Ecologist: Before finding a mate, male starlings decorate their nests with fragments of aromatic plants rich in compounds known to kill parasitic insects. Since these parasites are potentially harmful to nestlings, some researchers have hypothesized that the function of these decorations is nestling protection. However, males cease to incorporate such greenery once egg laying starts, which suggests instead that the function of the decorations is to attract females.

Summarize Argument: Phenomenon-Hypothesis
The ecologist hypothesizes that the reason male starlings use aromatic plants in their nests is to attract females, contrary to previous hypotheses that the plants protected nestlings from parasites. This is based on the observation that these males only incorporate these aromatic plants before egg-laying begins, and stop adding them to nests when egg-laying begins.

Notable Assumptions
The ecologist assumes that there is not an alternate explanation for the male starlings only incorporating the aromatic plants before egg-laying.
The ecologist also assumes that aromatic plants incorporated before egg-laying couldn’t kill parasitic insects over an extended time period, and thus still protect nestlings.

A
Adult starlings are able to defend themselves against parasitic insects.
This is irrelevant, since the effect of parasitic insects on adults is not discussed in the argument. We only care about parasites’ potential harmful effect on nestlings and whether the aromatic plants function to counteract that harm.
B
Male starlings do not decorate their nests in areas with unusually small populations of parasitic insects.
This weakens by providing more evidence that these decorations do have to do with parasitic insects after all, if they are only used in nests in areas where parasitic insects are a threat.
C
Nestlings grow faster in nests that incorporate aromatic plants than in nests that do not.
This seems to weaken by suggesting an alternate explanation for the incorporation of aromatic plants in nests: to help nestlings grow faster. It’s still not clear whether it makes a difference when the decoration occurs, but this certainly doesn’t strengthen.
D
Male starlings tend to decorate their nests with a greater number of aromatic plants when a caged female is positioned adjacent to the nest.
This strengthens by providing direct evidence in support of the ecologist’s hypothesis: males increasing the use of aromatic plants when females are nearby is consistent with those plants functioning to attract females.
E
The compounds in the aromatic plants used by the male starlings to decorate their nests are harmless to nestlings.
This doesn’t affect the ecologist’s hypothesis, since the argument has nothing to do with whether the aromatic plants are harmful to nestlings.

10 comments

Psychologist: In our study, participants who were offered the opportunity to purchase a coffee mug were not willing to pay more than $5. If, however, they were given a very similar mug and asked immediately afterwards how much they would be willing to sell it for, most of them held out for more than $5.

"Surprising" Phenomenon

Why were most study participants unwilling to sell a coffee mug unless they received more than the maximum amount they would have spent to purchase it?

Objective

The right answer will explain a difference between the mugs, the study participants’ states of mind, or the set of circumstances that existed when the participants were in the position of mug buyer vs. mug seller. That difference must result in the participants believing that they either could or should receive more money for the mug than they were willing to spend to purchase it.

A
A person’s assessment of the value of an object depends on his or her evaluation of the inherent properties of the object.

This doesn’t explain why the participants’ assessments of the mug’s value changed when they became the seller—the inherent properties of the object didn’t change, so why would the participants’ value assessments be different?

B
People are usually unable to judge the value of an object when they have possessed it for a long period of time.

This would help if the participants had owned the mug for a long time after they were in the position of buyer and before they were in the position of seller, but the stimulus tells us they were asked about the mug’s price “immediately” after they were given the mug.

C
The amount a person is willing to spend on an object is determined by the amount that object sold for in the past.

This doesn’t help. Even if the participants’ willingnesses to purchase the mug for no more than $5 were based on their knowledge of a previous price, it doesn’t explain why they wouldn’t sell the mug for $5.

D
People tend to value an object that they do not own less than they value a very similar object that they already own.

This describes a key difference between the study participants’ states of mind as mug buyer vs. seller: in the position of seller, they owned the mug, and therefore valued it more highly than before. As a result, they wanted to sell it for more money.

E
People are more likely to undervalue objects they have been given than objects they have purchased.

We want to explain why the participants’ assessments of the mug’s value went up when it was given to them. Instead, this answer indicates that we might expect the opposite. This answer choice also compares given vs. purchased objects, but the stimulus describes desired vs. owned.


5 comments

Bell: Commentators in the media are wrong to criticize the policies Klein implemented. Although her policies are unpopular, they avoided an impending catastrophe. Klein is just the person we need making important decisions in the future.

Soltan: Klein’s policies have been effective, but politics matters. In the future, important decisions will need to be made, and she will not have the political support to make them. So she should step down.

Speaker 1 Summary
Bell argues that Klein is the right person to make important decisions in the future, despite recent media criticism. Why? Because her policy decisions recently avoided an upcoming catastrophe, which is more important than the policies being unpopular.

Speaker 2 Summary
Soltan says that Klein should step down, even though her policies are effective. To support this, Soltan explains that Klein will not have the political support needed to make important decisions in the future.

Objective
We need to find a disagreement. Bell and Soltan disagree about whether Klein should remain in office or step down.

A
Klein’s policies have been effective.
Both Bell and Soltan agree that this is true. Soltan directly states that Klein’s policies have been effective, and Bell indicates agreement by talking about how Klein’s policies averted a future catastrophe.
B
Klein’s policies are unpopular.
Both speakers agree with this. Bell admits outright that this is true, and Soltan implies that Klein’s decisions have been unpopular by discussing how Klein will not have a lot of political support for future decisions.
C
Klein should step down.
Bell disagrees with this and Soltan agrees, meaning this is their point of disagreement. Bell says that Klein is the leader we need in the future, meaning that Klein should stay in office. On the other hand, Soltan directly states that Klein should step down.
D
There are important decisions to be made in the future.
Both speakers agree with this. Bell and Soltan each explicitly discuss the important decisions that will have to be made in the future.
E
Klein’s policies were implemented in the face of an impending catastrophe.
Bell agrees with this and Soltan never disagrees. Soltan doesn’t acknowledge this catastrophe explicitly, but also never says that it wasn’t a problem. So, we can’t say that Soltan disagrees with Bell on this point.

3 comments