#14 - A commercial insect trap consists of a small box

[desmail]

Hey team,

I was wondering why answer (C) is wrong here. If the insects are still consuming the pesticide and dying more often in households without traps, maybe its not that they are resistant to pesticide, maybe they avoid the solution when its the trap? So couldn't it be that they are really avoiding the traps and not that they are resistant to the pesticide?

Thanks!

[Steve Stein]

Hey Desmail,

Interesting question. In that cause-effect stimulus, scientists seek to explain why the traps used to be more effective. Their hypothesis: the cause is resistance to pesticide.

Cause Effect

Resistance decreased effectiveness

There are several ways to weaken a causal argument, including the introduction of an alternative cause: answer choice A provides that a glucose aversion could be decreasing the effectiveness of the traps. This would weaken the assertion that the cause was a pesticide resistance.

Answer choice C deals with insects that have eaten the pesticide and then apparently moved to new households. Regardless, if they are not dying, across the board, after eating the pesticide mixture, that would seem to strengthen the claim that they have developed a resistance.

Interesting question and answer choices--please let me know whether this is clear--thanks!

~Steve

[desmail]

But even though in answer (C) it says that they are dying in greater numbers that only means that they are dying more often than the insects in the household with the traps. But the insects in the trap households are still dying.

Also, even if we go with what you said about them still dying across the board,
I'm still thinking "Ok, but why then did they die when they ate the mixture at the trap-free house?" This is almost like a half weaken half strengthen answer, part of it weakens the argument but the other part strengthens it.

Am I just overanalyzing it? Thanks.

[Steve Stein]

Thanks for your response.

The problem with the choice you selected is that it doesn't provide a clear causal connection between the drop in deaths and any other cause. In other words, with all else equal, if they were dying in greater numbers after leaving the houses with the traps, it's not clear what this proves.

This type of cause/effect question is often fairly standard, and as a general rule if you start to feel like you're "forcing" the logic to make an answer work, you might want to reconsider the other answer choices--the correct answer choice in this case was fairly strightforward--since glucose is the other part of the mixture, it's a pretty decent potential culprit.

I hope that's helpful! Let me know--thanks!

~Steve

[Jkjones3789]

Hello I was a little confused with this weaken questions and chose C. Could you please explain the question and why the answer is actually A? Thank You.

[Robert Carroll]

jk,

From the stimulus, we know that this glucose-and-poison trap has changed in its efficacy; ones installed now are not as effective as ones installed previously. The scientists hypothesize that the cause of this change is that pests have developed a resistance to the pesticide. As this is a cause and effect relationship, and the question type is Weaken, anything that provides evidence for an alternative cause would weaken the hypothesis.

Answer choice (C) does not weaken the causal argument of the scientists. It provides evidence that the trap is less effective at killing pests in households that have used it for a while than those that have not, but the scientists' explanation of pesticide resistance is actually consistent with that information, so this doesn't refute the causal argument.

Answer choice (A) provides evidence that indicates it's not that pests are better able to tolerate the poison, but that they are increasingly repelled by the glucose, so the cause of the traps' becoming less effective is not pesticide resistance but the fact that glucose is not attracting pests like it should anymore. This provides an alternative cause for the phenomenon.

Robert Carroll