PrepTest 142, Section 2, Question 18
To find out how barn owls learn how(101 more words not shown)
The scientists' reasoning is vulnerable(7 more words not shown)
- AIt fails to(16 more words not shown)
- BIt assumes that(10 more words not shown)
- CIt attributes human(6 more words not shown)
- DIt neglects to(13 more words not shown)
- EIt uses as(9 more words not shown)
Reading the argument
Taking off the lenses doesn't necessarily undo what they did to the owls' developing vision.
While the young owls wore the lenses, they acted as though sounds came from farther to the right than they really did. After the lenses came off, the error remained. The scientists interpret that persistence as evidence that the mature owls no longer use vision to locate sounds.
But what if the owls still use their vision and their vision is now impaired? An effect caused during development could remain after the object causing it is removed. We would then see continued mistakes without needing to conclude that sight no longer plays a role.
What we’re looking for
For the flaw question, that is the alternative to keep in mind: removing the lenses is different from establishing that the owls' vision has returned to normal.
Working the answers
- ACorrect
Permanent visual impairment could explain why removing the lenses didn't fix the sound-location errors. The owls might still rely on sight, but the information supplied by their sight could remain distorted. The experiment therefore doesn't isolate the scientists' explanation from this alternative. We don't need to prove damage occurred to see that they haven't ruled it out.
- B
The argument doesn't need every owl to have equally good sight. Owls could differ in visual ability while scientists investigated how early visual experience affects later sound localization. The specific missing question is whether the experimental lenses caused a lasting impairment, not whether all owls have identical eyesight.
- C
Nothing here says owls reason through problems the way humans do. The scientists infer something about the senses used to locate sounds from the owls' behavior. That inference may be too quick, but it doesn't attribute distinctly human thought processes to the birds.
- D
Eagles or pigeons could respond differently without settling what happened to these barn owls. The conclusion concerns barn owls, so the scientists need to distinguish explanations for the owls' results. Investigating every other bird species isn't required to do that.
- E
The results are relevant: the scientists altered vision and observed errors in locating sounds. Relevant evidence can still fall short of establishing a particular explanation. A study of something unrelated, such as a cow's liver, would have a different problem. Here the problem is that the pertinent experiment leaves another explanation open.
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