to the top

#23 - A certain species of bird has two basic varieties

Kdup
LSAT Leader
 
Posts: 31
Joined: Mon Aug 14, 2017 12:15 pm
Points: 31

Hi Powerscore,

I'm trying to understand why " A" isn't correct. I went through doing contenders and losers and I eliminated B &C.... I was then stuck between "A", "D", and "E". .. I realized that it could not be "D" because if a crested bird selects a crested mate then that would show that there is some type of pre disposition that crested bird has towards its own kind, that goes against the conclusion draw that birds preference for crested or non crested mates is learned rather than genetically determined. So, I moved on to answer choice A and E. I selected "A" because it says that birds show presences for mates that have one or another specific physical feature... and I was thinking that these physical features is something that could possibly be liked over time... or a preference.
Matt Griffiths
PowerScore Staff
PowerScore Staff
 
Posts: 8
Joined: Mon Aug 28, 2017 6:30 pm
Points: 8

Good question, Kdup.

In this Strengthen question we are looking for an answer choice that helps the argument, particularly the conclusion that the birds' preference is learned rather than genetically determined.

Answer choice (A) is problematic in a couple of ways. First of all, it mentions only birds of other species. That should be a red flag right off the bat -- how do we know that statements about other species are relevant to this specific type of bird? Second, it does not address whether these birds are raised with other birds possessing this feature. All it tells us is that there is a preference. Is this preference inborn or learned? (A) doesn't give us any insight into that question.

As you noted, (D) actually weakens the argument, as it removes the exposure to crested birds that would give evidence for a learned preference.

(E) is correct because it shows that a relevant, alternate scenario where the birds are raised in a mixed environment leads to a different result. The birds who were raised with crested birds pick crested mates, and the birds who were raised with both crested and noncrested show no preference. That's exactly what we're looking for! Notice that it also specifies birds of that species rather than the birds of a different species mentioned in (A).

Another aspect of this question you may have noted is that it involves a causal conclusion. One way to strengthen a causal conclusion is to show that when the cause does not occur, the effect does not occur. Here, being raised in a crested flock is our cause, and showing a preference for crested mates is our effect. But when the cause does not occur, as in (E) where the birds are raised in a different flock, the effect does not occur either. That helps to strengthen the argument.

Hope this aids you in understanding the question.