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# Researchers conditioned a group of flies to associate a particular odo

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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
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B.IF theyy were merely following others, the conclusion stands invalid.
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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
ArtVandaley
B.IF theyy were merely following others, the conclusion stands invalid.

I marked B by POE( by applying negation), bt still did not get the clarity as why B and not A or C is the answer. Request you sincerley if you can help me how to tackle the argument.
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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
How to eliminate B? Can't understand why C is correct here.
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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
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Luckily I got it correct. But I appreciate detailed explanation for selecting B among other options.
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Researchers conditioned a group of flies to associate a particular odo [#permalink]
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gvij2017

The reason why B is the correct answer is pretty straightforward:

" The researchers hypothesized that in the presence of the odor, a fly that retains the conditioned association gives off an alarm signal that arouses the attention of any surrounding flies, retriggering the association in them "

As is evident from the above text that the hypothesis was based on the ability of the flies to detect the alarm signals given by other members of their group.

By assumption negation option B says that the flies were merely following other flies and did not infact detect signals. This option throws the hypothesis out the window if negated , hence is the correct answer
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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
How E could be eliminated ?..Anyone plz explain.

Posted from my mobile device
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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
I got C
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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
breatheanddoit
I got C
Can you explain what led you to choice (C)? The more we know about your thought process, the easier it is for us to help (and the more likely that you'll get a reply!).
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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
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breatheanddoit
I got C
Can you explain what led you to choice (C)? The more we know about your thought process, the easier it is for us to help (and the more likely that you'll get a reply!).

Since in option c - Flies that did not avoid the odour when tested individually were less likely than the other flies to avoid the odour when tested in a group.
So if the flies that didn't avoid the odour individually didn't avoid it in groups too .
It would indicate that the conditional association and not any other reason is responsible for some flies to respond to the odour
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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
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Understanding the sentence:
Researchers basically trained a group of flies to connect with a particular smell with an electric shock. After some hours, researchers tested the flies both individually and in groups. This test was done to determine if the flies still retained the training.
Individual test result: Flies would not avoid the areas with smell
Theory of researchers: When smell is there, a fly that is trained sends a signal to the other flies like a warning and these flies would then avoid the smell.

A. The flies do not give off odors as alarm signals.
--> This answer is irrelevant on the assumption of the researchers

B. Flies that did not avoid the odor when tested individually were not merely following other flies' movements when tested in a group.
This is the right assumption that makes the hypothesis/theory stand. If the flies tested in the group are merely following the movements of the other flies, then the signal thing which researchers assume does not hold.
Therefore, this is the right assumption.

C. Flies that did not avoid the odor when tested individually were less likely than the other flies to avoid the odor when tested in a group.
This does not tell anything as the statement is trying to compare the flies that did not avoid individually vs other flies in the group that would avoid the smell.

D. Prior to their conditioning, the flies would likely have found the odor used in the experiment to be pleasant.
Irrelevant as the kind of smell is not discussed in the passage

E. An electric shock was used during the flies' conditioning and during the later tests.
Also not relevant for the hypothesis as the theory basically deals with the signal sent by induvial flies

Researchers conditioned a group of flies to associate a particular odor with a weak electric shock. Twenty-four and forty-eight hours later the researchers conducted tests on the flies, both individually and in groups, to determine whether the flies retained the conditioning. When tested individually, the flies were significantly less likely to avoid areas marked with the odor. The researchers hypothesized that in the presence of the odor, a fly that retains the conditioned association gives off an alarm signal that arouses the attention of any surrounding flies, retriggering the association in them and thereby causing them to avoid the odor.

The researchers' hypothesis requires which of the following assumptions?

A. The flies do not give off odors as alarm signals.
B. Flies that did not avoid the odor when tested individually were not merely following other flies' movements when tested in a group.
C. Flies that did not avoid the odor when tested individually were less likely than the other flies to avoid the odor when tested in a group.
D. Prior to their conditioning, the flies would likely have found the odor used in the experiment to be pleasant.
E. An electric shock was used during the flies' conditioning and during the later tests.
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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
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gmatt1476
Researchers conditioned a group of flies to associate a particular odor with a weak electric shock. Twenty-four and forty-eight hours later the researchers conducted tests on the flies, both individually and in groups, to determine whether the flies retained the conditioning. When tested individually, the flies were significantly less likely to avoid areas marked with the odor. The researchers hypothesized that in the presence of the odor, a fly that retains the conditioned association gives off an alarm signal that arouses the attention of any surrounding flies, retriggering the association in them and thereby causing them to avoid the odor.

The researchers' hypothesis requires which of the following assumptions?

Passage explanation:
Let us consider there are 6 flies. Now researches trained the flies such that whenever they smell a particular odor (say smell of a nice pie), the flies would associate that smell with a shocking sensation and tend to avoid that area.

