in males is also found in females, and that doesn't hurt the argument.

[pineapplelover18]

hiya!

wanted to see if my understanding of D was correct, and just to ensure I understand I want to play around with what could have made D correct.

So the conclusion is the size of the nuclei causes us to know if the cat can contract disease x.

the Premise for this is that normally male cats have smaller average nuclei than that of females; and the Premise has this phenomenon it tries to explain (neurobiologist experiment): that of males (with nuclei the size of average females) who had died from disease X. So based on this correlation, author goes into a kind of causal mode starting their conclusion. As always to debunk cause we can say a. Alt cause for disease X (not avg size), b. Cause (male nuclei size of female nuclei) but NO effect and vice versa (No effect, but Cause), c. 3rd thing that accounts for both cause and effect, or d. just no relation (the neurobiologist was drunk and mixed a bunch of stuff up or something).


AC D tries to do (pretty much) CAUSE -- NO effect to weaken, by stating that of 1000 who did NOT have disease X, 5 had a larger than Average nuclei. The problem is this doesn't follow from the stim bc D says larger than AVG MALE, and we know the cause would have to be LARGER THAN AVG FEMALE. If D were right, it would have had to say of the 1000 in a controlled experiment, there was male cats with larger than avg FEMALE nuclei (cause present), BUT they did not contract disease X (effect absent), breaking the casual link (cause -- no effect).

Is this correct?

on the other hand E is right bc it debunks the casual chain all tg (going for the no relation route). It shows that the Hypothalamus (where the nuclei is) had been found to have no casual link to Disease Y which is the catch all of disease X. If there's no relation with the big groups, there must be no relation with the smaller players!

In general, I find that weaken/strenthen questions really differ in the complexity of the premise and conclusion and convoluted language, but the core ideas all stay the same!

Anywho, would love some feedback on my approach

[pineapplelover18]

hiya!

wanted to see if my understanding of D was correct, and just to ensure I understand I want to play around with what could have made D correct.

So the conclusion is the size of the nuclei causes us to know if the cat can contract disease x.

the Premise for this is that normally male cats have smaller average nuclei than that of females; and the Premise has this phenomenon it tries to explain (neurobiologist experiment): that of males (with nuclei the size of average females) who had died from disease X. So based on this correlation, author goes into a kind of causal mode starting their conclusion. As always to debunk cause we can say a. Alt cause for disease X (not avg size), b. Cause (male nuclei size of female nuclei) but NO effect and vice versa (No effect, but Cause), c. 3rd thing that accounts for both cause and effect, or d. just no relation (the neurobiologist was drunk and mixed a bunch of stuff up or something).


AC D tries to do (pretty much) CAUSE -- NO effect to weaken, by stating that of 1000 who did NOT have disease X, 5 had a larger than Average nuclei. The problem is this doesn't follow from the stim bc D says larger than AVG MALE, and we know the cause would have to be as LARGE AS FEMALE NUCELI. If D were right, it would have had to say of the 1000 in a controlled experiment, there was MOST of the male cats whom had nuclei as large as FEMALE nuclei (cause present), BUT they did not contract disease X (effect absent), breaking the casual link (cause -- no effect).

Is this correct?

on the other hand E is right bc it debunks the casual chain all tg (going for the no relation route). It shows that the Hypothalamus (where the nuclei is) had been found to have no casual link to Disease Y which is the catch all of disease X. If there's no relation with the big groups, there must be no relation with the smaller players!

In general, I find that weaken/strenthen questions really differ in the complexity of the premise and conclusion and convoluted language, but the core ideas all stay the same!

Anywho, would love some feedback on my approach

[Dana D]

Hey Pinapplelover,

I think you are right on here with your analysis for both, good job!

[jk3530]

Hello,

I have a question about the stimulus itself. The author states, "The size of the interstitial nucleus determines whether or not male cats can contract disease X."

I didn't really interpret this as a causal claim (that the size causes disease X) because of the phrasing "determines" and "can."

For example, you can say: "Having both X and Y chromosomes, compared to only XX chromosomes, determines whether a person can contract disease Z." This doesn't mean chromosome Y is causing disease Z, only that its presence determines the possibility of contraction.

If I interpreted the author as simply saying the size causes the disease, it would've been much more straightforward....

[Jeff Wren]

Hi jk,

The causal reasoning here is trickier than simply "the size of the interstitial nucleus causes disease X." Instead, the causality expressed is that "the size of the interstitial nucleus causes susceptibility to disease X." (The word "can" in the conclusion, which you noted, gets at this idea of susceptibility.) It may be helpful to think of susceptibility to disease X as its own condition/effect, similar to how a person's immune system being damaged/weakened can make that person more susceptible to diseases.

The word "determined," which you also noted, is a causal indicator, and "determined by" appears on our list of causal indicator words in "The Logical Reasoning Bible."