PrepTest 104

[lcid:3514] Prep Test 104 LSAT — Reading Comp — S3 Reading comp

Passage

Questions 15-21  .        Homing pigeons can be taken from their lofts and  . transported hundreds of kilometers in covered Remaining source text redacted.
Passage walkthrough
Passage Summary

Topic: Science


Paragraph 1

  • Paragraph note
    • Homing pigeons’ ability to find their way home is probably due to either an ability to keep track of outward displacement or an internal map sense.
  • Views, minor Meta-Structures, and the author's attitude
    • Phenomenon: Homing pigeons can be transported in covered cages hundreds of kilometers to unfamiliar places and, upon release, determine accurate homeward bearings within one minute (first sentence)
    • Experimentation has ruled out the possibility that pigeons read the minds of experimenters (second sentence)
    • Explanations:
      • Pigeons keep track of outward displacement like short-range species such as honeybees (second sentence)
      • They have an internal map sense that allows them to locate themselves on a coordinate system (second sentence)
    • Author’s attitude: “and yet” (first sentence); “remarkable ability” (second sentence); “might keep track” (second sentence); “might have some sense” (second sentence)

Paragraph 2

  • Paragraph note
    • Assessment of explanation 1: It is unlikely that homing pigeons are able to keep track of outward displacement.
  • Views, minor Meta-Structures, and the author's attitude
    • Possible model for keeping track of displacement: internal magnetic compass (second sentence)
      • This has been largely disproved by experiments in which birds were subjected to artificial magnetic fields but were only occasionally affected (third sentence)
    • Another possible model for keeping track of displacement: track direction and degree of acceleration and deceleration of turns, and timing of individual legs of journey (fourth sentence)
      • This has been largely disproved by experiments in which birds were transported in dark, with constant rotations, or under anesthesia (fourth-fifth sentences)
      • No one has combined the countermeasures in all of these experiments into one experiment (sixth sentence); so this possibility has not totally been ruled out
    • Author’s attitude: “seems unlikely” (first sentence); “might involve” (second sentence); “only occasionally affected” (third sentence); “ought to impair or eliminate” (fourth sentence); “have no effect” (fifth sentence); “unfortunately, no one has performed the crucial experiment” (sixth sentence)

Paragraph 3

  • Paragraph note
    • Assessment of explanation 2: possibility that pigeons have an internal map sense seems more plausible, but it has not been proven.
  • Views, minor Meta-Structures, and the author's attitude
    • Unclear what form this internal “map sense” takes (first sentence)
    • Papi’s theory: internal map is olfactory; pigeons come to associate wind-blown smells from different directions with different areas (second sentence)
      • Experimentation at first seems to support this, because pigeons whose nostrils are plugged find their way home slowly (fourth sentence)
    • Author’s attitude: “seems more promising” (first sentence); “remains mysterious” (first sentence); “Papi has posited” (second sentence); “have only to sniff the air” (third sentence); “Papi conducted” (fourth sentence)

Paragraph 4

  • Paragraph note
    • Papi’s olfactory explanation has been weakened by experimentation.
  • Views, minor Meta-Structures, and the author's attitude
    • Schmidt-Koenig and Phillips’s experiment: pigeons didn’t distinguish natural, signal-laden air from filtered air (first sentence)
    • Papi’s results could be explained in other ways (second sentence):
      • It was the trauma of the nostril-plugging that caused pigeons’ slow navigation, not the fact that they couldn’t smell (third sentence)
      • Another experiment: when nasal tubes are used to allow for comfortable breathing but no smelling, pigeons behave normally (fourth sentence); and when anesthetic is used to block smell sense but not breathing, pigeons behave normally (fifth sentence)
    • Author’s attitude: “one problem” (first sentence); “failed to detect” (first sentence); “admit of simpler, nonolfactory explanations” (second sentence); “it seems likely” (third sentence); “distracting and traumatic” (third sentence); “no disorientation is evident” (fourth sentence)

Main Point: Two explanations have been proposed for the remarkable ability of homing pigeons to find their way home: the first, which posits that the birds keep track of external displacement, seems to be less likely than the second, which posits that the birds are able to locate themselves on an internal coordinate system that has not yet been characterized.

Key Lines?

Paragraph 1, Sentence 1 (P1 S1) - Statement of phenomenon

P1 S2 - Two explanations

P2 S1 - First explanation unlikely

P3 S1 - Second explanation more likely, but still mysterious

Meta-Structure?

Phenomenon/Explanation: This passage uses a Phenomenon/Explanation Meta-Structure. The phenomenon to be explained is stated in the first sentence: the amazing ability of homing pigeons to be transported hundreds of kilometers in covered cages to unfamiliar places and set a course for home within a minute of being released. Two possible explanations are proposed, namely, the possibility that the birds keep track of their route from home on the outward journey, and that the birds have an internal coordinate system that they use to navigate. The author argues that the second has more support than the first, but concedes that the nature of the internal map system has yet to be determined, though it has been shown by experimentation that it is unlikely to be olfactory.

The minor Meta-Structure is List. The author lists two possible explanations for the phenomenon and then, for each explanation, lists the experiments that have been performed in order to test it.