Now they conducted two types of tests:
1. Lets say they kept a freshly baked pie in an area. Now out of 6 flies, say 2 flies (A and B) went and sat on pie. They did not recall the shocking sensation on smelling the pie. A and B sat on pie in 7 out of 10 trials and rest sat on pie only in 2 out of 10 trials

2. Now they conducted a similar test with 6 flies. The two flies, A and B, sat on the pie only in 4 out of 10 trials.

Hypothesis: The other flies(other than A and B) sent an alarm signal when they smelled the pie. This alarm signal triggered a shock response in A and B, and hence A and B avoided sitting on the pie

Question type - Assumption
It could be a case, that the other flies did not send a signal. Instead in a group, there generally an alpha fly who the other flies obey. So consider a case, that the shock response was triggered in the alpha fly and it simply moved away from pie. Thus the other flies also followed the fly and moved away from the pie. This suggests that there was no alarm signal.

A. The flies do not give off odors as alarm signals.
The argument does not mention the form of alarm signal. It could be a wink, an odor, a sound anything. So this option does not affect the conclusion

B. Flies that did not avoid the odor when tested individually were not merely following other flies' movements when tested in a group.
Exactly what we thought. It the flies were merely imitating the alpha fly the alarm was never triggered, the shock response was never generated and the hypothesis falls apart Correct answer

C. Flies that did not avoid the odor when tested individually were less likely than the other flies to avoid the odor when tested in a group.
This suggests that the flies A and B, sat on pie less number of times than the other flies in the case when tested in the group than when tested in individually. Okay good. That is supporting the argument but it is not an assumption. The information does not shed any light on why they sat less number of times. Is it because they were merely following the leader or the shock sensation was triggered.

D. Prior to their conditioning, the flies would likely have found the odor used in the experiment to be pleasant.
This is irrelevant. We are trying to find if the odor triggers the sensation. The type of odor does not affect the argument

E. An electric shock was used during the flies' conditioning and during the later tests.
This means that we do not know if the results of the action were because of odor triggering the sensation or because of the physical shocks.

Please correct me if I have misunderstood anything!
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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
I got C because I did not negate the question answer choice properly. Can someone confirm if this is the correct negation for B and C? Thanks in advance. Delete Bold and add in italics

B. Flies that did not avoid the odor when tested individually were not merely following other flies' movements when tested in a group.
C. Flies that did not avoid the odor when tested individually were less more likely than the other flies to avoid the odor when tested in a group.
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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
Conclusion states that The researchers hypothesized that in the presence of the odor, a fly that retains the conditioned association gives off an alarm signal that arouses the attention of any surrounding flies, retriggering the association in them and thereby causing them to avoid the odor.

Now if the flies were merely following the route of the other flies then the conclusion does not hold true.

Other options do not have any effect on the conclusion

Hence B
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Researchers conditioned a group of flies to associate a particular odo [#permalink]
Dear GMATNinjaTwo

I was not able to pick a right one between Choice B&C because I did not understand what they said. Now It seems that I can understand what they wrote:

Choice B: Flies that did not avoid the odor when tested individually were not merely following other flies' movements when tested in a group.
mean:
Flies (let say X) that did not avoid the odor when tested individually were merely following other flies' movements
BUT
Flies X when tested in a group were NOT merely following other flies' movements

Choice C: Flies that did not avoid the odor when tested individually were less likely than the other flies to avoid the odor when tested in a group.
mean:
Flies (let say X) that did not avoid the odor when tested individually were likely the other flies to avoid the odor
BUT
Flies X when tested in a group were LESS likely than the other flies to avoid the odor.

I therefore pick B.
Please correct me if I am wrong in my interpretation from the original statement.
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Researchers conditioned a group of flies to associate a particular odo [#permalink]
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Dear GMATNinjaTwo

I was not able to pick a right one between Choice B&C because I did not understand what they said. Now It seems that I can understand what they wrote:

Choice B: Flies that did not avoid the odor when tested individually were not merely following other flies' movements when tested in a group.
mean:
Flies (let say X) that did not avoid the odor when tested individually were merely following other flies' movements
BUT
Flies X when tested in a group were NOT merely following other flies' movements

Choice C: Flies that did not avoid the odor when tested individually were less likely than the other flies to avoid the odor when tested in a group.
mean:
Flies (let say X) that did not avoid the odor when tested individually were likely the other flies to avoid the odor
BUT
Flies X when tested in a group were LESS likely than the other flies to avoid the odor.

I therefore pick B.
Please correct me if I am wrong in my interpretation from the original statement.

It seems you are trying to make sense but have not understood completely. I guess you might have read these options several times and then trying to figure out what are they saying. Then connect with the right answer to make sense out of it.
In this way, you won't be able to use this learning in next question .
( btw, this is my guess based on some hints: E.g. you said: Flies (let say X) that did not avoid the odor when tested individually were merely following other flies' movements . When individual why would they follow other flies' movements. It makes no sense)

So how to make simple understanding and avoid multiple times reading.

