Researchers designed an experiment to test whether colonies of ants

Question

Researchers designed an experiment to test whether colonies of ants could choose a high-quality nest site from many options more effectively than could individual ants. Colonies and individual ants were both given two levels of tasks: choosing between two nest sites, or choosing from among eight nest sites. In both tasks, half the sites were unsuitable. Researchers discovered that individual ants made much worse decisions when faced with eight options than when faced with two, suggesting that they experienced a cognitive overload. Colonies, on the other hand, chose equally well with either two or eight options, showing that they could better solve the more complex problem as a collective.

According to the experimental results, when the researchers increased the number of site choices, ___X___ were more likely to choose ___Y___than when the researchers presented fewer site choices.

Select for X and for Y the options that jointly complete the sentence in a manner consistent with the information provided. Make only two selections, one in each column.

According to the experimental results, when the researchers increased the number of site choices, ___X___ were more likely to choose ___Y___than when the researchers presented fewer site choices.

Select for X and for Y the options that jointly complete the sentence in a manner consistent with the information provided. Make only two selections, one in each column.

chetan2u · Answer

The catch is MORE for the replacement of X.  
We are told colonies of ants show EQUAL or same capabilities even when the number of sites is increased or decreased. 
But individual ants do display cognitive overload when faced with more options. 
Thus X:  individual ants but not colonies of ants

Y talks of likely outcome when the number of sites are increased.  
We are told in the experiment that individual ants made worse decisions when given more options. 
Thus Y:  an unsuitable nest site

sriharsha4444 · Answer

GMATNinja   ChiranjeevSingh   KarishmaB  
why can't the answer be `colonies of ants, but not individual ants` and `a high-quality nest site` since per the experiment, colonies of ants are doing equally well when the number of options grow but not the case with individual ants. I do agree the original answer also makes sense but not sure how to reject this one

Bismuth83 · Answer

"Colonies, on the other hand, chose   equally well   with either two or eight options"

Your option: "when the researchers increased the number of site choices,  colonies of ants, but not individual ants  were   more likely   to choose a high-quality nest site than when the researchers presented fewer site choices".

As you can see "more likely" in your option is incorrect because in the text it's stated "equally well". In other words, the probability of choosing a high-quality nest by the colony is the same for both experiments (2 & 8) and that is why you can't use "more likely" in your option.

Amity007 · Answer

I found a better explanation for the correct answer.
We have to consider 2 experiments situation,
1- when ants given increased number of sited to choose from
2- when ants given fewer/lesser number of sites to choose from

Now, if we consider “colonies of ants” choosing “higher probability of high quality nest” 
It would be somewhat same or equal chance/probability for both cases. It creates a doubt. When we compare high number of choices to fewer number of choices.

And if we consider “individual ants” and choosing “unsuitable nest” then we can see that we are very sure that if we have given greater number of nest choices to individuals they will end up choosing unsuitable as compared to lesser number of nest.

So I feel comparing 2 situations can be very helpful to come to the conclusion for answers.

egmat · Answer

Hi sriharsha4444,

Great question — this is a really common  trap  on TPA verbal questions, and the distinction is subtle but critical.

Let's plug your proposed combination into the sentence:

"When the researchers increased the number of site choices, colonies of ants, but not individual ants were MORE LIKELY to choose a high-quality nest site than when the researchers presented fewer site choices."

Now look at what the passage actually says about colonies: they "chose equally well with either  two  or  eight  options."

Equally well.  Not better. Not worse. The same.

Your combination claims colonies were MORE LIKELY to pick a good site with  8  options than with  2 . But the experiment showed no improvement — colonies performed the same regardless of the number of choices.   "Equally well" does not equal "more likely."   So your pairing overstates what colonies did.

Now look at the correct pair:

"When the researchers increased the number of site choices, individual ants, but not colonies of ants were more likely to choose an unsuitable nest site than when the researchers presented fewer site choices."

For X = individual ants, but not colonies:  Individual ants made "much worse decisions" with  8  options (cognitive overload). Colonies did equally well. So only individual ants changed behavior — this fits.

For Y = an unsuitable nest site:  Worse decisions means picking bad sites more often. With more options, individual ants were indeed more likely to land on an unsuitable site. This is directly supported.

Key Insight:  The sentence says "more likely," which requires a CHANGE in behavior when options increased.  Individual ants changed (got worse). Colonies did  NOT  change. So only individual ants can fill the X slot, and the direction of their change (worse decisions) matches "an unsuitable nest site" for Y.

Answer: 4A, 2B

Researchers designed an experiment to test whether colonies of ants

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X	Y	Statements
		several nest sites
		an unsuitable nest site
		a high-quality nest site
		individual ants, but not colonies of ants
		colonies of ants, but not individual ants
		both individual ants and colonies of ants

X	Y	Statement
		several nest sites
		an unsuitable nest site
		a high-quality nest site
		individual ants, but not colonies of ants
		colonies of ants, but not individual ants
		both individual ants and colonies of ants

GMAT Two-part Analysis (TPA) Questions

Researchers designed an experiment to test whether colonies of ants

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615 to 715 in 15 Days (Ria's Strategies)

More than Quant/Verbal Abilities: Speed vs. Accuracy

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My Rewards