The author’s viewpoint is not difficult to discern throughout the passage. They favor the second explanation over the first, and are interested in finding out the nature of the pigeons’ internal map sense. In fact, they spend the second half of the passage recounting the experiments that have been done to try to figure this out.

Last Thoughts?

This passage is straightforward in terms of what it’s discussing and what the author’s perspective is, but, as with many science passages that discuss experimentation, the author does not declare a definitive explanation of the phenomenon; the reader is left with probabilities. However, the evidence is well organized.

Question prompt

Which one of the Remaining source text redacted.
Why the credited answer is right

Credited answer: D

The notes below walk through why it fits the stem and how to eliminate the rest.

Question Type

Science

Strategy Overview

Review Papi’s theory regarding the pigeon’s homing ability, determine weaknesses in that claim to anticipate how to weaken it, and select the answer choice that makes the claim less convincing.

Answer Anticipation

We'll approach Weaken questions in Reading Comprehension in a very similar manner as we would in Logical Reasoning. We can review the excerpt from the passage, just like we'd carefully read an argument in LR. We’ll then interrogate the claim for any weaknesses, as the correct answer on both RC and LR will probably weaken the claim by exploiting a problem. Additionally, causation flaws are commonplace on Weaken questions in both RC and LR, so we should be especially mindful of those.This is a causal claim. Papi’s theory is that, if pigeons’ olfactory sense is blocked, they aren’t able to find their way back home. The most common way to weaken a causal claim on the LSAT is by undermining the correlation. In this case, the correct answer might show other instances in which the pigeons’ sense of smell is blocked, but they find their way home anyway. This technique is often called "cause without the effect." Alternatively, the correct answer could show an effect produced without the supposed cause preceding it. In this case, that might involve the pigeons’ not being able to find their way back home even if their sense of smell is not interfered with. This technique is often called "effect without the cause." Either would undermine the correlation linking the pigeons’ sense of smell to their ability to home .: That said, many things could feasibly weaken Papi’s claim that the pigeons’ internal map system is based on their sense of smell ,: so we should keep an open mind as we progress through the answer choices. We'll start by asking ourselves, "Does this make Papi’s theory that pigeons home using their sense of smell less convincing?"

Answer choices

  1. A
    Even pigeons that have Remaining source text redacted.
    Why choice A is not credited

    (A) Does this answer choice make Papi’s theory that pigeons home using their sense of smell less convincing?

    No. This answer choice doesn’t even mention the pigeons’ sense of smell, the central feature of Papi’s theory. The fact that the pigeons in question were raised in several different areas doesn’t imply any effect on their sense of smell. So this is not the right answer choice because it does not address Papi’s central theme.

  2. B
    Pigeons whose sense of Remaining source text redacted.
    Why choice B is not credited

    (B) Does this answer choice make Papi’s theory that pigeons home using their sense of smell less convincing?

    No. This answer choice, if true, would actually support Papi’s theory that the pigeons’ ability to home is based on their sense of smell. This answer choice echoes P3 S4, which describes Papi’s experiments showing that pigeons whose nostrils had been blocked find their way home more slowly than those whose nostrils hadn’t been blocked.

    Because it would strengthen Papi’s case rather than weaken it, this is not the right answer choice.

  3. C
    Even pigeons that have Remaining source text redacted.
    Why choice C is not credited

    (C) Does this answer choice make Papi’s theory that pigeons home using their sense of smell less convincing?

    No. Similarly to (A), this answer choice does not explicitly address the pigeons’ sense of smell, and the fact that the pigeons here were raised in the same loft yet take different routes home doesn’t imply anything about their sense of smell. This answer choice is thus not the right one because it doesn’t address the pigeons’ olfactory sense.

  4. D
    Even pigeons that have Remaining source text redacted.
    Why choice D matches the stem

    (D) Does this answer choice make Papi’s theory that pigeons home using their sense of smell less convincing?

    Yes. Papi’s theory is that pigeons can detect from which way the wind is blowing when they’re at home and thus associate different smells with different areas of their surroundings (P3 S2). Birds who, as in this answer choice, are transported beyond the range of any of the smells with which they are familiar yet can still find their way back home have demonstrated that they didn’t use an olfactory map to home, since they couldn’t possibly have constructed one. This answer choice is an example of the cause without the effect, and definitely weakens Papi’s argument.

  5. E
    Pigeons' sense of smell Remaining source text redacted.
    Why choice E is not credited

    (E) Does this answer choice make Papi’s theory that pigeons home using their sense of smell less convincing?

    No. This answer choice is irrelevant to Papi’s argument. Papi is not arguing that the pigeons’ sense of smell is better or more acute than that of other birds; Papi is arguing that pigeons use their sense of smell in a special way, to construct an olfactory map of their surroundings (P3 S2). The fact that other birds might smell things better or worse than pigeons is irrelevant to the way in which the pigeons’ use their sense of smell, according to Papi.

    Thus, this answer choice does not strengthen or weaken Papi’s argument.

What this tests

Discussion

  • Answer D 1 reply

    Started by RitaW

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