Let's see what C says first:
Quote:
C. Flies that did not avoid the odor when tested individually were less likely than the other flies to avoid the odor when tested in a group.
I know it's a bit confusing in my reading. It wil be more confusing if you try to get everthing in first shot.
Here is : How i tacked its meaning:
Flies that did not avoid the odor -- which flies? ok the flies that actually got the shock
when tested individually --ok so these flies were tested invidually.
were less likely than -comapre with whom? I guess the ones that didn't get shock
the other flies -yup as i guessed, but comparison in what?
to avoid the odor when tested in a group. --> i see, to avoid the shock when these flies were tested in group.
So it means:
2 flies: X. flies that get shock Y. the flies that didn't shock .
X are less likely to avoid shock when tested in group.
I see, so when flies are in group , these flies still get shock.
So when the flies are in group, , retriggering the association in them and thereby causing them to avoid the odor. doesn't work.
It mean it weakens the claim.

Now I can analyze more based on my logic reasoning:
If these flies could avoid shock when in group then it would have strengthen the claim.
( or i can say opposite of C: flies when in group are equally likely to avoid odour when tested in group with the flies that did avoid the odour.
In other words , opposite of B says: X and Y are equally likely to avoid shock when in group. But when X and Y are individually then X is less likely to avoid ( or can say X is more likely to get shock)

I hope you can handle B now.

You try it again what B says.
Quote:
B. Flies that did not avoid the odor when tested individually were not merely following other flies' movements when tested in a group.

FOr your reference here is the meaning:
X when tested individually were not just following movements .
X--> that did not avoid the odor
Think: If they were not just following and still they didn't get shock. So it maybe possible that these flies avoid the odor because other flies might have helped due to retriggering of the association.
So now B make sense and you can see how it fits in the argument.

Key point is: Take the meaning and use logic in your own words. Forget the wording and just see how logic fits in the argument.

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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
The researchers hypothesized that in the presence of the odor, a fly that retains the conditioned association gives off an alarm signal that arouses the attention of any surrounding flies, retriggering the association in them and thereby causing them to avoid the odor.

What is the necessary assumption here? For the hypothesis to remain intact, we need an unstated assumption confirming the alarm signal did indeed arouse the attention of the surrounding flies -- not something else.

A -- This goes against the researchers' hypothesis.

B -- If flies were merely following other flies' movements when tested in a group, then we have reason to doubt the researchers' hypothesis. We definitely need this statement in order for the hypothesis in remain intact.

C -- This is a common trap in assumption questions. This statement is a distinction within the group of flies, but it is not relevant to the researchers' hypothesis.

The scientists hypothesize that in the presence of the odor, a fly that retains the conditioned association gives off an alarm signal that arouses the attention of any surrounding flies, retriggering the association in them and thereby causing them to avoid the odor. Whether flies that did not avoid the odor when tested individually were less likely than the other flies to avoid the odor when tested in a group is not important.

D - Irrelevant -- we're not interested in flies prior to their conditioning.

E - Not a necessary assumption -- we're told the flies were conditioned to associate a particular odor with a weak electric shock. An electric shock does not have to be used during the later tests.
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Re: Researchers conditioned a group of flies to associate a particular odo [#permalink]
Correct Option B

Researchers conditioned (Experiment)
- a group of flies to associate a particular odour with a weak electric shock.
- 24 hrs and 48 hrs hours later the researchers conducted tests on the flies,
- both individually and in groups, to determine whether the flies retained the conditioning.
- When tested individually, the flies were significantly less likely to avoid areas marked with the odour.
The researchers hypothesized that
- in the presence of the odour, a fly that retains the conditioned association gives off an alarm signal
- that arouses the attention of any surrounding flies, retriggering the association in them and
- thereby causing them to avoid the odour.

The researchers' hypothesis requires which of the following assumptions?

A. The flies do not give off odour as alarm signals.
-Flaw: This is one of the facts of the premise of passage, we need is when it does, does it follow or interacts with surronding another flies or not

B. Flies that did not avoid the odour when tested individually were not merely following other flies' movements when tested in a group.
-Correct : Assumption - Comparison between Flies individually and Flies in group – avoid odour and following other flies, the reason for which experiment was conducted

C. Flies that did not avoid the odour when tested individually were less likely than the other flies to avoid the odour when tested in a group.
-Flaw : it’s a simple comparison without any conclusion getting derived from this stem, as in B clearly indicates about the action during the experiment of the flies

D. Prior to their conditioning, the flies would likely have found the odour used in the experiment to be pleasant.
-Flaw: we need assumption during and post result of the experiment, pior is irrelevant

E. An electric shock was used during the flies' conditioning and during the later tests
-Flaw: out of scope
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